Light Pollution: Responses and Remedies

For further volumes:http://www.springer.com/series/3192

Patrick Moore’s Practical Astronomy Series

Light Pollution

Responses and Remedies

Second Edition

Bob Mizon

Bob MizonWimborne, UK

ISSN 1431-9756ISBN 978-1-4614-3821-2 ISBN 978-1-4614-3822-9 (eBook)DOI 10.1007/978-1-4614-3822-9Springer New York Heidelberg Dordrecht London

Library of Congress Control Number: 2012939110

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v

Preface

In July 2003, the 11 members of the UK Parliament’s Science and Technology Select Committee convened beneath the high ceiling of a gilded meeting room at the House of Commons in London. They were there to gather evidence for an enquiry into light pollution and the gradual disappearance, since the 1950s, of the night sky over much of the country. Politicians, engineers, astronomers (including the Astronomer Royal, Sir Martin Rees) and many other interested individuals gave evidence.

A now prominent politician, at that time a junior education minister, concluded during his evidence that “if we cannot give young people access to the night sky because of where they live, we have to fi nd other ways of giving them practical engagement with the subject” – by, he said, buying Internet time on telescopes abroad! The committee, in their report, expressed surprise “that the Minister… did not see the irony of his own words. Schools are now obliged to buy time to enable their pupils to view stars in the southern hemisphere, when the UK’s own night skies should be there for all to view for free.”

We require our children to appreciate “the wider universe” in the school curricu-lum, but the vast majority of them see very little of their universe because of the pall of wasted light that hangs over every city – and many villages and rural spaces – in our increasingly urbanized world.

Thousands of stars should be visible to the unaided human eye from a dark place, but it is becoming increasingly dif fi cult to fi nd such places. There are sites in mod-ern town centers where nothing outside the Solar System is ever seen in the sky.

vi Preface

Wherever you are in the developed world, whether it’s in your back garden or a well-equipped professional observatory, it is increasingly likely that the night sky will be tainted, degraded by wasted light. The second half of the twentieth century saw the gradual disappearance of the starry sky over large tracts of our planet.

Together with radio interference, space debris and aircraft contrails, light pollu-tion contributes to the increasing barrier between the human race and its cradle, the cosmos. We are all made of star-stuff, nearly every atom in our bodies having been created in some distant and probably long-dead star, some explosive event whose reverberations have long since dissipated. Whatever is left of our material selves, when our planet fi nally sears in what Bertrand Russell called “the vast death of the Solar System,” will be redistributed and recycled into the cosmic depths that we can no longer, in the twenty- fi rst century, properly see and appreciate.

Robert Macfarlane told of both the value and the loss of the heavens in his book The Wild Places 1 :

On a cloudless night, looking upwards, you experience a sudden fl ipped vertigo, the sensa-tion that your feet might latch off from the earth and that you might plummet upwards into space. Star-gazing gives us access to orders of events, and scales of time and space, which are beyond our capacity to imagine: it is unsurprising that dreams of humility and rever-ence have been directed towards the moon and the stars for as long as human culture has recorded itself.

Our disenchantment of the night through arti fi cial lighting may appear, if it is noticed at all, as a regrettable but eventually trivial side-effect of contemporary life. That winter hour, though, up on the summit ridge with the stars falling plainly far above, it seemed to me that our estrangement from the dark was a great and serious loss.

Light Pollution: Responses and Remedies is not a ‘science book’ in the usual sense. It is in the Practical Astronomy series because it concerns itself with the night sky and because it offers a selection of objects that may be studied in moderately light-polluted skies; but it is hoped that its contents may point to courses of action that astronomers and friends of the environment, be they ardent campaigners (Fig. 1 ) or mildly concerned individuals, can follow in order to contribute to the alleviation and eventual solution of the skyglow problem, and of the many other problems caused by wasted light.

This book deals with human perceptions as much as with the discipline of astronomy; with our aspirations and needs as well as with our technical achieve-ments. It explores one of the saddest paradoxes of modern life: the fact that our developing technology can provide us with stunning images of the near and far universe, and at the same time blind our eyes to the stars above.

Wimborne, UK Bob Mizon

1 Robert Macfarlane: The Wild Places, Granta Publications, 2007 (ISBN 978-1-86207-941-0).

viiPreface

Fig. 1 Dark-sky campaigners from around the world meet at Genk, Belgium, 2005 (Photo: Friedel Pas)

ix

Acknowledgements

This second edition owes much to the encouragement and help of members of the British Astronomical Association’s Campaign for Dark Skies (Dr. Chris Baddiley, John Ball, Graham Bryant, Dr. John Mason, Martin Morgan-Taylor, Mike Tabb), UK lighting professionals (especially Tom Webster), members of the International Dark-Sky Association (IDA), Eric Jones (SSE Museum of Electricity, Christchurch), Dr. Steven Lockley (Harvard Medical School), Richard Murrin, David Nash, Dr. Woody Sullivan (University of Washington, Seattle), Nik Szymanek, Steve Tonkin and fellow members of the Wessex Astronomical Society. My special thanks to Pam Mizon for her patience and support.

Photographs

All photographs in this book are by the author unless otherwise credited. Permissions have been acquired for other photos and for quotations from other works.

xi

Contents

Part I The Gift of Light?

1 Living with Light ....................................................................................... 3The Limits of Human Vision ...................................................................... 3Heaven’s Lights ........................................................................................... 8The Range of Natural Radiation ................................................................. 13Sunlight ....................................................................................................... 16Moonlight .................................................................................................... 22Starlight ....................................................................................................... 24The Zodiacal Light ...................................................................................... 29The Gegenschein ......................................................................................... 30

2 Light Pollution: The Problem Defined .................................................... 33Lights and More Lights: The Rise of Artificial Illumination ...................... 33Skyglow ...................................................................................................... 40Turning the Tide .......................................................................................... 48

3 Adverse Impacts of Inefficient Artificial Lighting ................................. 53Waste of Energy and Money ....................................................................... 53Domestic Floodlights .................................................................................. 58Road Lights ................................................................................................. 59Degradation of the Environment ................................................................. 62

xii Contents

4 Artificial Lighting, Quality of Life and Health ...................................... 77Lighting and Human Health ........................................................................ 77

5 Artificial Lighting and Crime .................................................................. 85Crime Reduction ......................................................................................... 87‘Security’ Floodlighting: Anti-Lights? ....................................................... 93Conclusions ................................................................................................. 97

6 Quantifying the Problem .......................................................................... 99Measurement ............................................................................................... 99The Bortle Scale .......................................................................................... 103New Lamps for Old..................................................................................... 108Types of Lamps ........................................................................................... 109Shielding and Directional Adaptation in Luminaires ................................. 118

Part II Piercing the Veil: Techniques and Targets

7 Techniques ................................................................................................. 123Filters .......................................................................................................... 124CCD Astronomy ......................................................................................... 127

8 Targets ........................................................................................................ 131Andromeda (October) ................................................................................. 135Aquarius (August–September) .................................................................... 137Aquila (July) ............................................................................................... 140Aries (October–November) ......................................................................... 141Auriga (December) ..................................................................................... 142Boötes (April–May) .................................................................................... 143Camelopardus (December) ......................................................................... 144Cancer (January–February) ......................................................................... 146Canes Venatici (April) ................................................................................. 147Canis Major (December–January) .............................................................. 148Canis Minor (January–February) ................................................................ 150Capricornus (August) .................................................................................. 151Cassiopeia (October) ................................................................................... 151Cepheus (August–September) .................................................................... 153Cetus (October–November) ........................................................................ 156Coma Berenices (March–April) .................................................................. 156Corona Borealis (May) ............................................................................... 156Cygnus (July–August) ................................................................................ 157Delphinus (July–August) ............................................................................ 159Draco (March–June) ................................................................................... 160Gemini (December–January) ...................................................................... 162Hercules (May–June) .................................................................................. 163Lacerta (September) .................................................................................... 163Leo (February–March) ................................................................................ 165

xiiiContents

Leo Minor (February–March) ..................................................................... 166Lynx (January–February) ............................................................................ 166Lyra (June–July) .......................................................................................... 168Ophiuchus (May–June) ............................................................................... 169Orion (December–January) ......................................................................... 170Pegasus (September–October) .................................................................... 171Perseus (November–December) ................................................................. 172Pisces (September–October) ....................................................................... 174Sagitta (July–August) .................................................................................. 174Scutum (June–July) ..................................................................................... 176Serpens (May–June) .................................................................................... 176Taurus (November–December) ................................................................... 177Triangulum (October–November) .............................................................. 179Ursa Major (February–March) .................................................................... 180Ursa Minor (May–June) .............................................................................. 183Virgo (March–May) .................................................................................... 183Vulpecula (July–August)............................................................................. 184

Part III Dark Future?

9 Light Pollution Solutions for the Twenty-First Century ....................... 189What Should Manufacturers Be Doing About Light Pollution? ................. 192What Should Legislators Be Doing About Light Pollution? ...................... 199What Should Local Authorities Be Doing About Light Pollution?....... ..... 202What Should Architects Be Doing About Light Pollution? ........................ 206What Should Retailers Be Doing About Light Pollution? .......................... 208What Should Astronomers Be Doing About Light Pollution? ................... 209Courses of Action ....................................................................................... 209

Appendix 1 The StarLight Conference 2007: Declaration in Defence of the Night Sky and the Right to Starlight (La Palma Declaration) .................................... 215

Appendix 2 Organizations Committed to Reducing Light Pollution ....................................................................... 221

Appendix 3 Starry Starry Night ............................................................... 223

Appendix 4 The Future of Street Lighting – A Professional’s View ........................................................................................ 227

Appendix 5 Recommendations for Good Light Control ........................ 231

Appendix 6 Extracts from Articles on the Legal Aspect of Light Pollution (Reproduced With Permission) ............. 239

Appendix 7 Some Lighting Myths (Reproduced by kind permission of Dr. David Crawford, IDA) ............................ 243

xiv Contents

Appendix 8 Advice from IDA and CfDS .................................................. 249

Appendix 9 Examples of Governmental Guidelines on Good Lighting Practice .................................................... 253

Appendix 10 The IDA’s “Simple Guidelines for Lighting Regulations for Small Communities, Urban Neighborhoods, and Subdivisions” ...................................... 255

Appendix 11 Extracts from the Revised Tucson and Pima County Outdoor Lighting Control Ordinances .................. 259

Glossary ........................................................................................................... 265

Bibliography .................................................................................................... 269

About the Author ............................................................................................ 275

Object Index .................................................................................................... 277

Subject Index ................................................................................................... 279

xv

List of Figures

Fig. 1.1 A clear night sky. Orion looks down upon the unlit village of Ansty, in Dorset................................................ 4

Fig. 1.2 A Milky-Way type spiral galaxy: NGC 7331, in Pegasus (Photo: Alan Jefferis) ..................................................................... 5

Fig. 1.3 Two-million-year old light from M31 (Photo: Alan Jefferis) ......... 5Fig. 1.4 A 30 s exposure: Jupiter and Saturn in Taurus, 2000 Aug 11 ........ 7Fig. 1.5 The atmosphere (Diagram courtesy of Nigel Marshall) ................. 8Fig. 1.6 Clouds: the astronomer’s bête noire ............................................... 10Fig. 1.7 Drifting contrails draw a veil across a clear sky ............................. 11Fig. 1.8 A veil of contrails over Northern Europe (Courtesy Deutsche

Forschungsanstalt für Luft und Raumfahrt) ................................... 12Fig. 1.9 Sky-wonder: a god (Jupiter) and a brighter goddess

(Venus) meet (1988 February 29) .................................................... 13Fig. 1.10 The electromagnetic spectrum (Diagram courtesy

of Nigel Marshall) .......................................................................... 14Fig. 1.11 Earthshine ....................................................................................... 15Fig. 1.12 Dust clouds are prominent in this photograph

of the Milky Way. The brightest object is Jupiter ........................... 16Fig. 1.13 Our stable star – the Sun (Photo: Sheri Lynn Karl) ........................ 17Fig. 1.14 The solar spectrum on a kitchen wall ............................................. 18Fig. 1.15 The aurora of 2000 April 6–7, from my back garden..................... 19Fig. 1.16 Mercury sets below the Pleiades, 1996 April 24 ............................ 20Fig. 1.17 The evening star: Venus at twilight ................................................ 20Fig. 1.18 Mars (below centre) nears its red rival Antares in Scorpius ........... 21Fig. 1.19 Jupiter and Bob’s 21-cm/8.5-in. reflector ....................................... 21

xvi List of Figures

Fig. 1.20 Moonlight: a midnight Moon and a 20-s exposure create a daylight scene .................................................................... 22

Fig. 1.21 The Moon at first quarter, 2010 December 13. The line between lunar day and night is known as the terminator (Photo: Len Telford) ....................................................................... 23

Fig. 1.22 The Milky Way flows through Cassiopeia and Cygnus in a dark, rural night sky ................................................................. 24

Fig. 1.23 Deneb is the brightest star in this 3-min exposure from Child Okeford, Dorset ........................................................... 25

Fig. 1.24 The Pointers of the Plough indicate the Pole Star, high above the marquee of a school’s summer camp ..................... 25

Fig. 1.25 Supernova 1993J in M81 (NGC 3031) ........................................... 27Fig. 1.26 Nova Aquilae 1999 December 4. The ‘new’ star is near

Delta Aquilae, and is arrowed on the accompanying chart. Altair is the brightest star at the top of the photo ........................... 28

Fig. 1.27 An ancient constellation: Orion, the Osiris of the Pharaonic Egyptians (Photo: Chris Bowden) .................................................. 29

Fig. 1.28 The zodiacal light from La Palma (Photo: Alan Drummond) ........ 30Fig. 1.29 Veil across the heavens – light pollution blots out the

southern stars .................................................................................. 31

Fig. 2.1 Stone and shell oil lamps (Courtesy SSE Museum of Electricity, Christchurch) .................................................................................. 34

Fig. 2.2 A bulky carbon arc streetlamp from the 1880s next to the surprisingly small original filament lamp by Swan (Courtesy Eric Jones, SSE Museum of Electricity) ....................... 34

Fig. 2.3 Bob with a replica of Swan’s first filament lamp (Courtesy SSE Museum of Electricity) .......................................... 36

Fig. 2.4 Poorly directed emissions: much of the light misses the church .... 37Fig. 2.5 Shielded light in a supermarket car park, preventing

light spill into houses ...................................................................... 38Fig. 2.6 Glare dominates the environment in this photo taken

on the outskirts of London (Photo: Edward Hanna) ....................... 39Fig. 2.7 Most of the light from this car park floodlight will go into

the sky (Photo: Mike Tabb) .............................................................. 39Fig. 2.8 The massed and mostly poorly directed lights of Canford

Heath, Dorset .................................................................................. 40Fig. 2.9 Skyglow over Poole: the “hot spot” is caused

by the floodlights of the cross-channel ferry terminal .................... 41Fig. 2.10 The city of Bath by night, 1950s and 2000

(Photo: Mike Tabb) ......................................................................... 42Fig. 2.11 Some of the large numbers of new, downward-directed

road lights replacing old wasteful types in the UK ........................ 43Fig. 2.12 Urbanisation of the countryside near John O’Groats

(Photo: Bill Eaves) ......................................................................... 44

xviiList of Figures

Fig. 2.13 Europe by night (Copyright 1996 W.T. Sullivan and Hansen Planetarium) ................................................................................... 44

Fig. 2.14 A farm light shines into a neighbouring garden (Photo: Graham Bate) ..................................................................... 45

Fig. 2.15 Warrington, Cheshire: a car lot’s “security” floodlight intrudes into premises well outside its perimeter (Photo: Ian Phelps) ......................................................................... 45

Fig. 2.16 Looking towards Stonehenge from the east, 2011: a golf range steals the ancient stars (Photo: CfDS) .................................. 46

Fig. 2.17 The lights of the world by night, from space (Copyright 1994 W.T. Sullivan and Hansen Planetarium) ............. 47

Fig. 2.18 Tim Hunter (left) and David Crawford, founders of the IDA (Courtesy IDA) ............................................................. 49

Fig. 2.19 The committee of the Campaign for Dark Skies, 2011: left to right, Chris Baddiley, Mike Tabb, Bob Mizon, David Paul, Martin Male, Tom Webster, Graham Bryant (Absent: Darren Baskill, Stuart Hawkins, Martin Morgan-Taylor) ................................................................... 49

Fig. 2.20 The diffusion of power station and factory steam plumes is striking in this Landsat image of the north-west Midlands of England, taken from an altitude of about 900 km/560 miles (Copyright Focal Point A-V, Portsmouth) ...................................... 50

Fig. 3.1 Wasted light from UK streetlights: Portsmouth (Photo: Ron Arbour) ....................................................................... 54

Fig. 3.2 City lights left on in the small hours of the morning (Photo: Darren Baskill) .................................................................. 55

Fig. 3.3 Wasteful design in a street light: high-pressure sodium lights illuminate the chimneys above them (Photo: Chris Baddiley) .................................................................. 56

Fig. 3.4 A poorly mounted “Rottweiler” light which illuminates premises across the street ............................................................... 58

Fig. 3.5 (a) FCO road luminaire with careful optics, designed for residential streets (Courtesy D.W. Windsor Ltd). (b) FCO in profile; this type is increasingly seen on Britain’s main roads (Courtesy Urbis Lighting Ltd). (c) FCO with multiple lamps; often used on roundabouts and busy road junctions (Courtesy Siemens Ltd) .................................................................. 60

Fig. 3.6 Bob Mizon and David Paul present the Campaign for Dark Skies’ Award of Appreciation to Ginny Clarke, Chief Highways Engineer of the UK Highways Agency ............... 61

Fig. 3.7 Glaring sports floodlights at a leisure centre. The centre received a CfDS Good Lighting Award when the lights were re-angled (Photo: Gerard Gilligan) ................................................. 62

Fig. 3.8 Poorly angled floodlights dazzle drivers on this urban road .......... 63

xviii List of Figures

Fig. 3.9 A well enclosed flat-glass light at a holiday park in France ........... 64Fig. 3.10 Light intrusion: light spill from a car park in a rural

area illuminates a room in a nearby house (Photo: Richard Murrin) ................................................................. 65

Fig. 3.11 An intrusive streetlight shines through the windows of houses (Photo: CfDS) ................................................................. 66

Fig. 3.12 A species in decline: the house sparrow, whose young are insectivorous (Photo: Steve Smith) ........................................... 68

Fig. 3.13 A glow-worm signals its position at dusk beneath a fine display of noctilucent clouds (Photo: Dave Tyler) ............... 71

Fig. 3.14 Birds’ circadian rhythms are seriously disturbed by night-time floodlighting of their habitats (Photo: Chris Baddiley) .................. 72

Fig. 3.15 A floodlit tree (Photo: Andreas Haenel) ......................................... 73

Fig. 4.1 Intrusive light cut down by FCO lights in a residential area (Photo: Urbis) ......................................................................... 78

Fig. 4.2 Light intrusion into a first-floor bedroom ....................................... 81Fig. 4.3 Night in the city: darkness is a thing of the past. Gloucester

at night (Photo: Chris Baddiley) ..................................................... 81Fig. 4.4 Los Angeles, night-time view (Photo: CfDS) ................................ 83

Fig. 5.1 Rioters in an English city, summer 2011 (Photo: Alex Cater)......................................................................... 86

Fig. 5.2 Glare from a rural car park light that would conceal any wrong-doing occurring there (Photo: Richard Murrin) ........... 86

Fig. 5.3 More lights that prevent the observer from seeing (it’s an airport) (Photo: IDA) .......................................................... 87

Fig. 5.4 A “security” light in a secluded area may act as a “courtesy light” for criminals ......................................................................... 90

Fig. 5.5 “Security” lights shining into the eyes of approaching drivers (Photo: CfDS) ..................................................................... 91

Fig. 5.6 Site of a ram-raid, carried out by the light of a street lamp ............ 92Fig. 5.7 Glare: a poorly aimed light in rural Northern Scotland

(Photo: Bill Eaves) ......................................................................... 94Fig. 5.8 An outside lamp with its sensor mounted beneath,

making it impossible to angle it down further ................................ 94Fig. 5.9 Low-power shielded exterior lighting illuminates a porch

and garden adequately, without glare or spill into neighbouring premises (Photo: IDA) ............................................. 96

Fig. 6.1 A Sky Quality Meter ...................................................................... 100Fig. 6.2 The night sky at Prayway Head, Exmoor, SW England

(Photo: David Brabban) .................................................................. 100Fig. 6.3 This view of Malvern and Worcester taken from nearby

hills shows plainly that most of the waste light comes from the luminaires, not from the ground (Photo: Chris Baddiley) .............. 102

xixList of Figures

Fig. 6.4 Reflection from a thin veil of low cloud over Edinburgh (Photo: Chris Baddiley) .................................................................. 102

Fig. 6.5 Ideal atmospheric conditions: a crystal-clear winter sky over central Dorset ................................................................... 103

Fig. 6.6 The night sky over Sark, the Channel Islands’ dark-sky preserve. Only a few distant house lights (exaggerated on this exposure) intrude into a pristine sky (Photo: Martin Morgan-Taylor) .............................................................................. 105

Fig. 6.7 Suburban night sky: Orion in a light-polluted winter sky .............. 106Fig. 6.8 Light over a big city (Photo: Chris Baddiley) ................................ 107Fig. 6.9 A decorative LED light on the Clifton Suspension Bridge

in Bristol: shielded and not too bright for the task (Photo: Pam Mizon) ....................................................................... 109

Fig. 6.10 Old LPS road lights of the kind which are (at long last) fast disappearing in the UK (Photo: Chris Baddiley) ............................ 110

Fig. 6.11 New metal halide road light in a seaside town: note the “mast”-style column ................................................................. 112

Fig. 6.12 A triply environmentally friendly LED light: well-directed, solar powered, and it goes off when there is nobody around! (Photo courtesy of Zeta Solar) ........................................................ 113

Fig. 6.13 The statue of William and Caroline Herschel in their garden, close to the spot from which Uranus was discovered (Photo: Mike Tabb) ......................................................................... 114

Fig. 6.14 Globe lights now illuminate the area behind the Herschels’ garden ..................................................................... 115

Fig. 6.15 A globe light painted black on one side in an attempt to retrieve darkness for an upper-storey bedroom .......................... 116

Fig. 6.16 Newport, Shropshire: the stars I learned in boyhood are veiled by a supermarket’s car park globe lights (since capped) ................ 116

Fig. 6.17 A woman stands near a globe light and is easily seen (Courtesy IDA) ............................................................................... 117

Fig. 6.18 The woman seen in Fig. 6.17 has moved into the less illuminated space beneath the globe light (Courtesy IDA) ..... 117

Fig. 6.19 The fact that most of the light from this car park globe goes up instead of down is excellently illustrated by this IDA photo ........................................................................... 118

Fig. 6.20 Stacked louvres confine the light from this bollard lamp to the ground (Courtesy DW Windsor Lighting) ............................ 120

Fig. 7.1 Some LPR filters (Courtesy Ninian Boyle, Venturescope) ............ 124Fig. 7.2 My small run-off-roof observatory in Colehill,

with its 21-cm/8.5-in. reflector ....................................................... 127Fig. 7.3 Urban CCD image of M27, the Dumb-bell Nebula

(Photo: Nik Szymanek and Ian King) ............................................ 128Fig. 7.4 Urban CCD image of M13, the great globular cluster in Hercules

(Photo: Nik Szymanek and Ian King) ............................................ 128

xx List of Figures

Fig. 8.1 What a third of a million people throw into the sky: light pollution over Poole and Bournemouth ................................. 132

Fig. 8.2 Bob’s venerable Charles Frank 21-cm (8.5-in.) reflector ............... 133Fig. 8.3 The old 1980s lamps in my street threw a high

percentage of their emissions skywards ............................................ 134Fig. 8.4 The day the new FCO lamp arrived opposite my observatory ....... 134Fig. 8.5 New metal halide lamp in my street – goes off at midnight ........... 135Fig. 8.6 The shields installed by the local council to protect

my observing site are visible on this luminaire .............................. 136Fig. 8.7 Better lighting, more stars: looking north from my

back garden above two FCO streetlights ........................................ 137Fig. 8.8 Gamma Andromedae is the bright star here beneath

Comet C/1995 O1 (Hale-Bopp) on 1997 Mar 31. The comet’s tail sweeps towards the ‘W’ of Cassiopeia ..................................... 138

Fig. 8.9 NGC 752. ........................................................................................ 139Fig. 8.10 t1 Aqr to S2970 .............................................................................. 140Fig. 8.11 Finding R Aql ................................................................................. 141Fig. 8.12 NGC 1907. ...................................................................................... 142Fig. 8.13 Field of 14 Aur ............................................................................... 143Fig. 8.14 ‘Kemble’s Cascade’ (‘The Wristwatch’) to the left

of Comet C/1996 ............................................................................ 144Fig. 8.15 Chain of pairs in Camelopardus and Cassiopeia ............................ 145Fig. 8.16 M67 ................................................................................................ 147Fig. 8.17 Finder chart for Y Canum Venaticorum ......................................... 148Fig. 8.18 A ‘star-hop’ to h3945 ..................................................................... 149Fig. 8.19 Stars near S1149 ............................................................................. 150Fig. 8.20 Field of WZ Cas ............................................................................. 152Fig. 8.21 NGC 457 ......................................................................................... 153Fig. 8.22 S2813, S2816, S2819 ..................................................................... 154Fig. 8.23 A ‘star-hop’ to RW Cep .................................................................. 155Fig. 8.24 Finder chart for T CBr .................................................................... 157Fig. 8.25 Motion of 61 Cyg: positions in 1970 and 1992. ............................. 158Fig. 8.26 Star chains near SAO 50246. .......................................................... 159Fig. 8.27 Motion of S2398 against background stars: positions

in 1967 and 1989. ........................................................................... 161Fig. 8.28 A miniature Cassiopeia in Draco. ................................................... 162Fig. 8.29 NGC 7209.......................................................................................... 164Fig. 8.30 NGC 2903. ...................................................................................... 165Fig. 8.31 NGC 2683. ...................................................................................... 167Fig. 8.32 From Vega to T Lyr ........................................................................ 168Fig. 8.33 IC 4665, the ‘HI!’ cluster ................................................................ 169Fig. 8.34 NGC 6633 and Comet 1987S (Bradfield) ...................................... 170Fig. 8.35 NGC 7331 ....................................................................................... 172Fig. 8.36 St 4 .................................................................................................. 173Fig. 8.37 Finder chart for U Sge .................................................................... 174

xxiList of Figures

Fig. 8.38 38 Finder chart for WZ Sge ............................................................ 175Fig. 8.39 Finder chart for R Ser ..................................................................... 177Fig. 8.40 From Aldebaran to NGC 1647 and HU Tau ................................... 178Fig. 8.41 M33 ................................................................................................ 179Fig. 8.42 From 23 UMa to NGC 2880 ........................................................... 181Fig. 8.43 NGC 3992 ....................................................................................... 183Fig. 8.44 NGC 6940 ......................................................................................... 185

Fig. 9.1 A hill NOT too steep to climb: Bath University’s sports lighting, seen in this photo taken in 2000 by Mike Tabb, has now been replaced with FCOs and the skyglow has been minimised. The scheme won the BAA’s Good Lighting Award ............................................................................... 190

Fig. 9.2 Bob presents the Campaign for Dark Skies’ Award of Appreciation to broadcaster John Humphrys, who has often involved himself in the dark skies debate (Photo: CfDS) ..... 191

Fig. 9.3 A well-directed outdoor light on a school in Luton, England ........ 192Fig. 9.4 “Sky-friendlier” exterior light, illuminating

only the area to be lit ...................................................................... 193Fig. 9.5 An advertisement at a lighting exhibition, using stars

as a feature ...................................................................................... 194Fig. 9.6 “Sky-friendlier” FCO lights (black casings) replace old LPS

types at a rural roundabout .................................................................. 195Fig. 9.7 (a) Glare and skyglow from a rural roundabout lit

by old LPS lamps; (b) the same scene after refitting with cut-off lamps: sideways glare and skyglow are much reduced (Photo: John Ball) ............................................................. 196

Fig. 9.8 Glare from an indifferently mounted ‘security’ light, 200 m away, which forced members of the Wessex Astronomical Society to abandon one of their traditional observing sites in the New Forest ............................................................................ 197

Fig. 9.9 Bulkhead light ................................................................................ 198Fig. 9.10 One government department which has set the trend

with well-directed lights: the UK Highways Agency’s Martin Hazle (left) receives the British Astronomical Association’s Good Lighting Award from CfDS committee member Stuart Hawkins (Photo: CfDS) ....................................................... 200

Fig. 9.11 Galloway Forest Park ..................................................................... 200Fig. 9.12 Night sky over Exmoor, south-west England: a National Park

with a good lighting strategy. Location: Winsford Hill (Photo: David Brabban) .................................................................. 201

Fig. 9.13 Stonehenge silhouetted against spill light from the nearby town of Amesbury (Photo: Grant Privett) ........................... 203

Fig. 9.14 East Dorset District Council have light pollution on their agenda: leader Don Wallace receives the Good Lighting award (Photo: EDDC) .................................................................... 203

xxii List of Figures

Fig. 9.15 Some church floodlighting is far too random, and allows a large fraction of emissions into the sky (Photo: Chris Baddiley) .................................................................. 206

Fig. 9.16 A city nightscape, with buildings clamouring for attention .................................................................................... 207

Fig. 9.17 Preparing for a garden star party .................................................... 211Fig. 9.18 I wish you clear skies ..................................................................... 213

The Gift of Light?

Part I

3B. Mizon, Light Pollution: Responses and Remedies, Patrick Moore’s Practical Astronomy Series, DOI 10.1007/978-1-4614-3822-9_1, © Springer Science+Business Media New York 2012

Living with Light

Chapter 1

The day-night cycle of our rotating planet orchestrates the behaviors of nearly every living thing. For countless millions of years, it has determined the ebb and fl ow of life on Earth. Our distant ancestors acknowledged the importance of the Sun, Moon and stars in their lives by deifying them. Indeed, the 7 days of the week re fl ect the fact that there are seven bright objects in the sky (Sun, Moon and fi ve naked-eye planets) that move against the starry background according to regular cycles and rhythms. The human species has recently succeeded in bringing its own light to the world: we long ago learned to harness and domesticate fi re, and much more recently fi lled our homes and streets with arti fi cial lighting. Is our new-found power to bring light to our darkness causing us to lose touch with some of the natu-ral lights that have guided, comforted and inspired us throughout our history?

The Limits of Human Vision

The Dutch optician Hans Lippershey is usually credited with the invention of the telescope, at the beginning of the seventeenth century. It may well be that others were working on similar devices at the time, and that Lippershey was merely the fi rst to patent; English astronomers are quick to point out that mathematician and surveyor Leonard Digges was reportedly experimenting with ‘Proportional Glasses’ as early as the 1550s. In 1590, again in Holland, Zacharias Janssen created what might be called the fi rst practical microscope.

Before these inventions began to reveal the wonders of the macrocosm and the microcosm to us, we were dependent on our eyes alone, and the universe must have seemed a much simpler place. To the early hominids of the Great Rift Valley,

4 1 Living with Light

the Milky Way might have been literally a river of cloud or a distant swarm of innumerable insects bisecting the sky. The Sun and the Moon became generous deities, warming the day and giving light for night-time foraging. The moving lights of the planets contrasted mysteriously with the reassuringly fi xed patterns of the stars.

Observing the starry sky on a clear, moonless night, from a location well away from population centers (Fig. 1.1 ), can be both mystical and unsettling. The enor-mous dome of the heavens may engender feelings of insubstantiality and remote-ness, and the thousands of stars visible to the unaided eye crowd out half-remembered constellation patterns.

With one exception (the Andromeda Galaxy), everything we see without optical aid in the sky belongs to our medium-sized spiral galaxy, the Milky Way, a system like countless others (Fig. 1.2 ). It may hold as many as 200 billion (2 × 10 11 ) stars, in a matrix of clouds of gas and dust from which future solar systems will arise. For every human being on Earth, there may revolve around the galactic center some 33 stars. The Andromeda spiral (M31) is the nearest major galaxy to our own, at a distance of 2.2 million light years (Fig. 1.3 ). Within it swarm at least 250 billion (2.5 × 10 10 ) stars. The light from this dim, oval glow travels towards us at

Fig. 1.1 A clear night sky. Orion looks down upon the unlit village of Ansty, in Dorset

5The Limits of Human Vision

300,000 km/186,000 miles per second through a foreground of Milky Way stars. M31 is the furthest thing that we can perceive directly with any of our senses. To say that a dark sky lets us see further is most certainly an understatement.

From a dark rural retreat, our eyes see, out of all these teeming drifts, between 2,000 and 3,000 stars only. There are people with exceptional vision who see perhaps 7,000.

Fig. 1.2 A Milky-Way type spiral galaxy: NGC 7331, in Pegasus (Photo: Alan Jefferis)

Fig. 1.3 Two-million-year old light from M31 (Photo: Alan Jefferis)


The human eye, like all mammalian eyes, is a complex organ. The light-sensitive cells used for vision (rods and cones) at the back of the retina; the optic nerve, transporting impulses from the retina to the brain; and the various structures (lens and muscles) involved in focusing incoming light onto the retina – all combine to convert photons into electrical impulses the brain can further convert into a sharp image. Also, there are photosensitive ganglion cells at the front of the eye detecting light for circadian and other non-visual responses.

Like a camera, the eye focuses light from the environment onto a sensitive sur-face. This controls the amount of incoming light and creates a pattern perceived as an image of that environment.

The retina is an extension of the forebrain. Its light-sensitive rods and cones, fairly similar in structure though the rods are more cylindrical, are embedded in the ‘photoreceptor layer’ of the retina. In the human eye, rods outnumber cones by about 21. Each eye has about six million cones, closely packed into the centrally located fovea, where most light is focused. Cones contain three visual pigments, differentiate colors, and work mainly in daylight. The 120 million rods, with only one photosensitive pigment, have weaker visual acuity and are found more loosely distributed right across the retina.

Rods are collectively more sensitive than cones, and largely take over visual function in the dark. At night things appear to lose color, as rods dominate. We can just about see colors in bright stars, but optical aid is usually necessary really to appreciate this. The clustering of cones and absence of rods in the fovea explains why averted vision works – why faint objects in a telescope fi eld may suddenly appear if we look slightly to one side of them. Paradoxically, we see objects more clearly at night by not looking straight at them, allowing more rods to function. The light-sensitive pigment in rods, rhodopsin, is a complex molecule. It is formed by a reversible chemical reaction in low-light conditions, and the resultant process of dark adaptation can take up to 30 min in total darkness. The use of a red light at night is recommended for observers, because rhodopsin will react minimally to its particular wavelengths and adapted night vision will not be affected. Photographs taken with relatively short exposures (short in astrophotography terms) of just a few seconds (Fig. 1.4 ) reveal many times more stars than we can ever appreciate with the visual equipment that we have evolved.

There is another type of ocular photoreception, however. In a series of studies through the 1990s, Russell Foster and colleagues showed that the physiology of mice with various degrees of loss of rods and cones could still respond to the light-dark cycle, even when rods and cones were completely absent. These animals could maintain synchronization of their circadian (24-h) pacemaker with the light-dark cycle even with no measurable visual response to light. These studies showed that neither rods nor cones were necessary for maintaining circadian and other ‘non-visual’ responses to light.

It has been established that there is a third class of photoreceptor in the mam-malian eye, different in placement, structure and function from rods and cones. A subset (<0.5%) of retinal ganglion cells, equivalent to relay cells between the visual photoreceptors and the brain, is directly photosensitive and contains a novel

7The Limits of Human Vision

photopigment called melanopsin, which is most sensitive to short-wavelength blue visible light. Melanopsin was discovered in 1998 by Ignacio Provencio (University of Virginia) and colleagues when studying specialized light-sensitive cells in the skin of frogs. Only these ganglion cells are light-sensitive and they project directly to the areas of the brain that mediate non-visual responses to light, such as the site of the circadian pacemaker in the hypothalamus and the brain area mediating pupil-lary responses to light.

The ability to detect light-dark cycles, which in turn indicates time of day and time of year, is vital to living successfully on Earth, where most organisms have to contend with the challenge presented by the 24-h light-dark cycle. Species need to fi nd their temporal niche and have evolved the circadian clock to measure day length and anticipate 24-h environmental time cues. Even eyeless single-celled organisms, it has been discovered, will detect and react to the changes caused by the succession of day and night.

Dr. Steven Lockley, of Harvard Medical School, is a leading expert on the responses of human physiology to light and darkness. He discusses this novel pho-toreceptor system in the Campaign for Dark Skies’ Blinded by the Light (2009), Chap. 4, beginning: ‘ Much as the ear has dual functions for audition and balance,

Fig. 1.4 A 30 s exposure: Jupiter and Saturn in Taurus, 2000 Aug 11


the human eye has a dual role in detecting light for a range of behavioral and physi-ological responses separate and apart from sight, including suppression of pineal melatonin production, stimulation of morning cortisol production, pupillary con-striction, heart rate and temperature regulation, enhancement of alertness and per-formance, changes in brain activity patterns, phase-shifts of the circadian pacemaker and even stimulation of circadian clock gene expression.’

So the celestial rhythms above us are echoed by our biological rhythms, and those of all our fellow creatures, responding to ancient stimuli that are suddenly being compromised by arti fi cial lighting.

Heaven’s Lights

Our limited human vision is only one of the natural factors that combine to rob us, even in the darkest places, of the vast majority of heaven’s night-time lights. Our next big problem if we want to see stars is that we have to observe the rest of the universe through a multi-layered and busy sea of gases, Earth’s atmosphere (Fig. 1.5 ). It has a total mass of the order of 5 × 10 15 metric tons, about one-millionth of the mass of Earth as a whole.

Fig. 1.5 The atmosphere (Diagram courtesy of Nigel Marshall)

9Heaven’s Lights

The lowest level of the atmosphere, the troposphere, is deepest at the equator (around 28 km/17 miles) and at its most shallow at the poles (around 7 km/4.5 miles). In this layer most of the world’s weather occurs, and life processes are maintained. Temperature decreases in the troposphere with increasing altitude, and great air masses slowly turn and interact as temperature differentials and the plan-et’s rotation and relief steer them. What we normally understand by our ‘atmo-sphere,’ with its active appearance and constantly changing weather, is merely the lowest few kilometers of a much vaster entity.

Above the troposphere extends the thermally more stable but much more tenu-ous stratosphere, devoid of clouds, with a ceiling at about 60 km/37 miles. High- fl ying modern jet aircraft pass through the base of the stratosphere, and manned balloons have penetrated it, but only rockets have ever climbed into its highest reaches. Next come the mesosphere (or lower ionosphere), whose ceiling is at approximately 90 km/56 miles, and the thermosphere (or upper ionosphere), extending far upwards to about 1,000 km/625 miles. Incoming cosmic dust parti-cles, swept up by Earth in its 90,000 kmph/66,000 mph progress around the Sun, burn brightly in the mesosphere as they encounter layers dense enough to abrade them, and meteors are the visible result. The upper stratosphere and lower meso-sphere contain the ozone layer, which plays a vital part in shielding us from the Sun’s lethal ultra-violet radiation.

The ionosphere also contributes to our well-being, by soaking up X-rays. Here, rare fi ed gases are ionized as they absorb solar radiation, enabling high-frequency radio transmissions to be sent around the world, as signals are re fl ected back down-wards from the ionized layer. Radio waves of similar wavelengths from space are scattered away from the planet by the ionosphere. The beautiful polar aurorae, described in more detail later, also inhabit this region. Further upwards still, the exosphere, an assemblage of loose particles rather than a layer, and most famously containing the Van Allen radiation belts, gradually fades into the near-vacuum of outer space.

Con fi ned as we are to the bed of this turbulent ocean of air, it is perhaps surpris-ing that we see as much as we do of what lies outside Earth’s atmosphere. Its cease-less motions cause the stars to apparently twinkle (scintillation), as their light traverses the last disrupting millisecond of its enormously long journey to our eyes. Astronomers use the term ‘seeing’ to describe the relative steadiness and transpar-ency of the atmosphere, as judged by the appearance and behavior of a telescopic image. The old but reliable Antoniadi scale is still in use by many observers when recording their observations, its criteria being:

1. Perfect seeing, without a quiver; 2. Slight undulations, with appreciable intervals of calm; 3. Moderate, with large tremors; 4. Poor, with constant undulation; 5. Very bad seeing, scarcely allowing the making of a rough sketch.


Ever-present droplets and minute particles (aerosols), suspended in countless num-bers in the atmosphere, interfere by absorption and scattering with much of the light passing through, causing extinction and distortion of objects near the horizon. There are many different kinds of aerosols. These include mineral particles lifted from deserts, volcanic ash, salt crystals evaporated from sea spray, pollen grains, bacteria, spores, and minute waste products of our industrial society. Aerosols play an important role as condensation nuclei for atmospheric water droplets.

Water suspended in the atmosphere (Fig. 1.6 ) is the chief culprit in attenuating or completely hiding the light from distant bodies, and not only on cloudy nights. Many modern optical astronomers endure the discomfort of high-altitude spells in remote mountaintop observatories, situated above the worst of the turbulence and cloud, beneath clearer air through which the night sky is more effectively observed. A modern manifestation involving water in suspension is beginning to occupy the minds of astronomers, especially in Europe and North America, as they see thin condensation veils, left by merging aircraft contrails, spreading slowly across the skies during even the clearest of days (Figs. 1.7 and 1.8 ). The increase in air traf fi c generally means that this will possibly be the next problem that the astronomical community will have to take on board in its constant battle for a clear view.

Those of us living in brightly lit towns, and seeking the best possible experience of the star-strewn heavens without having to climb a mountain, may yet escape to

Fig. 1.6 Clouds: the astronomer’s bête noire

11Heaven’s Lights

our own preferred dark place, in order to see fainter night-sky objects such as the Andromeda spiral. Even the darkest skies, however, are not as black as we might imagine. We can never really see a totally light-free backdrop to the scattered stars, since the night sky has a natural ‘glow.’ This faint luminescence is caused by sun-light re fl ected from myriads of dust particles distributed throughout the Solar System, and by impacts of energetic particles from the depths of the universe, and also from the Sun, upon the uppermost layers of Earth’s atmosphere. A tiny contri-bution comes also from large numbers of Milky Way stars, and even from remote galaxies, which are individually beyond naked-eye visibility but combine to add to the general dimly luminous effect.

In spite of all the natural factors seemingly conspiring to draw a veil across the stars, our poor view of the heavens has played a continuous and enormously important part in human affairs. The fact that Homo sapiens is equipped with the musculature to look upwards while maintaining balance for sustained periods may have been the key to the door leading to our faculty of wonder, and to our contem-plation of a ‘scheme of things’ greater than our immediate surroundings. The explorer, the mystic, the poet and the scientist residing to differing degrees in all of us may largely owe their existence to the starry vault that early hominids tried somehow to understand and relate to, during the nights of millions of years ago (Fig. 1.9 ).

Fig. 1.7 Drifting contrails draw a veil across a clear sky


Much of the mythology of modern cultures and religions re fl ects this sky-won-der, and any primary school teacher will tell you that there are two things in the early science curriculum that light up the eyes of modern 5-year-olds: dinosaurs and outer space, both of them remote, magical, vast, tempting with the twin lures of the totally unattainable and the visually splendid.

During the second half of the twentieth century, public interest in the cosmos grew as modern space missions, from Sputnik through Voyager and Apollo to Galileo and Cassini , vastly increased our knowledge of planetscapes and pro-cesses within the Solar System. Ever more sophisticated radio dishes, earthbound

Fig. 1.8 A veil of contrails over Northern Europe (Courtesy Deutsche Forschungsanstalt für Luft und Raumfahrt)

13The Range of Natural Radiation

detectors and orbiting telescopes continue to reveal undreamed-of facets of the deeper universe. However, the opportunity to experience the night sky directly remains important. The assumption that Earth is all that exists, and that stars and planets belong in picture books, on fi lm and TV screens and computer monitors, because they cannot be seen in skies invaded by wasted upward light, is an ulti-mate and dangerous vanity.

The Range of Natural Radiation

The complete electromagnetic spectrum of radiation (Fig. 1.10 ) rains down inces-santly upon our planet: the whole range of cosmic wavelengths, from those of the very longest radio waves (10 5 m) to the piercing beams of the most energetic X-rays (10 −11 m) and gamma rays (10 −14 m), fl oods into the topmost layers of the atmo-sphere. Also, high-velocity particles, or cosmic rays, penetrate the atmosphere to various depths, and countless trillions of ghostly neutrinos pass unhindered right through the planet, and everything on it, every day.

The fact that our atmosphere is transparent only to certain radio and visible-light radiations, the so-called radio and light ‘windows,’ means that, although we are

Fig. 1.9 Sky-wonder: a god (Jupiter) and a brighter goddess (Venus) meet (1988 February 29)


protected from the worst that high-energy radiation might do to our bodies, we have to send spacecraft up above the atmosphere in order properly to study the universe at those wavelengths denied to us by our shield of air.

Today’s high-technology orbiting observatories and terrestrial radio telescopes will doubtless be superseded in the far future by remotely controlled instruments working through the frigid, 2-week-long nights on the far side of the Moon. Although set on the Moon’s dusty surface, these detectors will be literally in outer space, with an unspoiled view of the cosmos. If they are located at the center of the lunar far side, they will be shielded by nearly 3,500 km/2,200 miles of rock from Earth’s radio ‘noise,’ and from earthlight or earthshine, the lunar equivalent of moonlight upon Earth (Fig. 1.11 ). The Earthward side of the Moon is bathed at night in sunlight re fl ected from the bluish planet, four times wider in the Moon’s sky than the Moon in ours. Earth is never seen from about 41% of the Moon’s surface.

Throughout scienti fi c history, and especially as telescopes have increased in power since the early seventeenth century, students of the night sky have announced the existence of ever greater numbers of luminous objects, showing a wide range of forms and activity. Galileo Galilei, observing through a fairly primitive refractor in 1610, realized and reported that ‘the Milky Way is nothing but a mass of innu-merable stars planted in clusters,’ and today’s monster telescopes continue to fi sh up ever more distant and fainter galaxies. Increasingly, since Galileo turned his spyglass to the Milky Way, it has occurred to many people that, if Earth’s atmo-sphere is transparent to the wavelengths of visible light, and if there are so many stars and galaxies in whatever direction we look, then the entire dome of heaven ought to be covered with luminous points, and the night sky should be bright instead of dark.

Fig. 1.10 The electromagnetic spectrum (Diagram courtesy of Nigel Marshall)

15The Range of Natural Radiation

So why is the sky dark at night? This conundrum is known to science as Olbers’ paradox, after Heinrich Olbers (1758–1840), a German physician and amateur astronomer who was the fi rst to discuss the problem in depth, in the 1820s. Astronomers remember Olbers nowadays more for his treatment of this perplexing question than for his equally meritorious work on comets and their orbits, and his discovery, from his own observatory in Bremen, of the asteroids Pallas and Vesta, the second and fourth minor planets to be detected.

Olbers’ paradox is explained chie fl y by the expansion of the universe. The unchanging, uniform cosmos of bygone centuries is no more, and we realize that the attenuation and reddening of the energy of very distant starlight, caused by the enormous velocities of recession of the fl eeing galaxies, explain why we are not dazzled by those distant stars as well as by the Sun. So the darkness of the night sky seems chie fl y due to what E. R. Harrison of the University of Massachusetts eloquently called ‘the infrared gloom of the Big Bang.’ With clouds of silicon and carbon dust (Fig. 1.12 ) within our own galaxy also contrib-uting to the absorption and dimming of starlight, we now have to accept that it is not just our turbulent atmosphere and the wasted energy from the lights of mod-ern civilization that deny us a deep view of the stars, but the history and nature of the universe itself.

Fig. 1.11 Earthshine


Sunlight

Our G-type, sub-dwarf star (meaning, confusingly, that it is classi fi ed as a little bigger, not smaller, than a dwarf star) drives all our weather, grows our food and, through fossil fuel energy, powers our vehicles, lights our homes, and runs our machines. For all the Sun’s apparent violence, it is a reassuringly stable star (Fig. 1.13 ). Life on this planet would be impossible if there were a variation of just a few percent in its energy output, the product of the conversion into helium of some 564 million tons of hydrogen every second, of which 4 million tons are anni-hilated and radiated as energy.

Fig. 1.12 Dust clouds are prominent in this photograph of the Milky Way. The brightest object is Jupiter

17Sunlight

Our ration of this energy is but a tiny fraction of the whole, the mean daily value of the solar radiation striking the top of Earth’s atmosphere being 342 W/m 2 . A simple way to appreciate the nature of solar light is to place a prism on a Sun-facing windowsill, and watch the stack of vivid colors projected onto the opposite wall move slowly across the room as the hours pass – evidence of the rotation of Earth seen from your armchair (Fig. 1.14 ).

The Sun lights the night sky indirectly in the form of the northern lights, or aurora borealis (in the southern hemisphere, the aurora australis ). High-speed elec-trons ejected in clouds from the Sun, especially around solar maximum, are funneled along Earth’s magnetic fi eld lines towards the poles. They interact with atoms and molecules of oxygen and nitrogen in the air, energizing them with consequent emis-sion of green and red light in ghostly arcs, ribbons and patches, moving, sometimes remarkably rapidly, across the sky. Vigorous ‘storm’ aurorae sometimes spill down into lower latitudes (Fig. 1.15 ), and fi ne auroral displays can occasionally be seen from the southern coast of England (latitude 50° 47 ¢ N) and other northern sites. For example, there were intense all-sky displays visible from all over Europe and North America in March 1989 and August 2010, reportedly disabling satellites and affect-ing power supplies. Aurora watchers might like to note that the next solar maxima, when aurorae will be most likely, are predicted for 2013 and 2024.

The fi ve brightest planets, borrowing their luster from the Sun, cast a steadier light than stars as they weave their slow paths through the background patterns of

Fig. 1.13 Our stable star – the Sun (Photo: Sheri Lynn Karl)


the constellations of the zodiac. With a little practice, it is not dif fi cult to tell which planet is being observed.

Mercury’s bright dot, comparable to the brightest stars, is rarely seen by the casual observer, and then usually between trees or housetops (Fig. 1.16 ), as it never moves further than 28° away from the Sun as seen from Earth. It is therefore seen in a twilit rather than a really dark sky; at dawn, it will be lost to the brightening eastern glow, while at dusk, it will chase the Sun down and soon disappear behind horizon objects.

Venus’ highly re fl ective sulphuric acid clouds cause it to appear brilliantly white, and this ‘morning star’ or ‘evening star’ (Fig. 1.17 ), never more than 46° away from the Sun, can appear so uncommonly bright (up to a glittering magnitude −4.7) that it is often reported by non-astronomers as a mysterious UFO in the sky, especially if seen from a moving vehicle, as its great distance causes it apparently to ‘follow’ the observer. Try an interesting experiment: when Venus is at its most brilliant, can you fi nd an observing site dark enough to be able to verify whether Venus really can cast shadows on a light-colored surface, as many astronomers have claimed?

The iron-rich, rusty soils of Mars give it its reddish appearance, and its identi fi cation with the god of war may stem from the association of Mars’ color with that of blood, fi re and tearful eyes. On its journey around the ecliptic zone,

Fig. 1.14 The solar spectrum on a kitchen wall

19Sunlight

Mars occasionally passes ‘near’ the red giant stars Aldebaran (magnitude 0.85), and Antares (magnitude 0.96), and the planet may well be confused with either of them (Fig. 1.18 ). Indeed, Antares means, in Greek, ‘rival of Mars.’ but the planet is dis-tinguished from these stars by its steadier light.

The giant gas planets Jupiter (Fig. 1.19 ) and Saturn are visible for most of the year. Older and wiser gods, they have a more sallow, yellowish look, but they can be very bright. Jupiter may attain magnitude −2.3, and Saturn −0.3. Many observers see Saturn as somewhat dull in hue compared to its bigger and brighter neighbor, Jupiter.

Fig. 1.15 The aurora of 2000 April 6–7, from my back garden


Fig. 1.17 The evening star: Venus at twilight

Fig. 1.16 Mercury sets below the Pleiades, 1996 April 24

21Sunlight

Fig. 1.18 Mars (below centre) nears its red rival Antares in Scorpius

Fig. 1.19 Jupiter and Bob’s 21-cm/8.5-in. re fl ector


Moonlight

To demonstrate that there is no such thing as true moonlight, but merely re fl ected sunlight, simply take a long-exposure photograph (30 s to 1 min) of a landscape with a tripod-mounted camera on a clear night, when the Moon is up and is full or nearly so. The resulting photograph (Fig. 1.20 ) will be indistinguishable from a sunlit, daytime scene, with green grass and a blue sky, though the presence of stars in the sky will give the game away.

The amount of sunlight re fl ected away by the Moon is small compared with what falls on it. The albedo of the Moon is 0.07 on a scale of 0–10, representing a re fl ective capability of only 7%. Even this poor ration of night-time light was enough, however, to allow human activity to continue after sunset, beneath the Moon, before the advent of arti fi cial lighting.

As the Moon revolves around Earth, we can follow the progress of night and day on our satellite as it goes through its cycle of phases. It is surprising how many people still believe that the Moon has a permanently dark side, in spite of the fact that they can see the frigid lunar night pass slowly across the Moon’s Earthward face over a period of 4 weeks (Fig. 1.21 ).

Our ancestors venerated the Moon for a good reason. Since the dawn of the human adventure on Earth, it has provided light, for at least some of the time, at night. Bright moonlight might have made the difference between a hunter-gatherer

Fig. 1.20 Moonlight: a midnight Moon and a 20-s exposure create a daylight scene

23Moonlight

community thriving or starving in prehistoric times. In the twenty- fi rst century there are still many groups of people, remote from the world’s arti fi cial infrastruc-ture, who depend upon this light at night rather than that provided by a power company. The human eye has evolved to take advantage of this low-level night-time illumination and can adapt itself to surprisingly dim conditions in a very short time, if given the chance. The hormone rhodopsin (‘visual purple’) stimulates the cylin-drical rod cells of the retina in low-light conditions, and, if we have been exposed to bright light, we can usually achieve effective dark adaptation beneath the night sky in an unlit location within a few minutes, though sensitivity may continue to increase, especially in younger eyes, for up to half an hour.

Many modern humans, when going outside at night from their brightly lit houses, may glance at the night sky and, without giving their eyes a chance to adapt, too readily conclude that there is little to see up there even if it is reasonably dark outside. In all the millennia before the invention of bright electric lighting, the stars must have been a striking and familiar sight to people venturing out from less gen-erously lit interiors.

Fig. 1.21 The Moon at fi rst quarter, 2010 December 13. The line between lunar day and night is known as the terminator (Photo: Len Telford)


Starlight

As a fl edgling teenage stargazer in the early 1960s, proud of my cheap 3-in. refrac-tor and voraciously reading and re-reading Patrick Moore’s books, Norton’s Star Atlas and the Larousse Encyclopaedia of Astronomy , I was constantly surprised by the stars. I saw plenty of them at that time (Fig. 1.22 ) from the small Shropshire town in which I then lived.

My fi rst surprise was that the nearest star to the Sun, Proxima, turned out to be invisible, not only because it is more than 62° south of the celestial equator while I lived at latitude 52° north, but also because it is a dim red dwarf massively upstaged by its neighbor a Centauri. Yet one of the brightest of the summer stars, the blue-white beacon Deneb (Fig. 1.23 ), at magnitude +1.3, lay more than 1,600 light years away! The Romans were still marching along Watling Street 1 , their main road from Dover through London to North Wales, which passed within a few miles of my boyhood home, when Deneb’s light began its journey to my younger eyes. I was similarly surprised to fi nd that the famous Pole Star (Fig. 1.24 ) is only the 49th brightest in the sky, at magnitude +1.9.

Fig. 1.22 The Milky Way fl ows through Cassiopeia and Cygnus in a dark, rural night sky

1 According to R. H. Allen ( Star Names , 1899), the name ‘Watling Street’ is derived from the Anglo-Saxons’ Waetlinga Straet (‘Giants’ Way’). It was one of their names for the Milky Way.

25Starlight

Fig. 1.23 Deneb is the brightest star in this 3-min exposure from Child Okeford, Dorset

Fig. 1.24 The Pointers of the Plough indicate the Pole Star, high above the marquee of a school’s summer camp


This concept of stellar magnitude harks back to classical times, when the brightest stars were assumed to be the biggest (Latin magnitudo , size, bigness). The scale of magnitudes has its origins with the Greek astronomer Hipparchus, whose catalog of stars (c.140 b.c. ) is the fi rst known to divide them into orders of brightness, using terms like ‘bright’ and ‘small’. Three centuries later, Ptolemy declared in his Almagest (c. a.d. 140), which often recalls Hipparchus’ ideas, that the brightest stars would be of the fi rst magnitude, prominent but less ‘important’ ones of the second, and so on. The faintest stars visible were to be of the sixth magnitude.

All this can be rather subjective, and hardly lends itself to scienti fi c accord and accuracy, so nowadays it is agreed that a star of magnitude +6.0 will be 100 times fainter than a star of magnitude +1.0. It follows that a star of, for example, magni-tude +5.0 is 2.512 times brighter (2.512 being the fi fth root of 100) than a star of magnitude +6.0, and so on up and down the scale. The plus sign is important, since the magnitude of the brightest star in the night sky, Sirius, becomes by this reckon-ing −1.4. Still not the simplest of schemes, it serves modern astronomers well enough for them to hold on to it.

From a very dark place, some keen-eyed observers claim to see stars even fainter than the sixth magnitude, down to the seventh. A modest telescope, for example, a 75-mm refractor, will show stars down to about eleventh magnitude in a dark sky.

The starlight that we see (in a dark place, about one- fi fteenth of the light of a full Moon) is the result of nuclear transformations deep within stellar cores. During their long lifetimes, typically billions of years, stars create new elements from other, less complex ones. For example, a solar-type star will create most of its energy from the continuous crushing together in the 17-million-degree furnace of its core of vast numbers of hydrogen nuclei to make helium. Four hydrogen nuclei become one helium nucleus, a process which involves mass loss and the liberation of energy. As a result of this relentless manufacture of helium, the Sun annihilates millions of tons of its mass every second, to be dispatched into space as energy in its various forms of electromagnetic radiation.

Many of the other elements so familiar and vital to us on this planet, for exam-ple oxygen, silicon and carbon, were made by stars a little more massive than the Sun. The comparative scarcity, and resultant high price, of heavy elements such as gold – the International Gold Corporation estimates that all the gold in the world, mined and unmined, could be formed into an 18-meter cube – stem from the fact that they are created during the fi nal violent explosions of those rare stellar blast furnaces, the supernovae (Fig. 1.25 ). These stars, ending their cosmically brief lives by rapidly ejecting nearly all their mass outwards into space, are hot enough to forge the heaviest of elements. Since there is, on average, only one supernova outburst every century in any one galaxy of a hundred billion stars, gold is in short supply in the universe.

The most recent supernova visible to the unaided human eye was discovered on February 24, 1987, about 160,000 years after its eruption in the Large Magellanic

27Starlight

Fig. 1.25 Supernova 1993J in M81 (NGC 3031)

Cloud (LMC), by Ian Shelton at the observatory of Las Campanas in Chile. The once lowly tenth-magnitude star Sanduleak −69 202, suddenly the most famous object in the sky, eventually peaked as SN1987A at an apparent magnitude of +3. The LMC is a satellite galaxy of the Milky Way, and the last naked-eye supernova inside our galaxy was recorded by Danish astronomer Tycho Brahe in 1604. We are well overdue for another. The red giant star Betelgeuse, about 640 light years dis-tant in Orion, is said to be worth watching. It may not have long to go, in stellar terms, before its fi nal paroxysm. If humans observe this, it may well be visible in broad daylight and outshine the full Moon at night.

Occasionally, an unexpected nova (Fig. 1.26 ) reaches naked-eye visibility. The nova will not have the éclat of a supernova, but may be bright enough for its progress to be monitored with the naked eye or with modest optical aid for a few days or weeks, fi nally disappearing again from view. In spite of their name, novae are old stars rather than new ones, members of aging binary systems in which a white dwarf star has material ‘dumped’ upon it by a larger companion.

A clear view of the stars led, in ancient times, to their being grouped into con-stellations. Two thousand years ago, Ptolemy of Alexandria listed 48 constellations from former times. Today, 88 constellations mark out the heavens, serving as a convenient naming and reference system. It should be remembered that those con-stellations so familiar to European and American astronomers may baf fl e their


brethren in the Far East, for example, where completely different nomenclatures have evolved. Cave art at Lascaux in France suggests that, as far back 17,000 years ago, people were imagining pictures in the sky. Groups of dots around one of the famous painted bulls unmistakably represent the Pleiades and Hyades star clusters in Taurus, and Orion’s Belt, arranged as in the real sky (see www.mazzaroth.com/ChapterOne/LascauxCave.htm ). About 5,000 years ago, the Sumerians and the Egyptians had already established their traceries of creatures, symbols and heroes in the sky (Fig. 1.27 ).

On a clear night, with a simple chart and a good imagination, we can try to retrace the thoughts of the ancients as they found their way around the night sky, which served them as clock, compass, calendar and oracle, and as a scienti fi c and religious primer. The constellations have kept their identities over the millennia, and their number has gradually increased, facts that bear witness to the continuing fascination which the sight of the starry sky exerts over humans, and to our need to observe and interpret what we see in the environment above us.

Fig. 1.26 Nova Aquilae 1999 December 4. The ‘new’ star is near Delta Aquilae, and is arrowed on the accompanying chart. Altair is the brightest star at the top of the photo

http://www.mazzaroth.com/ChapterOne/LascauxCave.htm

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29The Zodiacal Light

The Zodiacal Light

A common sight in a starry, moonless sky as seen from the countryside, before wasted light from distant cities and local lamps began to intrude, was the zodiacal light. This manifests itself as a faintly glowing cone, slanting upwards from its base along the horizon, seen to the east shortly before dawn or to the west shortly after dusk (Fig. 1.28 ). Only in a few dark places can it now be well observed. Brighter than parts of the Milky Way, it is best seen when the ecliptic, along which its axis lies, stands nearly vertical to the horizon in spring or autumn.

This ghostly light is due to the scattering of sunlight by vast numbers of dust grains which litter the Solar System, many left behind by passing comets. Giovanni

Fig. 1.27 An ancient constellation: Orion, the Osiris of the Pharaonic Egyptians (Photo: Chris Bowden)


Cassini was the fi rst to realize this, in 1683. The particles involved are mostly between 0.1 and 0.2 m m in diameter and tend to be concentrated in a lens-shaped cloud, centered on the Sun and aligned with the plane of the planets’ orbits. This explains why the zodiacal light stretches along the ecliptic.

The Gegenschein

In an extremely dark sky, such as might be seen nowadays only from locations remote from population centers, a faint circular glow may be perceived with the unaided eye in the night sky opposite the Sun (the anti-solar point). This is the Gegenschein (German for ‘counter-glow’), and an excellent illustration of it is on http://apod.nasa.gov/apod/ap990625.html .

Gegenschein is caused by the back-scattering of sunlight from tiny dust parti-cles. It is a rather similar phenomenon to the ‘glory’ sometimes seen by air travel-ers, a ring of light around the shadow of the aircraft in clouds opposite the Sun.

The cosmic light that falls from the moonless dome of stars may not necessarily be bright, though to the dark-adapted eye it can be surprisingly effective in reveal-ing one’s surroundings. The French playwright Corneille testi fi ed to this in Le Cid , written in 1637, long before the era of all-night arti fi cial lighting. In the fourth act of the play, Don Rodrigo (the Cid) spies the approaching Moorish battle fl eet by starlight, ‘ cette obscure clarté qui tombe des étoiles ’ (that faint light that falls from the stars).

Fig. 1.28 The zodiacal light from La Palma (Photo: Alan Drummond)

http://apod.nasa.gov/apod/ap990625.html

31The Gegenschein

Today, as the twenty- fi rst century gets under way, the night’s natural light, emanating from a variety of sources and even indirectly from the Sun, has been erased and veiled as never before in human history (Fig. 1.29 ). The last 60 years have seen the stars go out for much of the world’s population. It does not require much investigation to know why.

Fig. 1.29 Veil across the heavens – light pollution blots out the southern stars


Light Pollution: The Problem De fi ned

Chapter 2

Lights and More Lights: The Rise of Arti fi cial Illumination

Since early humans sought the reassurance of their wood fi res and tallow lamps many thousands of years ago, manmade light has been seen as our friend. It allowed its creators to see and perhaps frighten off the approaching predator, to go about their domestic business after sunset, and to paint images of great power and beauty in the silent fastness of caves. The precious light meant that they could share their thoughts, plans and opinions by night as well as by day. These were times when facial expression and gesture were important reinforcements of emerging lan-guages. Nights were dark and the sky full of mysteries, and later in the human story, those who could calculate, predict and give meaning to the easily seen yet mysteri-ous cycles and phenomena of the night sky became priests and leaders. Some of their durable stone sky-markers still stand. Nowadays, these may be mere tourist attractions, but in the days of their creators they formed foci for settlement and assembly, during humankind’s long transition from hunter-gatherer groups to more static and structured communities.

For many thousands of years thereafter, villages slumbered in the darkness of our planet’s night, with the occasional candle or burning animal-fat torch to cast a modest glow. Surprisingly little progress was made in the design and construction of lamps between the time of the ancient Sumerians ( c. 3000 b.c. ), whose hollow-stone, shell and pottery lamps (Fig. 2.1 ) have been unearthed from the ruins of Ur, and the eighteenth century, when oil or grease burning from a wick still lit human dwellings. Even at the beginning of the nineteenth century, the Eddystone Lighthouse’s candle-power was literally just that.

34 2 Light Pollution: The Problem Defined

Sleep patterns followed the day-night rhythm more closely, and people slept longer in the past – 9 h, before the invention of the tungsten fi lament bulb, com-pared with today’s seven and a half hours, according to Stanley Coren ( Sleep Thieves , 1996 ) . The nineteenth century saw the transition from oil lamps to gas lamps and fi nally to the fi rst electric lighting, with the growth of systematic if com-paratively dim street lighting (Fig. 2.2 ) augmenting the human eye’s attempts to fathom the gloom.

Sporadic attempts to light streets had been made in earlier centuries. For exam-ple, in Paris, in 1367, regulations existed requiring lanterns to be hung in streets,

Fig. 2.1 Stone and shell oil lamps (Courtesy SSE Museum of Electricity, Christchurch)

Fig. 2.2 A bulky carbon arc streetlamp from the 1880s next to the surprisingly small original fi lament lamp by Swan (Courtesy Eric Jones, SSE Museum of Electricity)

35Lights and More Lights: The Rise of Artificial Illumination

and in 1415 the mayor of the city of London ordered that all dwellings along the highway should provide an outside lantern every night between All Hallows’ Eve (October 31) and Candlemas (February 2). Exceptions were made for the nine nights after the Moon had passed its fi rst quarter, the period when, according to the encyclopaedist Krunitz, “the grand light that rules the night can light the street suf fi ciently, and lanterns are super fl uous.” In 1588, with the fear of Spanish incur-sions fi rmly in the public mind in England as the Armada sailed up the Channel, an order was made requiring city householders to provide outdoor lamps. The penalty for disobeying this edict was death, though, after the passing of the Spanish threat, compliance was much reduced by the substitution of a fi ne of one shilling.

The fi rst attempts at large-scale gas illumination in several countries were due mostly to the efforts of William Murdoch in 1779. It was well into the nineteenth century before puri fi cation of the gas and better burner designs led to an incan-descent gas lamp (invented in 1885 by Austrian Carl Auer von Welsbach), which gave light from the heated mantle rather than from the luminosity of the fl ame itself, but this system could still not be considered a very bright source. Arc lights, demonstrated by Sir Humphrey Davy early in the nineteenth century, fell out of favor for most applications because of their unreliability, need for high maintenance and short lifetime. Their somewhat harsh light made them unpopular when used in city streets. As cheaper, longer-lasting incandescent bulbs became available at the end of the nineteenth century, arc lights were no longer seen in streets, but lingered on in industrial areas and as theatre spot lamps.

It was an English physicist and chemist, Sir Joseph Wilson Swan, and an American physicist and inventor, Thomas Alva Edison, working independently, who sealed the fate of humanity’s natural nights. In 1878 they perfected, almost simultaneously, bright incandescent- fi lament lamps, enclosed and powered by elec-tricity. Swan fi rst demonstrated his lamp (Fig. 2.3 ) to the Newcastle Chemical Society in December 1878. Within an elongated bulb, he had surrounded the incan-descent carbon fi lament with an almost perfect vacuum, the fruit of his collabora-tion with C. H. Stearn, who was working on the creation of vacua with the aid of an expert glassblower, Frederick Topham.

In the United States, Edison had also been working on a fi lament lamp. He experimented with all manner of fi laments, including carbonized cotton, and bam-boo, specimens of which he had explorers send to him from all over the world. Edison produced a lamp in October 1879 which worked for 45 h. After a period of rivalry, Swan and Edison sensibly pooled their ideas and resources, and the Edison and Swan (later Ediswan) United Electric Light Company was formed in 1881.

When electric lighting is mentioned, most people will have in mind the descen-dant of the nineteenth-century Ediswan bulb: the incandescent tungsten- fi lament lamp, on ceilings across the electri fi ed world. This is now being replaced in its turn by more modern, compact fl uorescent (CFL) types, often referred to as “energy-saving” bulbs, and LEDs (light-emitting diode lamps). Incandescent lamps were the light source of choice for street lighting until the advent of high-intensity discharge lamps. Mercury and sodium discharge lamps, within which gas is excited to glow-ing by electrons passing through, swept fi lament types away in the 1930s, thanks to their even longer life expectancy and greater ef fi ciency. Denis Crow, former curator


of the CU Phosco Museum of Street Lighting, made the interesting point that “with oil, wax, gas and fi lament lamps, light was a by-product of heat, whereas with dis-charge lamps, the opposite argument could be made.”

The original mercury discharge lamps, dating from the early 1930s, gave between two and three times as much light as equivalent fi lament lamps; and the sodium vapor discharge lamp, which researchers at Eindhoven in Holland did much to improve, gave four times as much light. The negative characteristic of discharge lamps, though, is that they require auxiliary gear to help start them, control current and improve the power factor.

The twenty- fi rst century has seen an upsurge in the use of bright, usually white sources such as metal halide, CFL and increasingly, LED lamps. The latest tech-nologies involving LEDs, or induction lights, where energy is transferred through the glass envelope by electromagnetic induction, emit a white light that provides high illumination for lower wattages.

Fig. 2.3 Bob with a replica of Swan’s fi rst fi lament lamp (Courtesy SSE Museum of Electricity)


Today, high-intensity discharge street lights are still very much in evidence, but in some countries a revolution in road lighting has occurred in the last few years, as the pinkish-orange glow of high-pressure sodium (HPS) lamps is superseded by the white light of metal halide and other types. Such lamps provide the greatest photopic illumination for the least electricity consumed.

Lighting professionals have acknowledged the role of dark-sky campaigners in accelerating this process, though the latter, as well as many residents of the streets where they have appeared, have expressed concern at the increased brightness of the new sources compared with those they replaced. “Floodlit” bedrooms and light re fl ected from the ground into the sky are a high price to pay for illuminated streets.

The gradual, and undoubtedly popular, spread of public outdoor lighting across the developed world has proceeded at an ever increasing rate since the nineteenth century. Great efforts have been made by many clever people to improve the quality and ef fi ciency of the lamps, whatever the light source employed, in order that those who wish to venture out at night have an evenly lit environment, and can discern the nature and color of the objects within it. One aspect of lighting design, however, the “poor relation” for most of that time, was directionality (Figs. 2.4 and 2.5 ).

Fig. 2.4 Poorly directed emissions: much of the light misses the church


The unquestioning approval the blessings of early street lighting inspired in our forebears became a habit. Before the late 1980s few people were ready to condemn the excesses of overlit and garish surroundings, assuming perhaps that the discom-fort caused by glare was normal, the inevitable result of a lit environment at night (Fig. 2.6 ). As the stars began to go out, magnitude by magnitude, over great cities and smaller towns; as bedrooms began to be fi lled with light even with their cur-tains closed; and as the fi rst of the legions of “Rottweiler” domestic and industrial fl oodlights began to bite in both town and countryside, ousting the traditional more modest and welcoming porch light, little protest was made – the uncomfortable cost, perhaps, of progress (Fig. 2.7 )?

What will be the future of lighting? The new technologies of remote control and energy optimizing will spur great changes. Lights across wide areas will be con-trolled by individuals sitting at computer keyboards, aided by sensors and imaging systems. There will be great changes in the way we light our public spaces. Appendix 4 gives a professional’s view.

For countless years, on every clear night, human beings have been able to behold the spectacle of the starry heavens, spangled with thousands of stars and traversed by the Milky Way. Nature’s grandest free show has spurred us to consider our place in the great scheme, has given rise to many themes and aspects of our religions and cultures, and has inspired both artistic achievement and scienti fi c endeavor.

Fig. 2.5 Shielded light in a supermarket car park, preventing light spill into houses

http://dx.doi.org/10.1007/978-1-4614-3822-9_BM1


Fig. 2.6 Glare dominates the environment in this photo taken on the outskirts of London (Photo: Edward Hanna)

Fig. 2.7 Most of the light from this car park fl oodlight will go into the sky (Photo: Mike Tabb)


The unspoiled starry sky is, unof fi cially but undeniably, a site of special scienti fi c interest, and an area of outstanding natural beauty. Now, ill-directed arti fi cial light has quietly stolen it away from many people in the developed world. What is the real nature of light pollution? Does it impact only on astronomers? How can it be quanti fi ed?

Skyglow

Skyglow is light that is being carelessly, or sometimes deliberately, projected from the ground or a structure, coloring the night sky and reducing the visibility of astro-nomical objects. The Royal Commission on Environmental Pollution compared it in its 2009 report Arti fi cial Lighting in the Environment to “a cloud of… visually impenetrable, arti fi cial vapour.” It should not be confused with airglow, a word sometimes used for the very faint luminescence ever-present in the night sky due to the Sun’s radiation re fl ected from, or energizing, particles both within and beyond the atmosphere.

The cause of skyglow is nowadays well known. Upward light (especially travel-ing at low angles) from poorly designed lamps (Fig. 2.8 ) is scattered and re fl ected by aerosols in the atmosphere. It returns to the eyes of Earthbound observers, so paradoxically it is light coming downwards that causes skyglow! In areas where this is permitted to occur, some or all of the detail of the night sky may be lost.

Fig. 2.8 The massed and mostly poorly directed lights of Canford Heath, Dorset

41Skyglow

Fig. 2.9 Skyglow over Poole: the “hot spot” is caused by the fl oodlights of the cross-channel ferry terminal

The effect is not always localized, as the glow above a distant large town (Fig. 2.9 ) will color the sky for an observer tens of kilometers away.

It is almost never the deliberate intention of the owner of the light source to illuminate beyond the boundaries of the premises in which the source is located. The enormous amount of wasted light we see around us is the product of ignorance as well as of poorly designed luminaires. Before about 1950, where street lighting existed, it was a common practice to turn the lights off at about midnight. The rela-tively small numbers of luminaires in towns and cities meant that, although their designs often allowed emissions to escape above the horizontal, it was usually pos-sible to appreciate the night sky from many places in town, even when lights were on (Fig. 2.10 ). This may have involved a short walk, but, in those days, when walk-ing was a far more readily undertaken activity, and fear of crime had not begun the climb to its present in fl ated level, this would have seemed acceptable.

Now, as the twenty- fi rst century enters its second decade, the number of street lights in Europe has reached approximately 90 million, of which seven and a half million are in the UK (Fig. 2.11 ); in the United States and Canada, there are more than 20 million road lights. Most areas of large cities are intensively illuminated, with growing numbers of lights along the roads between those cities. Town dwellers vacationing in the countryside are often surprised by the fact that some villages are nowadays as brightly lit at night as their main streets at home; and the high-powered security lighting of nervous cottage-holders winks on and off just as much as it does on the urban scene. A principal reason for this is that many of these settlements now


have populations composed mostly of ex-“townies,” who are happy to sacri fi ce their new and unaccustomed view of the night sky for the easy, debatable reassur-ance of the urban street furniture they have left behind. Wasted light in the country-side, which journalist and broadcaster Libby Purves described in Town and Country (1999) as “this rural plague” (Fig. 2.12 ), means that, even far away from big towns, children are now growing up with no opportunity to see the Milky Way, or much detail in the starry sky.

Fig. 2.10 The city of Bath by night, 1950s and 2000 (Photo: Mike Tabb)

43Skyglow

Fig. 2.11 Some of the large numbers of new, downward-directed road lights replacing old wasteful types in the UK

In regions or countries where population centers are fairly close together, for example along the eastern seaboard of the United States, in Belgium, Holland and the United Kingdom, it is possible to travel at night for long distances in nominally “rural” areas without ever escaping strong skyglow from chains of towns and large villages nearby. The skeins of waste light are obvious on satellite images of Earth at night (Fig. 2.13 ). Even the smallest village may have a sports facility that fl oodlights the surrounding area to a considerable distance, and isolated farms and cottages may be lit with lamps that spread their glare across a far greater area than intended (Fig. 2.14 ). In areas where it is possible to be hundreds of kilometers away from towns, such as in the outback of Australia, cones of light from distant conur-bations may still taint the sky along the horizon.

On a very local scale, a poorly aimed domestic “security” light with a typically excessive wattage of 300–500 W (what Libby Purves once christened “the Rottweiler light”), will make observation of the night sky dif fi cult, if not impos-sible, for an observer tens or sometimes hundreds of meters away (Fig. 2.15 ). A fl oodlit golf driving range, like the one that has compromised the stars over Stonehenge (Fig. 2.16 ), can create a pall of light visible from a great distance.


Fig. 2.13 Europe by night (Copyright 1996 W.T. Sullivan and Hansen Planetarium)

Fig. 2.12 Urbanisation of the countryside near John O’Groats (Photo: Bill Eaves)

Fig. 2.14 A farm light shines into a neighbouring garden (Photo: Graham Bate)

Fig. 2.15 Warrington, Cheshire: a car lot’s “security” fl oodlight intrudes into premises well outside its perimeter (Photo: Ian Phelps)


Fig. 2.16 Looking towards Stonehenge from the east, 2011: a golf range steals the ancient stars (Photo: CfDS)

The night sky over one of Britain’s newest national parks, the New Forest, is tainted by a golf facility well outside its boundaries. Add to all this the inappro-priate use of very bright lights to illuminate relatively small areas, fashionable “light art” displays, and the fact that lights are often left on when there can be nobody around who might conceivably need the light or appreciate its effects, and the extent of the problem becomes apparent.

In the UK, in 1991, the CfDS carried out a national survey of over 200 astro-nomical groups. This included a questionnaire to be distributed to group members, asking for details of their location, and of the visibility of the night sky from it. Respondents were well scattered, some observing from great cities, and others from small towns, villages or isolated rural locations throughout the country.

Of 805 observers, from the casual to the assiduous, who responded, 727 (90.3%) stated that skyglow was visible to some extent in their night sky at home. The great majority (701) of these 727 “positive” respondents commented on the degree of severity of the effect of skyglow on astronomical observations. A total of 211 described it as “noticeable.” 453 as “strong,” and 37 reported having given up observ-ing the night sky altogether because of “impenetrable” skyglow. The conclusion

47Skyglow

drawn by the CfDS was that more than 90% of people who wish to see the night sky in the UK, and they are certainly not all amateur astronomers, probably suffer from light pollution at least noticeable enough to hinder observation. Well over half of these would-be observers have to contend with considerable skyglow. Further details of the survey may be found in the Newsletter of the BAA Campaign for Dark Skies , Spring 1992, page 2 ( www.britastro.org/dark-skies ).

More recent surveys were carried out in 2007 and 2009 during the national Star Count weeks organized by the CfDS and the Campaign to Protect Rural England (CPRE). Thousands of people all over the UK went outside to see how many stars they could count in the constellation of Orion (within the rectangle of his four brightest stars) on selected moonless nights. The results showed that only 8% of participants could see more than 20 stars. Three in fi ve people (59%) taking part could see just 10 or fewer stars within Orion, indicating severe light pollution, and just 1% of people had truly dark skies, reporting 30 or more stars.

Collaboration between the CfDS and the National Remote Sensing Centre led to the publishing in 1991 of the now well-known satellite image of a cloud-free UK by night, revealing the extent of light pollution across the country. Similar images of many areas of the world (Fig. 2.17 ) have been produced by the team led by Professor Woody Sullivan, of the Astronomy Department of the University of Washington (Seattle, WA).

How many stars does skyglow take away from us? A pristine dark sky, as seen by an exceptionally keen-eyed young observer, may offer as many as 7,000 naked-eye stars down to magnitude 7 (see Chap. 1 , “Starlight”). Table 2.1 shows the dra-matic reduction in the numbers of naked-eye stars as they are lost, magnitude by magnitude, to wasted light.

Fig. 2.17 The lights of the world by night, from space (Copyright 1994 W.T. Sullivan and Hansen Planetarium)

http://www.britastro.org/dark-skies

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The term “light pollution” also covers terrestrial light intrusion problems. De fi nitions of terrestrial light pollution abound in the literature. Is it only intrusive light into bedrooms? Is it the degradation of the ancient and mystical experience of the night in rural areas? Is it the garishness of a city center at midnight? Or is it, as some campaigners have proposed, the introduction by humans, directly or indi-rectly, of any arti fi cial light into the environment? Opinions will always differ. There is, however, a broad consensus on its astronomical sense: it is the veiling effect upon celestial objects of light emitted with an upward component from local or distant luminaires (an unusual word to some – see Glossary ).This wasted light does not have to be emitted vertically to cause skyglow. In fact, light traversing a path at a shallow angle (up to 10°) above the horizontal from a luminaire will cause considerably more skyglow, since it will encounter many more particles and drop-lets from which to be scattered on its way through the atmosphere. This interesting conclusion is discussed at length in Dr. Chris Baddiley’s important paper Towards “Understanding Skyglow” (see Bibliography ).

Turning the Tide

In 1988, in the United States, the International Dark - Sky Association (IDA), whose founding members include David Crawford and Tim Hunter (Fig. 2.18 ), took up arms against skyglow. The IDA now has several thousand members, with branches and af fi liated organizations in many countries. In 1989, the council of the British Astronomical Association (BAA), the UK’s largest body representing the interests of all who wish to observe and enjoy the sky at night, discussed and authorized the setting up of a Committee for Dark Skies, later to become the Campaign for Dark Skies (CfDS, Fig. 2.19 ). The CfDS maintains close links with other like-minded organizations around the world. The time had come, it was felt, to call a halt to the rising tide of waste light in the night sky, and these organizations set themselves the daunting task of not just halting but reversing that tide.

Since that time, similar movements have been founded in many countries (see Appendix 2 of this book). Annual meetings where campaigners from around the

Table 2.1 Numbers of stars seen at various limiting magnitudes (Source: IDA)

Limiting magnitude Number of stars seen (faintest star visible)

+7 ~7,000 +6 ~2,500 +5 ~800 +4 <250 (Milky Way no longer visible) +3 <50 +2 <25

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49Turning the Tide

Fig. 2.18 Tim Hunter ( left ) and David Crawford, founders of the IDA (Courtesy IDA)

Fig. 2.19 The committee of the Campaign for Dark Skies, 2011: left to right , Chris Baddiley, Mike Tabb, Bob Mizon, David Paul, Martin Male, Tom Webster, Graham Bryant (Absent: Darren Baskill, Stuart Hawkins, Martin Morgan-Taylor)


globe gather to discuss progress and strategies are held in many countries. These include IDA conventions, European symposia, and special events such as the International “StarLight” Conference in 2007 in La Palma, Canary Islands (see Appendix 1 of this book).

The inescapable irony behind light pollution is that, while trying to ensure a more welcoming and easier outdoor night-time environment through lighting tech-nology, we often lose sight of the near and far universe, which is being revealed to us in more and more detail almost daily by technologies of another kind: those of spacecraft and imaging. A kind of virtual-reality mask is replacing our real experi-ence of that half of our environment arching above the horizon.

One of the things that nearly everybody “knows” about Earth as seen from space is that, if an alien craft ever approached this planet, one of the fi rst signs to the crew of our tenure on it would be a view of the Great Wall of China, commonly said to be the only artifact of humankind visible from outer space. In fact, the wall is not seen from above our atmosphere, as astronauts have con fi rmed, being a surprisingly narrow and mostly ruined structure, not strikingly different in color from its sur-roundings. The wakes of ships, plumes of steam from power stations (Fig. 2.20 ) and similar extended objects contrasting strongly with darker backgrounds, are more

Fig. 2.20 The diffusion of power station and factory steam plumes is striking in this Landsat image of the north-west Midlands of England, taken from an altitude of about 900 km/560 miles (Copyright Focal Point A-V, Portsmouth)

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51Turning the Tide

likely to be seen from above the atmosphere than the wall. However, as our hypothetical visitors rounded the night side of Earth, what they would easily see, spread across the darkness, would be the chains and patches of light, by no means all re fl ected from the ground, thrown up from our towns and cities, road networks, sports and industrial installations, and countless other sites. Then they would know for certain that the planet is inhabited by technologically minded beings, though the energy that we so visibly waste would be likely to count against us in the minds of these advanced observers.


Adverse Impacts of Inef fi cient Arti fi cial

Lighting

Chapter 3

Anyone discussing the adverse effects of poorly aimed and over-bright lighting would do well to concentrate on those aspects most likely to interest the audience. Not everybody feels the urge to study the night sky, but just about everybody wants to know whether their money is being wisely spent, and how energy can be conserved and not wasted. There are also less obvious but equally important aspects of the lighting debate, for example, impacts on health and wildlife, which are continually being revealed in ever greater detail.

The adverse impacts of poorly aimed and over-bright lighting are:

Waste of energy and money • Environmental degradation: skyglow, glare, intrusion • Impact on wildlife • Human health issues (dealt with in Chap. • 4 )

Waste of Energy and Money

How much energy is wasted by light pollution? How much money? Can this even be calculated? It is certainly dif fi cult to calculate, and there are almost as many estimates as there are light pollution websites. Ever-changing energy prices and currency in fl ation rapidly invalidate these estimates anyway.

As long ago as 1993, the Campaign for Dark Skies, using data for numbers of streetlights, the amount of light emitted above the horizontal by then typical lamp types, and 1993 energy costs, calculated that £53 million was wasted skywards annually by Britain’s streetlamps alone (Fig. 3.1 ). A more modern and wider-ranging fi gure is that arrived at by Andrej Mohar and colleagues of Dark Sky

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54 3 Adverse Impacts of Inefficient Artificial Lighting

Slovenia (DSS): in the publicity material for the Seventh European Symposium for the Protection of the Night Sky in Bled, Slovenia, 2007, we read: “Why does nobody care about 1,700 million Euros ‘glowing to waste’ over Europe annually, based on a conservative estimate by DSS using energy prices for 2007 and on ground and satellite monitoring?” Perhaps the real fi gure is nearer 1 billion Euros, or 2 billion Euros Europe-wide.

All that we can state without fear of contradiction is that waste light represents a costly drain on every developed nation’s resources. The International Dark-Sky Association (IDA, www.darksky.org ) reports that about one-third of all lighting in the United States is wasted by being directed where it is not needed. The annual cost of this waste to Americans, says the IDA, amounts to approximately 30 million barrels of oil and 8.2 million tons of coal, costing the country in the region of $2 billion a year.

Perhaps Andrej was wrong in assuming that nobody cares about wasted light. As energy costs rise, there are ever-increasing numbers of people who do care about this problem. For example, some French citizens are taking direct and quite visible action against light-energy waste. Consider the activities, for example, of the various branches of the Clan du Néon – the Neon Clan. They are a growing phenomenon in France, and now have chapters in other countries ( www.timesonline.co.uk/tol/news/world/europe/article5110640.ece ). Their mission: to turn off illuminated signs left on all night. In France, every neon sign has an outdoor switch, for fi re safety rea-sons. Clan members tour towns in the small hours, using poles to switch signs off. The practice, they claim, is not illegal, and saves a lot of money and energy.

Fig. 3.1 Wasted light from UK streetlights: Portsmouth (Photo: Ron Arbour)

http://www.darksky.org

http://www.timesonline.co.uk/tol/news/world/europe/article5110640.ece

http://www.timesonline.co.uk/tol/news/world/europe/article5110640.ece

55Waste of Energy and Money

The Tours (Indre-et-Loire) branch of the Clan du Néon write of themselves:

During the night, in the retail area of Tours, we see, everywhere, signs which have been left lit, but on shops which have already closed. What is the point of these signs? Are they supposed to make the place look more attractive? Or announce the continued presence of the shops? Or impose some brand or identity? First of all, illuminated shop signs left on all night long represent an unwelcome trend in ‘supplementary advertising’. Also, going beyond this idea of being ‘got at’ by publicity, what shop-owner really believes that lit neon signs in almost deserted streets will somehow boost sales?

Because we should be working for the environment and drawing the public’s attention to disastrous aspects of the consumer society, we are carrying out non-violent and damage-free action against illuminated signs… (author’s translation).

…ordinary citizens, very few of whom are astronomers, making their point about our too casual acceptance of light-energy waste. Just one of many examples of an increasing feeling among the general public that it is time that such obvious energy waste should be addressed (Fig. 3.2 ). Managers of of fi ce blocks are taking it upon themselves to enforce a strict lights-out policy when staff leave at night. Internationally, ‘Earth Hours’ and city-wide ‘save-energy hours’ are becoming more widely observed.

Fig. 3.2 City lights left on in the small hours of the morning (Photo: Darren Baskill)


Estimates of the fraction of world energy use represented by lighting vary greatly. About one-quarter is a commonly quoted fi gure.

The Energy Gap, as the gulf between demand and resources is often called, is coming. In 20 years’ time, according to a recent BBC report, lights could be going out permanently all over the UK. Trouble-free, relatively low-cost energy genera-tion is no longer something we take for granted. Surprising, then, that a recent UK Government Energy White Paper suggested that no new nuclear power stations will be built in the foreseeable future. Alternative energy sources from wind and waves are not being encouraged as much as might be expected.

However, before we invest all our faith in alternative sources, we need to cut down on the energy that we use, and waste, through inef fi cient lighting, heating, etc. In all developed countries, the most visible aspect of energy waste is that of night-time lighting. Yet right now, in the twenty- fi rst century, when awareness of the need to prevent waste climbs ever higher up the environmental agenda, we still see new lights being installed that:

1. Are too bright for the purpose; 2. Shine into places where their emissions are not needed; 3. Are, in many locations, simply unnecessary.

Figures for energy waste in the USA appear above on page 54. Bearing in mind that its population is about one-fifth of that of the USA, how much energy is thrown away in the UK every year by light-energy waste (Fig. 3.3 )?

Fig. 3.3 Wasteful design in a street light: high-pressure sodium lights illuminate the chimneys above them (Photo: Chris Baddiley)

57Waste of Energy and Money

Martin Morgan-Taylor (Department of Law, de Montfort University, Leicester) is recognized as Britain’s leading expert on light pollution and the law. He is the author of several learned articles on the subject. In the course of his work he has investigated the carbon cost of wasted lighting nationally, and fi nds that there are no formal UK government estimates of the amount wasted. DEFRA, the UK government’s environment department, published a response in January 2008 to the UK Royal Commission on Environmental Pollution, which had issued a consulta-tion document on its survey The Impacts of Arti fi cial Light in the Environment . DEFRA stated (page 2), under the title “Climate Change”:

DEFRA believes that a reduction in the amount of arti fi cial light will have both direct and indirect bene fi ts for the environment. Less light means a direct bene fi t of a reduction in emissions, helping us to achieve the goals we are setting our-selves. The Government, via its Market Transformation Programme, is currently consulting on ef fi ciency standards for lighting products and the associated car-bon savings that improvements can deliver: these can be found at www.mtprog.com/whitepaper.aspx .

Using the following DEFRA fi gures, Martin comes to an interesting conclusion:

Total UK electricity demand (domestic): • 112.61 TWh/year (T = tera = 10 12 = 1 million million); Electricity use per household in the UK, for lights and appliances, 2006: • ~3,000 kWh/year (DEFRA Domestic Energy Fact fi le – this document does not separate these two uses). Number of UK households: 25,285,000 (Of fi ce of National Statistics). • Therefore, electricity used by totality of households in the UK • for lights and appliances :

74.658 TWh/year

Separating lights and appliances is dif fi cult. The Government’s Market Transformation Programme (MTP) estimates that lighting in the domestic sector in the UK uses around 17.2 TWh/year, which means that appliances account for 57.45 TWh/year. To put these into context, a 1 GW new nuclear plant, operating at baseload, would provide around 7.45 TWh/year.

So, to produce the annual electricity required by lighting in the domestic sector requires the output of approximately 2.5 nuclear power stations (after taking account of transmission and distribution losses of around 8%).

Using the average carbon factor for electricity in 2006 (0.527 kgCO 2 /kWh), the

CO 2 emitted from domestic lighting in 2006 is estimated as 9 MtCO

2 (9 million

tonnes CO 2 ). The CO

2 emitted from domestic appliances is estimated at 30.3 MtCO

2 .

The MTP fi gure for electricity use for commercial lighting in 2006 is 49.79 TWh/year, out of a total commercial electricity demand of 259.8 TWh/year.

The MTP also estimates the electricity used for street lighting in the UK in 2006 as 2.53 TWh/year. The carbon emissions associated with this are of the order of 1.1 MtCO

2 /year.

http://www.mtprog.com/whitepaper.aspx

http://www.mtprog.com/whitepaper.aspx


Therefore, if an estimated one-third of lighting energy is wasted through unnec-essary and poorly directed lights, and lights left on when not needed, the UK is throwing away one-third of:

[17.2 TWh (domestic lights) + 49.79 TWh (commercial lights) + 2.53 TWh (road lights)].

That is, 23.17 TWh/year (i.e. 23.17 million million Wh).

Domestic Floodlights

Martin has further estimated that energy and carbon waste from 500 W consumer ‘security’ fl oodlights (Fig. 3.4 ) alone (leaving aside less powerful lamps) is between 26.5 million and 106 million kg of CO

2 per annum. Why such a large range in the

estimate? There are no published fi gures concerning the number of 500 W con-sumer fl oodlights in the UK, and for how long they are switched on.

We can, however, calculate thus: there are 25 million dwellings in the UK. Generating 1 kWh of electricity produces on average, in the UK, 0.527 kg of CO

2

(based on a DEFRA statistic).

Fig. 3.4 A poorly mounted “Rottweiler” light which illuminates premises across the street

59Road Lights

As a result, if 5% of homes have such a light, and it is on for 15 min a night (assuming the use of infra-red switches triggering the light when, for example, pedestrians or cats walk by), then the carbon dioxide produced as a by-product from producing the electricity needed to power UK domestic fl oodlights is 26,448,812.5, or 26.5 m kg per year (if 1 kW-h of energy creates 0.527 kg of CO

2 ).

The energy cost will be (1.1 m × 0.5 kW) × 0.25 h per night = 137,500 kW-h per night. Per year, the fi gure is 137,500 × 365 = 50,187,500, or 50M kW-h per year. The cost, if energy were only 10p per kW/h, would be £5 million.

The fi gure is 53 m kg of CO 2 if 5% of households have the light on for 30 min a

night, or if 10% of households have the light on for 15 min a night (£10M at 10p per kW/h).

The fi gure is 106 m kg of CO 2 if 10% of households have a light on for half an

hour each night (£20M at 10p per kW/h). An interesting statistic: a 100 W bulb left burning through all the hours of darkness in a year causes about half a ton of carbon dioxide to be emitted by the power station, according to a lighting industry source.

The variance highlights the need for a detailed study to settle the matter. If there is twice the lighting wattage power consumption for the commercial/

public sector fl oodlights used in the UK (excluding street lights), and these are on all night long, then the economic cost of the waste would be c. £480 million, assum-ing a 50% waste factor from over-lighting, lighting empty and unused car parks. There is obviously a clear need for public education and planning guidance over such a potential level of power consumption and waste.

Although the current trend is for the use of energy-saving light fi xtures within the home, it is certainly worth insisting to any agency encouraging this trend that they must not forget the lights outside the house, which can often be much brighter and more wasteful than any indoors. Indeed, cash-strapped city councils are increasingly trying to save money by reducing energy expenditure (see Chap. 5 ).

Road Lights

There are many estimates (see above) of the amount of energy wasted by poorly directed road lights. The website Starry Night Lights ( www.starrynightlights.com ) sums up the dif fi culty of arriving at any kind of accurate fi gure, stating that upward light “wastes billions of dollars annually in the United States: $5–$10 billion depending on whose numbers you want to use.” In some places, energy is now being more ef fi ciently used along road networks. Road lighting has for some years now shown a trend towards better direction (Fig. 3.5 ), but over-bright lamps con-tinue to be installed in some places as whiter light sources gradually replace their orange (sodium) predecessors.

A remarkable development in the UK over the last 4 years is that large numbers of local authorities are reverting to 1950s practice, dimming or switching off street-lamps in the early hours of the morning, usually from midnight onwards. At the time of writing (mid-2011), more than half of the 433 local councils in the UK are

http://dx.doi.org/10.1007/978-1-4614-3822-9_5

http://www.starrynightlights.com


Fig. 3.5 ( a ) FCO road luminaire with careful optics, designed for residential streets (Courtesy D.W. Windsor Ltd). ( b ) FCO in pro fi le; this type is increasingly seen on Britain’s main roads (Courtesy Urbis Lighting Ltd). ( c ) FCO with multiple lamps; often used on roundabouts and busy road junctions (Courtesy Siemens Ltd)

61Road Lights

practicing some kind of exterior light control (according to a BBC report in mid-2011). Money has been saved: Dorset County Council, for example, claims that part-night switch-offs are saving about £150,000 (about $245,000) a year. The population of Dorset is about 750,000 people. In the USA, Santa Rosa, California set the trend by removing 6,000 of the city’s 15,000 streetlights, and switching off 3,000 others from midnight until 5:30 a.m., saving a reported: $400,000 a year. Among many communities following this example are Montgomery, Pennsylvania, which turned off one-third of its lights; Dennis, Massachusetts, dousing 832 lights (savings of $50,000 a year); and South Portland, Maine (112 lights, savings of $20,000 a year).

In 2008, members of the Campaign for Dark Skies presented an award to the UK Highways Agency (HA) at their Victoria headquarters in London (Fig. 3.6 ). The HA lights Britain’s main roads. In the 1960s and 1970s the majority of lit roads were lined with poorly controlled low-pressure sodium (orange) lighting, with a large percentage of emissions going skywards. Now, lit motorways and trunk roads have impressive numbers of replacement full cut-off (FCO) units, which, with their fl at glass parallel to the road surface, direct light only downwards. In 2007 the HA revised two of its standards (TD34 and TA49) that determine the criteria for whether roads should be lit, and the type of lighting employed. According to the HA, recent statistics had shown a 10% reduction in accidents on lit roads compared to the 1970s, when it was 30%. While 10% still seems signi fi cant, they stated, there are other ways the same resources can be used to reduce accidents, which negates the need for lighting in some cases. In future, they say, we will see some new UK roads without lighting and some refurbishment where lighting is not replaced. Furthermore,

Fig. 3.6 Bob Mizon and David Paul present the Campaign for Dark Skies’ Award of Appreciation to Ginny Clarke, Chief Highways Engineer of the UK Highways Agency


all HA lighting now conforms to the “G6 standard,” which stipulates no upward emissions. This category was previously mandatory only in national parks. Scotland and Northern Ireland have also adopted the Highways Agency’s new standards, so they apply throughout the UK. So, as far as direction of light is concerned, road lighting in the UK is improving. However, beside those well-lit roads, poorly aimed sports ‘ fl oods’ and glaring private lights are still sadly all too common.

Degradation of the Environment

The various aspects of this are discussed below. Some general facts are only too obvious: to produce the electricity for misdirected and super fl uous light, more fos-sil fuels are burned in power stations than would otherwise be burned, extra green-house gases are produced, and more atmospheric pollution created.

Skyglow

This has already been de fi ned and discussed in Chap. 2 .

Glare

Over-bright and poorly directed lights can dazzle or distract, paradoxically hiding whatever (or whoever) is in their vicinity. Many sports fl oodlights (Fig. 3.7 ), and the cheap and vastly overstated 500 W “security” light, so common in domestic use,

Fig. 3.7 Glaring sports fl oodlights at a leisure centre. The centre received a CfDS Good Lighting Award when the lights were re-angled (Photo: Gerard Gilligan)

http://dx.doi.org/10.1007/978-1-4614-3822-9_2

63Degradation of the Environment

fall into this category. Floodlights illuminating commercial premises and sporting venues are often a source of glare to passing road traf fi c, but the effect is most commonly experienced from incorrectly mounted and dazzling domestic ‘security’ lamps, as described below.

Glare is caused by light that is spilled in any direction from luminaires that causes discomfort, distraction or inability to properly see what the light is supposed to be illuminating. Lights that conceal rather than reveal defeat the whole purpose of lighting and can truly be called “anti-lights” (Fig. 3.8 ).

Glare is the most safety-related aspect of light pollution. This effect need not be uncomfortably bright to affect the observer adversely. A simple experiment to assess the impact of glare can be carried out from a moving car traveling along a lit road at night, keeping one’s eyes on the road but also being mindful of the effect of the brightness of the road lights. Lower the car’s sun visor, restricting upward vision, so that the light sources (bulbs) cannot be seen directly, and try to gauge any difference in comfort. If you feel more comfortable, the lights are emitting an unnecessary and potentially distracting amount of glare. According to the recog-nized American authority on standards of illumination, the Illuminating Engineering Society of North America (IESNA, often referred to as the IES), glare may be cat-egorized as follows:

B linding Glare: a glare so intense that, for an appreciable time after the stimulus has been removed, no object can be seen or easily distinguished.

Fig. 3.8 Poorly angled fl oodlights dazzle drivers on this urban road


D isability Glare (Veiling Luminance): glare causing reduced visual perfor-mance. Drivers in cities are confronted with ever-changing and con fl icting light sources, many of them bright enough to cause disability glare: pupils constrict, trying to adapt to the brightest sources, and ability to see into shadowed areas is diminished. Poor and impatient driving may be the result. Disability glare is a typical result of an outward-facing 500 W security lamp being triggered by your presence as you approach the owner’s premises – what a welcome!

D iscomfort Glare: glare producing discomfort or annoyance without necessarily interfering with visual performance. The IESNA con fi rms that discomfort glare may cause fatigue, with safety implications for drivers, machine operators and the like.

Modern full cut-off luminaires (FCOs), which have a fl at glass sheet, or a slightly convex bowl, beneath a light source housed well up within the casing, emit light only below the horizontal (Fig. 3.9 ). This assumes, of course, that they have

Fig. 3.9 A well enclosed fl at-glass light at a holiday park in France


been correctly installed with the glass parallel to the ground below. FCOs are hardly seen from a distance, and illuminate the road while reducing, if not completely eliminating, glare into the eyes of approaching road users. Many new luminaires have a very shallow curving glass beneath the casing, transmitting light sideways and downwards, to avoid the effect of constant ‘ fl ashing’ into drivers’ eyes caused by the sudden staccato appearance of the light sources as the vehicle approaches them.

Light Intrusion (Formerly ‘Light Trespass’)

The unwelcome spilling of light to cause annoyance to people in neighboring prem-ises (Fig. 3.10 ) has been recognized as an actionable nuisance in law in the UK for some years now. Since April 2005, intrusive nuisance lighting has been an offence under the criminal law. The term “light trespass” originated in the United States, where local lighting ordinances are in force in some towns and counties (see Chap. 9 ). Other sources of information on US light trespass laws may be found on www.illinoislighting.org, and on www.ehow.com/list_6768966_government-laws-light- trespassing.html. The term has fallen out of favor in the UK, because ‘trespass’ in its legal sense implies intention. It is almost never the intention of the offender deliber-ately to cause annoyance – ignorance is nearly always the cause of the problem.

Fig. 3.10 Light intrusion: light spill from a car park in a rural area illuminates a room in a nearby house (Photo: Richard Murrin)

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Before 2005, common-law private nuisance actions had already been success-fully brought against intrusive lights in several UK cases. Interestingly, none of the complainants in these cases were astronomers. However, such an action required the complainant to sue the party responsible, usually at considerable expense in time and money.

In 2005, exterior lighting fi nally became subject to the criminal law of statutory nuisance, and now the State may prosecute the owner of an offending light. The change in the law was introduced by Section 102 of the Clean Neighbourhoods and Environment (CNE) Act (2005). A complainant can take the matter up with the Environmental Protection Unit of their local council, who in turn may initiate pro-ceedings in the Magistrate’s Court. The issue of whether street lights are covered by this new law is a vexing one, which remains to be tested.

A letter was published in a British city newspaper in 2006, summing up why action is needed on poorly aimed street lights shining through windows. The author of the letter stated that he had “lost the hours of darkness so necessary for a good night’s sleep.” His nights were now lit up like the day, and shielding did little to alleviate the problem. Residents of the small village of Broadwindsor in Dorset complained to their local authority in 2009 when new lights “lit up the village like a football stadium.” New lighting columns are often taller than those they replace, increasing the likelihood of light intrusion into bedrooms (Fig. 3.11 ).

Transport-related premises, for example docks, railway stations and bus depots, were exempted from the CNE Act (for no good reason, in the opinion of the

Fig. 3.11 An intrusive streetlight shines through the windows of houses (Photo: CfDS)


Campaign for Dark Skies and other like-minded organizations). It has become apparent that, in spite of the legislation, many UK local authorities fail to support complainants whose lives have been affected by stray light. Unacceptable noise, smoke and vicious dogs may well lead to a visit from a public health of fi cial empowered to act against these nuisances, but intrusive light is more likely to be tolerated by some authorities. The use of standardized light-level measuring devices (luxmeters) would go a long way towards solving this problem.

Of course, the solution to intrusive lighting is, more often than not, simply shielding or re-angling the offending light, or reducing its power. There is usually no need to permanently switch off necessary lights. The answer is well controlled and well directed lighting, of sensible wattages.

The CNE Act does not speci fi cally protect the night sky, but any action on poorly directed lamps is good news for astronomers. Campaigners continue to work towards ‘star-quality’ lighting, and for the starry night sky to have as much protec-tion as any other part of the environment.

Law lecturer Francis McManus of Napier University, Edinburgh, discussed intrusive light at a light-pollution seminar organized by the UK National Society for Clean Air and Environmental Protection (NSCA) in November 1999. He stated that “there is no doctrinal reason why light should not be considered a pollutant and a nuisance in law.” In a seminal article, “Light Pollution: a Review of the Law,” in the Journal of Planning and Environment Law (January 1998), lawyer Penny Jewkes wrote: “Environmental protection is the sum of small concerns; this is the essence of sustainable development, which requires that decisions throughout soci-ety are taken with proper regard to their environmental impact. The planning sys-tem goes some way to achieving this, but it was never designed to bear the full responsibility for the control of light pollution.”

Impact on Wildlife

In November 2008, Verlyn Klinkenborg (in National Geographic ) described how the human race had “invaded the night.” Is it really ours to occupy? Vast numbers of the world’s species are nocturnal. The invasion of their world by arti fi cial light-ing has consequences that we are only just beginning to investigate and quantify.

Animals disturbed, and killed, as a result of stray light have no curtains to pull. There are many reports of its deleterious effects on large numbers of different spe-cies: insects, birds, fi sh, reptiles and mammals. For example, Professor Gerhard Eisenbeis, of the University of Mainz in Germany, has led considerable research into the impact of light spill upon insect populations, and speaks of a “vacuum-cleaner” effect, sucking insects to their doom out of habitat areas. In a recent article (2011) in the magazine Natur und Landschaft , entitled (in translation) “Attraction of nocturnal insects to street lights,” Professor Eisenbeis stated that “Arti fi cial lighting in the environment has had a deep impact on the natural world, especially on nocturnal animals. This takes place against a background of dramatically falling


biodiversity in nearly all the Earth’s habitats. At the same time, arti fi cial lighting is only one factor among many environmental pressures. Urban sprawl in the coun-tryside, the conversion of natural habitats to intensive human exploitation and the release of arti fi cial substances have contributed to a situation where biologists speak of the sixth wave of extinctions in the living environment.”

In their report entitled Review of the Impact of Arti fi cial Light on Invertebrates ( 2011 ) , Charlotte Bruce-White and Matt Shardlow of Buglife, a UK-based organi-zation devoted to the conservation of all invertebrates, concluded:

Invertebrates make up the majority of biodiversity and they are vital to ecosys-tems….Arti fi cial light in the wrong place at the wrong time adversely affects the life cycles and survival of invertebrates. This could have knock-on effects at a population level, contributing to declines and extinctions of species (Fig. 3.12 ).

Fig. 3.12 A species in decline: the house sparrow, whose young are insectivorous (Photo: Steve Smith)


Arti fi cial light has the potential to signi fi cantly disrupt ecosystems and it has long been of concern to conservationists. It is widely observed that some inver-tebrates, such as moths, are attracted to arti fi cial lights at night. Arti fi cial lighting can signi fi cantly disrupt the natural light/dark patterns. Many invertebrates depend on the natural rhythms of day-night and seasonal and lunar changes to light levels. As a result arti fi cial lighting has several negative impacts on a wide range of invertebrates, including disrupting their feeding, breeding and move-ment, which may reduce and fragment populations. In addition, the polarisation of light by shiny surfaces is a signi fi cant problem as it attracts aquatic insects, particularly egg-laying females, away from water, and re fl ected light has the potential to attract pollinators and impact on their populations, predators and pollination rates.

Because invertebrates are so fundamentally important to healthy ecosystems, and because declines and threats mean that many species are already listed as national priority species for conservation under the UK Biodiversity Action Plan (UKBAP), it is imperative that avoidable threats to their well-being are avoided.

Action to reduce arti fi cial light impacts is necessary and justi fi ed now. Although further research is required to fully understand the impacts of arti fi cial light on invertebrates and the environment as a whole, the precautionary principle applies and enough is known to take action now. This report makes several rec-ommendations that would reduce and mitigate the negative effects that arti fi cial light has on invertebrates. Local authorities and Government departments must take a lead on reducing the impact of arti fi cial light. The environmental impact of light for new developments must be more prevalent in the planning process and more routinely part of the Environmental Impact Assessment process. Public bodies have a ‘biodiversity duty’ under the Natural Environment and Rural Communities Act (2006) and Nature Conservation (Scotland) Act (2004), and must consider the impact that lighting, polarisation and re fl ection will have on biodiversity. Light pollution levels should be generally reduced everywhere. However, it is particularly important that areas that currently have low lighting levels and areas that are important for wildlife should be identi fi ed and progress to become Dark Sky Preserves. Established lighting schemes should also be reconsidered to reduce their impact on the environment. In addition, the issue of arti fi cial light and its environmental impacts on invertebrates and other wildlife should be given a greater public pro fi le.

Insect numbers, we are told, are declining. In the UK in the summer of 2004, nearly 40,000 drivers volunteered to keep a tally of insects found splattered on their vehicles’ number-plates. The Royal Society for the Protection of Birds’ “Big Bug Count” project (since repeated) distributed cardboard counting-grids (“splatome-ters”). Drivers recorded an average of only one squashed insect for every 5 miles driven, a result considered indicative of a marked fall in insect numbers. Decades ago, said commentators, cars would have swept up far more. Nobody suggests that


stray light is the primary cause of falling insect numbers, but it cannot be denied that more research is needed to assess its contribution.

A fi eld study (see Bibliography ) carried out in 2010 in the Austrian Tirol region by Dr. Peter Huemer, Hannes Kühtreiber and Dr. Gerhard Tarmann compared num-bers of fl ying insects (predominantly moths, though many other species, such as lacewings, were recorded) attracted to different kinds of modern light sources. Their conclusion was that metal halide “daylight” lamps (5,600 K), now becoming quite common as street lights and area fl oodlights, attract about twice as many insects as their high-pressure sodium (2,000 K) predecessors; while “warm white” LEDs (3,000 K) attract fewer – about one-sixth as many as “daylight” metal halide lamps.

These researchers make the point yet again that insects are the class with the largest number of species on Earth and represent the majority of the planet’s biodi-versity. They are very important pollinators of plants and an irreplaceable link in the food chain. In 2006, Colin Henshaw and Graham Cliff (see Bibliography ) warned: “Insects are the primary food source for many predators (such as bats, birds, lizards and frogs), and their decline has a serious knock-on effect for other creatures.”

Many species of insects are active at night and are attracted by light. Whenever they are disturbed by an arti fi cial source of light during feeding and reproduction, they start circling around the luminaire, often for a very long time. If this occurs for several successive nights, they will fail to carry out their biological missions. When a new source of light appears, it can devastate a population of moths in one season, and they may vanish from the immediate vicinity in a few years.

British Astronomical Association member Robin Scagell has carried out a nationwide survey of Britain’s glow-worm population. These intriguing insects (they are not worms) glow like tiny green LEDs in the grass on summer nights, try-ing to attract a mate. They need only a regular food supply and a dark environment to thrive (Fig. 3.13 ). Their food (mostly tiny snails) is still available, but their num-bers are in continuous decline. Is the encroachment of arti fi cially bright skies over their habitats a cause of falling glow-worm numbers over the last 40 years? Similar questions are being asked in other parts of the world about bioluminescent species in decline, for example fi re fl ies in the United States (see www.illinoislighting.org/ fi re fl ies.html ).

Foraging bats hunt for nocturnal insects, their main source of food. Many bats roost in buildings, and nearby illumination, whether direct or indirect, will affect the times at which they emerge, with consequent lessening of the opportunities they have to fi nd food. Researchers have reported that the presence of exterior lighting changes may shorten their foraging paths. Dr. Jenny Jones, of the Hertfordshire and Middlesex Bat Group, wrote in a paper entitled “Impact of Lighting on Bats” (2000):

“ Studies have shown that, although noctules, Leisler’s, serotine and pipistrelle bats swarm around white mercury street lights feeding on the insects, this behav-iour is not true for all bat species. The slower- fl ying broad-winged species such as Plecotus, Myotis and Rhinolophus avoid street lights. In an important bat site in

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Suffolk, numbers of Natterer’s, whiskered, Daubenton’s and brown long-eared bats fell following the installation of street lamps nearby.

Arti fi cial lighting can increase the chances of predation. It is believed that Plecotus and Myotis species shun bright light as a predator avoidance strategy. Many avian predators will hunt bats, which may be one reason why bats avoid fl ying in the day. Observations have been made of kestrels (diurnal raptors) hunting at night under the arti fi cial lights along motorways.

Floodlighting will deter bats from using their usual foraging areas. Lighting can be particularly harmful if used along river corridors, near woodland edges and near hedgerows used by bats. Studies have shown that continuous lighting along roads creates barriers which bats cannot cross. For example, Daubenton’s bats move their fl ight paths to avoid street lamps.” Baby sea turtles in many areas of the world emerge from the eggs that their

mothers have laid beneath the sand of carefully selected beaches. The hatchlings head for the light cues of the Moon and stars (the brightest horizon). Since water re fl ects light (even starlight), the ocean is usually the brightest thing that the babies see. If the local nightclub, road or parking lot lights along the beach road outshine the Moon, they will turn the wrong way and scrabble inexorably to their doom inland. Sea-turtle rescue volunteers in Fort Lauderdale, Florida, criticized city leaders in the summer of 2011 for continued over-lighting and lack of proper shielding of lights in the vicinity of local beaches. Every night during the hatching period, they

Fig. 3.13 A glow-worm signals its position at dusk beneath a fi ne display of noctilucent clouds (Photo: Dave Tyler)


had to rescue scores of baby turtles “scurrying not toward the ocean surf but toward city-owned street lights.” They pointed out that turtle populations are dwindling, and that the “nightly massacre” of disoriented hatchlings beneath the wheels of vehicles on coastal roads was undoubtedly a contributory factor (see seaturtleop.org ). A detailed report on the problems turtles face with lighting can be found on www.starrynightlights.com/light_pollution/Sea_Turtles/light_pollution_and_sea_turtles.html . Humbler sea creatures, from fi sh to the teeming, minuscule denizens of coral reefs, also have to contend with arti fi cial lights from shore installations, offshore platforms and fi shing vessels (see Recommended Reading in the appendix of this book, Rich and Longcore, Ecological Consequences of Arti fi cial Night Lighting ).

Birds are affected by stray light intruding into the nocturnal world (Fig. 3.14 ), confusing natural behavior, breeding cycles and fl ight patterns. In New Scientist , March 1995, Fred Pearce considered the plight of exhausted songbirds, singing all night long as ‘security’ lights constantly triggered their dawn response, the rhythms of millions of years overturned by thoughtless lighting. The supposedly decorative fl oodlighting of trees, often by local authorities, and by arboretums who claim to be guardians of the environment, not only robs local bird populations of a secure roost but also plays havoc with the day-night responses of the literally thousands of different organisms, both complex and humble, to which trees are a home (Fig. 3.15 ).

Fig. 3.14 Birds’ circadian rhythms are seriously disturbed by night-time fl oodlighting of their habitats (Photo: Chris Baddiley)

http://seaturtleop.org

http://seaturtleop.org

http://www.starrynightlights.com/light_pollution/Sea_Turtles/light_pollution_and_sea_turtles.html

http://www.starrynightlights.com/light_pollution/Sea_Turtles/light_pollution_and_sea_turtles.html

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I saw, as a child in East London in the 1950s, fl ocks of house sparrows noisily foraging in the garden. My mother would tell me not to feed them, as their numbers were so great she regarded them as a plague. Returning to that area nowadays, there is scarcely a sparrow to be seen, and other, once numerous species such as starlings are noticeably absent. What has changed in that environment? The parks, trees and gardens are still there. The cat population is probably about the same. The two markedly different things I notice are the vast increase in road traf fi c, and the pro-liferation of lighting at night. The British Trust for Ornithology (BTO) reported in 2007, at www.bto.org/birdtrends2008/wcrhousp.shtml , a 60% decline in UK house sparrow numbers in urban areas since the mid-1970s, as opposed to a 47% decline in rural areas. BTO concludes that “the European status of this species is no longer considered secure.” Although adult sparrows eat grains, their young are fed on insects. Any fall in the insect population (a decline to which lighting contributes) impacts upon them, and upon all other insectivorous creatures. Thrushes, buntings, starlings and many other species are on the BTO “red list” of threatened populations.

Lights vastly increase the mortality rates of migrating wild birds. In the United States and Canada there is growing concern over the increasing number of migrant birds dying nightly as a result of striking illuminated buildings and lit structures such as radio and TV masts, or fl ying around them until they fall exhausted. The Audubon Magazine of April 2000 carried a report from the American Bird Conservancy, stating that at least four million birds die every year in the United States alone (and the fi gure may be much higher) in encounters with illuminated

Fig. 3.15 A fl oodlit tree (Photo: Andreas Haenel)

http://www.bto.org/birdtrends2008/wcrhousp.shtml


structures. Many songbird species have evolved to migrate during the hours of darkness, when predators retire and winds subside. Most of the dead and wounded birds that fall to city streets at night are “cleared up” by urban scavengers such as rats, foxes, cats, raccoons, crows, and seagulls.

In Toronto, in 1 year, volunteers from the Fatal Light Awareness Program (FLAP) gathered more than 3,000 dead and wounded birds of 138 different species. FLAP works to educate of fi ce building managers about the problem of birds collid-ing with their buildings, simply by switching off lights at night during the migration season. Energy savings are the bonus! In 2006, the Royal Ontario Museum mounted a display of approximately 2,000 birds from 89 species killed in collisions with human-built structures during the 2005 season. The dead birds, collected by FLAP, included hummingbirds, woodpeckers, warblers, thrushes, sparrows, and kinglets. In January 2006, Toronto was the fi rst city in the world to implement a migratory bird protection policy – Lights Out Toronto. This legislation seeks to protect birds by controlling light from buildings, increasing public education, and promoting bird rescue. Chicago’s Hancock Center cut its ornamental night-time lighting in 2003 after administrators learned that nearly 1,500 migrating birds had nightly met abrupt deaths in encounters with its brightly lit tower during one season, mistaking its illumination for stars or the moon ( www.nnhs.org/info ). Dozens of other build-ings followed the example. Needless to say, birdwatchers would like all buildings to extinguish interior lights and non-essential outdoor lights (especially all fl oodlighting) during migration time, and to shield essential lights.

There are frequent reports of large numbers of sea birds crashing into fi shing vessels using powerful fl oodlights (see, for example, www.jstor.org/pss/3782548 , Attraction of Hawaiian Sea Birds to Lights ). In 2009, the British Antarctic Survey earned the Campaign for Dark Skies’ Good Lighting Award for its shielded-lighting policy on ships and shore stations, to protect local birdlife.

More information on the effects of arti fi cial lights on birds can be found at:

www.abcbirds.org www. fl ap.org www.lightpollution.org.uk

The examples cited in this chapter touch on just a few of the problems that countless millions of our fellow-creatures on this planet have because we do not always aim lights properly or use sensible wattages. On its website www. illinoislighting.org , the Illinois Coalition for Responsible Outdoor Lighting (ICROL) sums up the urgency of the situation, reminding us that far too little research has been done on nocturnal habitats and lighting, and time is short. ICROL concludes: “We must not make the mistake of imagining that the “natural world” is off in a preserve somewhere far away, and that our “manmade space” around our towns and cities is somehow exempt from the laws of nature. “Natural” systems are everywhere; not just including the fi re fl ies (formerly) in our yards, but within our very selves. And the effects from the lights in our towns not only permeate their landscapes, but also carry far, far beyond the town boundaries. Unfortunately, we are not likely to see a massive program instituted to study nocturnal biology

http://www.nnhs.org/info

http://www.jstor.org/pss/3782548

http://www.abcbirds.org

http://www.flap.org

http://www.lightpollution.org.uk

http://www.illinoislighting.org

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(scotobiology), and identify how manmade light is affecting thousands of different species of living things. So, we are faced with two choices: Pretend that our lighting creates no ecologically damaging effects, or own up that our lighting must be caus-ing ecological effects, and then obey the precautionary principle which says that since some of those effects are likely to cause serious harm, we should act pro-actively now – even before the last species has undergone rigorous study.”

Nobody has said it better than Catherine Rich and Travis Longcore, authors of the de fi nitive book Ecological Consequences of Arti fi cial Night Lighting : “Nature needs the night.”


Arti fi cial Lighting, Quality of Life

and Health

Chapter 4

Lighting and Human Health

Wasted light – harmful or merely an irritant? Surely it doesn’t kill people… Unfortunately, it does, as some victims of accidents caused by glaring lights are

no longer here to testify. The quality of life of people affected by unwanted light from neighboring premises is often greatly diminished, and there is an increasing body of evidence that intrusive light, especially into rooms where people are asleep or are trying to sleep, may be harmful in the long term.

One correspondent (a non-astronomer) who wrote to the British Astronomical Association (BAA) described how he had suffered from lack of sleep for a pro-longed period because of the domestic fl oodlights of two neighbors, which were on at most hours of the night and shone brightly through his bedroom window. His request for their modi fi cation having been politely but fi rmly turned down, he was forced to sleep in another room, but was still troubled by the light. The situation was aggravated by the fact that his job required him to get up at a very early hour. In the end, having changed jobs as a result of interrupted sleep and fearful for his health, he solved the problem at great personal expense by moving to another house. The BAA’s postbag shows that he is not unique in his predicament, and the organization has even received letters from people contemplating suicide because of intrusive lights (Fig. 4.1 ). This author was invited to be an expert witness in a light-intrusion case in Wales, and well remembers the mental anguish of an elderly couple whose premises were massively fl oodlit by the light towers of a nearby sports facility: behind a thick blanket pinned inside their bedroom window, with the light off in the room, I could still read the small print on a credit card. The glare

78 4 Artificial Lighting, Quality of Life and Health

from the lights as I entered their garden was blinding (the elderly gentleman had earlier fallen over and injured himself because of this). Thankfully, they won their case and received costs and damages, and the offending lights were shielded and re-angled.

Ill-directed and over-bright lighting can cause as much inconvenience and stress as other pollutants, and complainants, driven to seek solutions in the courts, ought not to be treated as “hypersensitive,” or be advised by a thoughtless judge – and it was really said – to “ fi t thicker curtains.” It would probably never have occurred to the judge to tell a woman complaining of foul smells from next door to put a clothespin on her nose, or a man troubled by noise from a neighbor’s all-night “rave” parties to use earplugs. It is a tenet of the laws of nuisance that the polluter should both seek the remedy and pay the cost. Nobody told by a judge or a local authority to screen out intrusive lighting should accept such an instruction; it is up to the owner of the light to solve the problem.

Here are two examples of fatalities caused by poorly aimed lighting:

In May 2002, in Oxfordshire, England, a man was hit by a car and killed after a security light temporarily blinded the driver. A bright fl oodlight, shining from a bar, had obscured the driver’s vision. The police reconstructed the accident. A policeman noted, “When I was driving towards the scene, the of fi cer standing

Fig. 4.1 Intrusive light cut down by FCO lights in a residential area (Photo: Urbis)

79Lighting and Human Health

where [the deceased] would have been was barely visible because of the security light” (source: the Oxford Mail ).

In July 2002, in Australia, two aircraft collided as they approached the runway at Melbourne’s Moorabbin airport. A commercial pilot with 200 hours’ fl ying time died after her plane hit the runway in fl ames. Poor visibility because of the impact of surrounding lights was found to be a factor in the crash. An optics consultant said that bright lights around the perimeter of the airport wash out the small amount of light emitted from small aircraft’s navigation lights: “You have this enormous collection of lights shining uselessly into the sky, and it is becom-ing increasingly dif fi cult to see the airport and surrounding planes,” he said (source: the Melbourne Age ).

Having evolved, like nearly every other species on Earth, to follow a light-dark cycle, we (not surprisingly) fi nd it dif fi cult to cope with a life of international travel across time zones, working night shifts and sleeping in the day, staying up beyond dusk, and living by the social clock rather than the solar one. Dr. Steven Lockley writes:

Access and exposure to arti fi cial light at night has become pervasive in all indus-trialised nations and is becoming increasingly so in the developing world. This light affects all organisms exposed to it, not just humans, and the consequences of such a dramatic alteration in one of the most powerful environmental signals is not yet known. Given its relatively recent introduction, we are only at the beginning of understanding the impact of arti fi cial light on human health. Research over the past 80 years, however, has shown that light exerts very pow-erful effects on human physiology, endocrinology and behaviour, and, having evolved in a distinct light-dark cycle, it is possible that unnatural exposure to arti fi cial light at night is hazardous to human health. The hormone melatonin (N-acetyl-5-methoxytryptamine) is secreted during the

hours of darkness into the blood by the pineal gland in the brain – it is the biochemi-cal signal of night. Melatonin levels and its 24-h rhythm are governed by the 24-h circadian clock, which also controls the timing of many other rhythmic outcomes (e.g., sleep-wake cycle, temperature rhythms, patterns of alertness, moods and performance). The circadian clock has an intrinsic rhythm close to, but not exactly, 24 h and needs to be reset each day to synchronize with the outside world. The 24-h light-dark cycle is the strongest environmental time cue to entrain the clock, which in turn entrains its rhythmic outputs, including the melatonin rhythm.

Many biological effects of melatonin are produced through the activation of melatonin receptors. It is a powerful antioxidant, scavenging free radicals and thereby helping to prevent cancer cell damage and proliferation. It has been linked with the ef fi ciency of our immune systems, to the regulation of aging, and has a particular role in the protection of nuclear and mitochondrial DNA. Light exposure at night, which could not be achieved in any great amount before the advent of electric lighting, suppresses melatonin production and resets the biological clock, as the clock tries to reset to this new ‘day’ signal. Exposure to even small amounts of light during the night, and certainly the light generated from indoor lamps, immediately and considerably inhibits melatonin production.


Dr. Lockley adds: “Studies are underway to measure the actual light levels that people are exposed to while indoors and, in urban environments, these light levels are likely to be signi fi cant, and even higher when individuals live closer to intrusive street lighting. Unnecessary horizontal and vertical street lighting permeates living spaces, particularly bedrooms. This light intrusion, even if dim, is likely to have measurable effects on sleep disruption and melatonin suppression. Even if these effects are relatively small from night to night, continuous chronic circadian, sleep and hormonal disruption may have longer-term health risks.”

Light is the main agent in synchronizing circadian rhythms in nature, and human beings, still conditioned by millions of years of evolution to a regular cycle of dark and light, can certainly suffer from an excess of either. Light therapy has been used to good effect in cases of seasonal affective disorder (SAD), a depressive reaction to the dull days of winter; but, as Dr. David Avery, professor of psychiatry and behavioral sciences at the University of Washington (WA) School of Medicine pointed out in a de fi nitive, independent paper on the subject of light as therapy in 1999 (see Bibliography ), we need a balance between light and darkness. The paper recommends a fi ve-point light exposure regime: “Increase daytime light exposure; decrease evening and night-time light exposure; create a regular light-dark cycle; fi nd optimal durations of darkness and sleep; avoid sleep deprivation (and) exces-sive sleep.” Dr. Avery continues: “For many people, if these principles are not fol-lowed, the consequences are minor…however, for some individuals, perhaps because of increased vulnerability, the consequences may be substantial, as occurs in patients with SAD.” Decreasing our exposure to light in the evening is therefore as important as receiving the right intensity of light during the day: “The bedroom should be as dark as possible without compromising safety… if security lights or street lights illuminate the bedroom, the curtains need to be closed” – and cam-paigners against poor lighting would go further and say that those offending lights need adapting! Dark nights and light days, with regular 24-h timing for both, are the key to good circadian rhythm synchronization and good sleep (Fig. 4.2 ), and vital for appropriate temporal organization of our physiology and metabolism.

A recent BBC report (2010) con fi rmed that the vast majority of today’s children “have never experienced total darkness,” being surrounded all night, outside and indoors, with arti fi cial lights. The report was quoting research sponsored by a power company, Powergen, which found that a startling 98% of British children do not sleep in darkness. In one in three households, a night-light remains on actually in the children’s bedrooms, at an estimated cost of £468 million a year. Powergen’s energy ef fi ciency manager, Mike Newell, reportedly said: “Coupled with the effects of street lighting, many of our children will grow up without ever knowing what true darkness really is.” (Fig. 4.3 )

More and more research is being reported linking exposure to arti fi cial light to human health problems. As a result, the American Medical Association (AMA) voted unanimously on June 16, 2009, to support efforts to control light pollution, on the basis that, in their words:

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Many species (including humans) need darkness to survive and thrive; • Glare from bad lighting is a public-health hazard – especially the older you • become. Glare-light scattering in the eye causes loss of contrast and leads to unsafe driving conditions, much like the glare on a dirty windshield from low-angle sunlight or the high beams from an oncoming car;

Fig. 4.2 Light intrusion into a fi rst- fl oor bedroom

Fig. 4.3 Night in the city: darkness is a thing of the past. Gloucester at night (Photo: Chris Baddiley)


Wasted light represents unnecessary energy and CO • 2 production.

The AMA passed a resolution calling for:

All future outdoor lighting to be of energy-ef fi cient designs to reduce waste of • energy and protect the environment; Light-pollution reduction efforts and glare-reduction efforts at both national and • state levels; and All future streetlights to be of a fully shielded or similar non-glare design to • improve the safety of roadways for all, but especially vision-impaired and older drivers.

The British Independent newspaper reported in 2006 on research by Dr. David Blask and colleagues (U.S. National Cancer Institute and National Institute of Environmental Health Sciences), investigating why the incidence of breast cancer in rich countries is about fi ve times greater than in developing nations. The study involved scientists grafting human breast cancer tumors onto rats, and then infusing them with blood taken from women during the day, in the early hours of the morn-ing, and after being exposed to light at night. The “dark-night” blood slowed the growth of the tumors by a reported 80%; blood taken after exposure to the light had the opposite effect.

Reports emerged in 2008 of a study in Israel by chronobiologist Professor Avraham Haim, doctoral student Itai Kloog and Professor Boris Portnov of the University of Haifa, concluding that exposure to light at night may be a signi fi cant cause of breast cancer. Breast cancer is the second most common type of cancer in the United States, and the most common in the UK and in Israel. The Israeli researchers stated that women in street-lit towns are “37 percent more likely to suf-fer from the disease than others in dark areas, and (the risk is) a further 27 percent higher in areas with the highest amount of outdoor lighting” ( Chronobiology International 2008 and 2011 , see Bibliography ). The work was described to dele-gates at the Eighth European Dark-Sky Symposium in Vienna (2008) by Itai Kloog, who related how NASA satellite images had been used to compare light emitted from various towns and villages throughout Israel with breast cancer statistics from the Israeli National Cancer Registry. The researchers also investigated as controls many other factors (socioeconomic, environmental, and genetic) of the women’s lives. “We are not saying that light at night is the only, or even a major factor in breast cancer,” said Kloog. “However, the strong correlation is there. It must be taken into account.”

Studies elsewhere, by other researchers, of night-shift workers (for example, nurses and fl ight attendants) have found rates of breast cancer considerably higher than normal. Interestingly, rates of breast cancer in totally blind women have been found to be less than average.

Professor Charles Czeisler of the Harvard Medical School commented in 2006: “If light were a drug, the government would not approve it.” Professor George Brainard, director of the Light Research Program at Philadelphia’s Jefferson Medical College, said, also in 2006: “Humans evolved on a planet without electric

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light over thousands and thousands of generations. The body is designed to be alert and awake during daytime hours and to sleep at night. Now we have a 24/7 society that isn’t in harmony with our biological design.”

So the doctors and academics, echoing the dark-sky campaigners, stress that we tamper with our age-old day/night responses at our peril.

Can excessive and misdirected lighting affect even the air we breathe? Of course, if it leads to increased burning of fossil fuels and dirtier air, but there is more. Does light at night more directly increase urban ‘smog’?

At a meeting of the American Geophysical Union in April 2011, Harald Stark, of the NOAA’s Earth System Research Laboratory, reported on airborne experi-ments to measure the intensity of city lights over Los Angeles (Fig. 4.4 ). One unexpected conclusion of this study was that the urban glow was affecting night-time atmospheric chemistry. At night, the nitrate radical NO

3 , a compound

destroyed by sunlight, re-forms in the darkened sky, neutralizing some of the nitro-gen oxides (NO

x ) that pollute the daytime air, causing unhealthy levels of ozone

(O 3 ). Bob Parks, executive director of the International Dark-Sky Association, said

“Many cities are close to their limits of allowable ozone levels, so this news is expected to have big implications for outdoor lighting practices and should be of special interest to the Environmental Protection Agency. Two years ago the EPA

Fig. 4.4 Los Angeles, night-time view (Photo: CfDS)


was petitioned to assess light pollution’s role in atmospheric discoloration of the night sky under the Clean Air Act, but so far the agency’s of fi cials have made no formal response. But this new scienti fi c result will certainly get their attention.”

Evidence piles up that the indiscriminate use of light is not as harmless as was once thought. When we fi nally get outdoor lighting right, it will be good not only for our view of the stars above, but also for the very fi bers of our being.


Arti fi cial Lighting and Crime

Chapter 5

Owners of lights left on all night, aimed high and glaring into the surroundings, will often bristle when challenged about their quality and usefulness. Even if reassured that you do not actually want them to switch off their lights, they will continue to insist that “we need them on for safety and security.” Tabloid newspapers almost invariably print sensational headlines such as “PLUNGED INTO DARKNESS” and “SWITCH-OFFS – CRIME-WAVE FEARS” when local authorities announce the part-night turning off of selected street lights.

So, are lighting and crime levels related? At the time of writing (August 2011), several city centers in England were witnessing “copycat” night-time riots (Fig. 5.1 ), not apparently politically motivated, involving gangs of disaffected youths looting shops and sometimes setting fi re to them. These riots were taking place in brightly lit retail areas.

What was the role of the lighting here, both in the streets and left on in the shops? Of course, it allowed the forces of law and order to see what was going on and to take action. It helped CCTV cameras to record the scene. But it also helped the malefactors to organize their activities, spot the police, pillage the shops and make their escape. The shops’ interior lighting, left on when they closed, reveals high-value target objects and helps the trespassers steal them. It worked both ways.

Those who believe that bright lights deter criminals miss the important point that lighting is of use to anyone who needs to see. Often it is of such poor quality that it conceals (through glare) rather than reveals (Fig. 5.2 ). Ef fi cient lighting, a feeling of security, neighbors’ comfort and a view of the night sky are NOT incompatible.

Dark-skies groups acknowledge the need for certain lights at night and have never called for the switching off of any necessary, unobtrusive light. What they ask for is that lights should be no brighter than needed, and they should illuminate only

86 5 Artificial Lighting and Crime

Fig. 5.1 Rioters in an English city, summer 2011 (Photo: Alex Cater)

Fig. 5.2 Glare from a rural car park light that would conceal any wrong-doing occurring there (Photo: Richard Murrin)

87Crime Reduction

the area to be lit, for no longer than necessary. They should not be installed in the hope that they will deter criminals. Glaring, outward-facing “security” lamps offer little real security if they dazzle potential witnesses to any wrongdoing, and provide a wall of light behind which a burglar can work unseen.

Crime Reduction

If modern, well-directed lighting in streets and on buildings were de fi nitely seen to reduce crime, anti-light-pollution campaigners, who have been promoting the bene fi ts of well-designed lighting systems for years, would rejoice. However, evi-dence for such a relationship remains far from conclusive.

Correctly positioned and angled lighting, which makes potential and actual offenders more visible to any onlooker, seems a sensible idea, assuming that wit-nesses are in fact present. Equally sensible is the reduction of glare in the direction of potential witnesses, and the avoidance of creating deep shadows, which can provide hiding places for malefactors. If the design of “security” lighting took such aspects into account (which it largely does not), there might be a case to argue for lighting as a crime deterrent (Fig. 5.3 ).

Studies exist, usually funded or part-funded by the lighting industry, which suggest that brighter or more numerous lights, or the introduction of lighting, can

Fig. 5.3 More lights that prevent the observer from seeing (it’s an airport) (Photo: IDA)


deter crime. These studies are used by manufacturers and others to argue that lighting can reduce the crime rate. They remain a source of lively debate, and stat-isticians argue over their validity. Also, the reduction in crime rates in areas where lights have been switched off late at night, and the low crime rates typical in unlit areas, suggest that the opposite may be true. In Radical Statistics , issue 104 (2011), Dr. Paul Marchant, statistician at Leeds Metropolitan University, examines the effects on crime of new lighting schemes in London during the years 2003–2009. His paper, entitled “Have new street lighting schemes reduced crime in London?” is based on crime data published by the UK Home Of fi ce for the Metropolitan Police Crime and Disorder Reduction Partnership areas. Dr. Marchant concludes that there is “no good evidence for lighting bene fi t in reducing total crime.” Levels of crime can vary remarkably in a single area over time (perhaps due to fl uctuations in individual proli fi c offenders’ criminal activities), making claims of crime reduc-tion due to external factors such as lighting likely to be unreliable.

Can Lighting Actually Aid Criminals?

More intensely lit areas, especially city centers, tend to have higher crime and incivility rates. Is the lighting actually facilitating crime? According to the British Crime Survey, most crime, especially domestic break-ins, occurs in daylight: the likelihood of being seen will not always deter criminals. Paradoxically, over- powered lights, shining outwards, guarantee that night-time criminal activity is less likely to be seen (see above). The presence of lighting can help criminals sur-vey an area and sort out their tools, highlight potential targets, determine easy pick-ings, and note security lapses and escape routes.

Does Lighting Automatically Reduce Crime?

According to the UK government’s Home Security and Crime Reduction website, “harsh, glaring fl oodlights are not a deterrent to criminals.” To some, this seems counterintuitive. Surely, they ask, being seen is the last thing the villains want? There are other questions to ask, however. Do the villains need to see what they are doing? Can they be seen through the glare? Are witnesses likely to intervene any-way? The Association of British Insurers does not recommend outdoor lighting as a crime deterrent. Indeed, insurance companies do not normally offer a reduction in premiums if “security” fl oodlights are fi tted, due to the lack of evidence that lighting reduces crime. The Home Of fi ce website’s statistics section states that 48% of the more than 284,000 properties broken into in the UK each year had “security” lights. The website also carries an interesting survey by Ian Hearnden and Christine Magill entitled “Decision-making by House Burglars – Offenders’ Perspectives.”

89Crime Reduction

Based on a sample of 82 offenders, the percentages of respondents rating the following factors as a deterrent to entering premises are:

Belief that house is occupied: 84% • Presence of alarms outside property: 84% • Presence of CCTV/camera near property: 82% • Apparent strength of doors/window locks: 55% • Evidence of membership of neighborhood watch or similar groups: 29% • Property marking campaigns: 25% • Local poster campaigns: 18% •

Other factors included convenient approach and exit routes, and there being a ready market for the goods. Nowhere in the report is the presence of lighting men-tioned as a deterrent.

Outdoor lights provide no information about whether or not a house is occupied, the biggest factor in fl uencing a criminal’s decision to break in. However, leaving a light on indoors , especially if timer-activated, can imply that premises are occu-pied, which is more off-putting to a potential intruder and at least fi ve times more energy-ef fi cient (assuming an indoor 100 W bulb as opposed to an outdoor 500 W bulb). “Security” lights themselves are often targeted by vandals, and in the words of Martin Morgan-Taylor, “lights in secluded areas are just that: nobody can see what the criminal is doing, and he has a courtesy light to illuminate his activities” (Fig. 5.4 ).

The National Institute of Justice in the United States published an assessment of crime and violence (see Bibliography ) in Preventing Crime: What Works, What Doesn’t, What’s Promising . The study found little support for the misconception that “brighter is safer,” and even suggested that poorly designed lighting might actually increase personal vulnerability. The report states: “The problematic rela-tionship between lighting and crime increases when one considers that offenders need lighting to detect potential targets and low-risk situations. Consider lighting at outside ATM machines, for example. An ATM user might feel safer when the ATM and its immediate surrounding area are well lit. However, this same lighting makes the patron more visible to passing offenders. Whom the lighting serves is unclear.” The Institute concludes: “…lighting has received considerable attention. Yet, evalu-ation designs are weak and the results are mixed. We can have very little con fi dence that improved lighting prevents crime.”

It is often argued that lights make people feel safer. This may often be true, but the relationship is in reality more complex. Glare, lack of uniformity and poor sit-ing of lamps reduce vision, and, especially in the elderly, can confuse and endan-ger. The increasing use of brighter, white lighting in the UK – new street lights are almost always white nowadays – is often justi fi ed by authorities claiming that they increase visibility and enable potential victims of crime to assess others at a dis-tance. Remember, however, the National Institute of Justice’s phrase: “whom the lighting serves is unclear” – a thief or mugger will fi nd it easier beneath such lights to assess the vulnerability of the potential target at a distance. Again – it works both ways.

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In 2002 the California Energy Commission found that lighting may have little correlation with a person’s perception of safety. A related study concluded that “lots of lights meant lots of glare (Fig. 5.5 ), which in turn increased fear of crime.” Heightening and stressing “fear of crime” makes money for the crime prevention industry. Should they be creating a false sense of security and suggesting people spend their money on ineffective lighting by stressing that the lighting reduces the fear of crime?

Does Darkness Inevitably Mean More Crime?

Ever since our distant ancestors crouched around their camp fi res, aware of the predators in the surrounding dark, people have associated light with safety and darkness with danger. We may, in the developed world, have largely eliminated the carnivores that wanted to eat us, but there are still malefactors out there. Can dark-ness help them and work against the potential victim?

Fig. 5.4 A “security” light in a secluded area may act as a “courtesy light” for criminals

91Crime Reduction

The author recently (2008) interviewed people in Wimborne, Dorset, England, asking them what they thought were the worst crimes that had occurred in that small, reasonably af fl uent and usually peaceful market town in recent times. The four most frequently mentioned incidents were two murders, both in the street, a ram-raid (Fig. 5.6 ), when a vehicle was reversed into a domestic electrical shop and goods stolen, and an armed robbery at a pharmacy. All (yes, all) these crimes occurred vertically beneath street lights. In three of the four cases, the lights were on, since the crimes were committed at night. One of the murders, however, occurred on a sunny morning, on a bridge across the river. This small local survey did not show a deterrent effect associated with light, either natural or arti fi cial. Anecdotal it may be, but it is undoubtedly echoed in towns everywhere. In neigh-boring Ferndown, a local church hall was trashed and property stolen one night – by the light of ten exterior lamps. One hesitates to call them security lights.

Here are some other items of interest from around the world:

During the power blackout that affected Auckland (New Zealand) for several • weeks in early 1998, criminals almost deserted the darkened streets. A police inspector remarked: “It’s been almost a crime-free zone. The normal levels of muggings, violence, fi ghts, burglary and robbery have just not happened.” Detroit, Michigan, a city with a high crime rate, experienced less crime than • normal during the power failure of August 2003, which lasted throughout the

Fig. 5.5 “Security” lights shining into the eyes of approaching drivers (Photo: CfDS)


night. Of fi cials stated that: “Police had fewer calls within the city of Detroit than on an average day, even with the blackout.” The International Dark-Sky Association reports that Dark Campus Programs, • involving lights being turned off at night, have reduced vandalism on school campuses: “School districts across the United States are turning conventional wisdom on its head by turning off lights in school grounds… It seems to work well… When everyone gets used to dark school grounds, lights of any kind will arouse suspicion.” The temple-like Penshaw Monument (1844) near Sunderland, England, was fi rst • fl oodlit in September 1988. Keeping the Victorian landmark lit is a continual headache for the local council, because the lights are constantly broken by youths after dark. In November 2000, the Liverpool Echo newspaper reported that night-time vandals had smashed 55 of the ground-level fl oodlights, switched on at the time, around the city center’s vast neo-classical St. George’s Hall. In the same report, a local councilor was quoted as saying, ironically, that she believed that lighting in the city center was “a crucial part of a Citysafe scheme to drive crime out of Liverpool.” Lights themselves can be the focus of crime. A survey in Houston, Texas, concluded that 72% of burglaries in that city occur • during daylight hours ( www.chron.com ). Figures for the UK vary between 45% and 68%, according to which source is consulted (police, Home Of fi ce, insurers, retailers of security devices). 55% seems a reasonable estimate.

Fig. 5.6 Site of a ram-raid, carried out by the light of a street lamp

http://www.chron.com

93‘Security’ Floodlighting: Anti-Lights

‘Security’ Floodlighting: Anti-Lights?

Retailers continue to offer 300–500 W domestic “security” lamps, much brighter than the ILP Guidance Notes recommend, 150 W being “more than adequate” for the ILP. The 500 W light is half the wattage of Britain’s brightest lighthouse, the Longstone. The retailers claim that their range of products respects the environ-ment, yet approaches to them by environmental campaigners have rarely been acted upon. PIR-activated fl oodlights are so frequently triggered that, when they come on, this is usually ignored by neighbors and passers-by, and is often not noticed by anybody indoors. Only one large UK retailer agreed to meet environmental groups, in 2009, and promised to ensure that instructions are placed in packaging advising on correct installation – but this retailer has not changed the designs of its lights, many of which are extremely wasteful. The UK Home Of fi ce, the UK Parliamentary Science and Technology Select Committee, and the Royal Commission on Environmental Pollution have all come out against 500 W lights, agreeing that they are invariably “over the top.”

IESNA de fi nitions of glare seem irrelevant to the manufacturers of such devices, which rarely include instructions on mounting angles and the avoidance of light intrusion, skyglow or glare. When bolted to an outside wall, the lights are often aimed indifferently towards the general area to be illuminated, with their front glass vertical or near-vertical, allowing as much as half the light to be emitted above the horizontal, across the street, well beyond the premises, and also into the sky.

If allowed to shine all night, they represent a major environmental problem, and use far more electricity than would a light of a more sensible wattage. The presence of such lights advertises the existence of the premises that they are supposed to protect, especially if they would normally not be seen from a distant road. When they are switched on, or, if fi tted with a PIR sensor, are triggered, the resultant glare (Fig. 5.7 ) has consequences beyond the erasure of the night sky and the increased totals on the electricity bill.

The main reason for the upsurge, reported by Environmental Health Of fi cers, in complaints involving light intrusion in the UK during the last decade, is not primar-ily that existing planning law does not encompass or seek to control small-scale outdoor lighting. The simple fact is that nearly all “security” lights on retailers’ shelves have not been designed with a view to trying to restrict their emissions to the premises to be lit (Fig. 5.8 ), which would involve the addition of shielding, baf fl es or louvers, and not least the inclusion in their packaging of instructions on sensitive mounting of these devices.

Sales of such poorly designed and environmentally insensitive “security” lights rocketed during the 1980s and into the 1990s, to the extent that describing them as “ubiquitous” is not far from the truth. Advertisements for these lights stress their value in deterring the approach of criminals, though the debate about the truth of such claims is intense. Certainly, premises possessing these “deterrents” are com-monly entered, robbed and vandalized at night, even when the lights are working. Our cities are ever more brightly lit, but this does not seem to result in a reduction


Fig. 5.8 An outside lamp with its sensor mounted beneath, making it impossible to angle it down further

Fig. 5.7 Glare: a poorly aimed light in rural Northern Scotland (Photo: Bill Eaves)

95‘Security’ Floodlighting: Anti-Lights

in urban crime, and premises in rural areas are regularly broken into whether or not exterior lights are fi tted.

By 1993, the passive infrared (PIR) sensor, activating the light if a heat source enters its fi eld of “view,” was becoming a common feature of such lamps. Sensor-triggered lamps were to some extent an improvement on their far more wasteful predecessors, which might be left on all night long. However, in many cases, the manufacturer mounts the sensor centrally below the lamp casing, which prevents the lamp being angled very far downwards even if its owner is mindful of prevent-ing spillage of light onto neighboring premises (see Fig. 3.4 ). Until about 30 years ago, many domestic outdoor lighting units had projecting rain-shields fi tted above the lamp housing, because their makers were not obliged to fi t glass to the front of the lamp. Now that glass is compulsory as a safety screen, the shield, which would prevent much upward light spill, has been done away with.

In October 2003 the UK Parliamentary Select Committee on Science and Technology called for an end to the retail of 500 W “security” lights, and for the nuisance that they cause to be classi fi ed as actionable in law. Such fl oodlights, with excessive high-wattage bulbs in them, impede the vision of both potential witnesses of crime and of CCTV cameras with their blindingly powerful light. Also, they create very dark shadows, thereby offering double concealment. An intruder is sup-plied with a light source, paradoxically far less likely to cause suspicion in the mind of any right-minded person in the vicinity than a hand-held, moving torch in a darkened area. These are indeed “anti-lights,” negating the whole point of a light, which is to reveal rather than conceal. Floodlights need to be pointed downwards to illuminate the area of interest. Even the slightest upward angle can render a “security” light useless and create light nuisance. The Campaign for Dark Skies’ interactive web page ( www.britastro.org/dark-skies/ fl oodlights.html?6O ) has some interesting images to illustrate this point.

Advice on ‘Security’ Lighting

Even the Institution of Lighting Professionals, a body promoting the interests of the lighting industry, says in its Guidance Notes for the Reduction of Light Pollution that for most domestic tasks, the 150 W full cut-off fl oodlight, correctly positioned with no light spillage, is the maximum wattage needed, and indeed recommends lower wattages: “For domestic and small-scale security lighting…, passive infrared detectors can be used to good effect, if correctly aligned and installed. A 150 W (2,000 lumen) tungsten halogen lamp is more than adequate. 300/500 W lamps create too much light, more glare and darker shadows. All-night lighting at low brightness is equally acceptable. For a porch light a 9 W (600 lumen) compact fl uorescent lamp is more than adequate in most locations.” So the experts are on the side of those who appreciate what well con fi ned, quality lighting means for the environment (Fig. 5.9 ).

http://dx.doi.org/10.1007/978-1-4614-3822-9_3

http://www.britastro.org/dark-skies/floodlights.html?6O


The Government’s Home Security/Crime Reduction website states “The form of lighting currently found on the overwhelming majority of domestic locations is a 250 or 500 W tungsten-halogen fl oodlight controlled by a movement sensor. This is unfortunate, as in many locations this is the most inappropriate form of lighting available.”

If you go out at night, leave a light on indoors instead of outdoors. Research by Bennett and Wright (see Bibliography ) into what motivates burglars concluded, after interviews with 300 experienced burglars, that their main concern was whether or not the premises were occupied. The presence or absence of outside lights did not enter into their consideration when deciding whether or not to break in. If an indoor light is on then there is a possibility of somebody being at home, but outdoor lights do not convey anything about who might or might not be there.

Consider whether fl ooding an area with light will cause more harm than good. Consider a completely dark environment − is it more likely that someone fl ashing a torch around in the dark will be noticed, and create more suspicion in the minds of witnesses than someone moving in a lit environment?

Or consider using low-powered lighting. According to the U.S. Army Corps of Engineers, CCTV cameras that are used day and night work best if the light contrast between the bright foreground and the dark background is less than 4–1; otherwise the CCTV images are dominated by glare.

Fig. 5.9 Low-power shielded exterior lighting illuminates a porch and garden adequately, without glare or spill into neighbouring premises (Photo: IDA)

http://dx.doi.org/10.1007/978-1-4614-3822-9_BM1

97Conclusions

Conclusions

Better, independent research is needed to quantify the effect of light on crime, and higher scienti fi c standards are required – especially as large amounts of money are spent on lighting in the hope of a reduction in crime. The only thing that can be said for certain is that the common assumption that light will always deter criminals is incorrect.

When lighting is installed, the question must be asked: “Who will bene fi t most from these lights? Victims? Witnesses? Criminals?” There is still no proven link between lighting levels and crime rates, due to the complex nature of the subject, and simplistic conclusions cannot hide the fact that crime is a societal problem, not a lighting problem .

If light is needed for other reasons (e.g., to help people use an area), then shielded lighting should be used, of minimum brightness and minimum duration. Remember that lighting, a comfortable night-time environment and dark skies need not be mutually exclusive. The use of modern full cut-off lights means lit areas are more satisfactory and attractive for all law-abiding people, with the likelihood of an optimum night sky.


Quantifying the Problem

Chapter 6

The adverse effects of poor quality lighting are plain for all to see, and a source of annoyance and concern to many. Those who wish to achieve the worthwhile goal of convincing legislators, local administrators, manufacturers and installers to follow good lighting practice should marshal their arguments carefully. Before presenting the case for improvement in this fi eld to those who can really change things, it is useful to have facts and fi gures ready, and to adopt a scienti fi c as well as a (rightly) emotional approach in favor of the environment and against wasted energy. This section attempts to provide such facts and fi gures.

Measurement

The measurement of the amount of skyglow above a given location is not easy, depending as it does on many variables.

An instrument now becoming popular with astronomers is the Sky Quality Meter (Fig. 6.1 ), for example the Unihedron SQM designed by Dr. Doug Welch and Anthony Tekatch. The meter is a small hand-held instrument, about the size of a TV remote control, which quanti fi es sky brightness. The instrument is held overhead and aimed at the zenith, and “sees” a cone of about 80° width of sky. The user must be careful not to allow any other light source into the cone. The meter will beep, and then a digital display shows a number, usually between 15 and 20 for most night-time observers.

A typical meter reading of 20 is obtained at a fairly dark site, and 15 represents a very light-polluted sky. So, the larger the number, the darker the sky. In 2009, in one of England’s darkest places, Exmoor in the southwest, David Brabban recorded a meter reading of 21.85 at Prayway Head (Fig. 6.2 ), making it one of the best

100 6 Quantifying the Problem

Fig. 6.1 A Sky Quality Meter

Fig. 6.2 The night sky at Prayway Head, Exmoor, SW England (Photo: David Brabban)

101Measurement

observing sites in the country. At Cherry Springs State Park dark-sky reserve in Potter County, Pennsylvania, in the United States, a remarkable reading of 23.27 was obtained in 2007 – truly dark!

Many people assume that arti fi cial light going skywards is merely that which is re fl ected from the ground. Anyone standing on a piece of high land overlooking a town or city can see, however, that most of the waste upward light comes from the lamps themselves (Fig. 6.3 ) rather than from the ground below the lamps. Yet a certain amount will always be re fl ected by any surface (roads, pavements, walls, windows) likely to be found in a built-up, lit area. Variables include the number, brightness and distance of the light sources on the ground, the percentage of their emissions that escapes above the horizontal, the upward re fl ectivity of surfaces in the vicinity of the sources, and the state of the atmosphere. Re fl ectivity is de fi ned as a measure of the ability of a surface to re fl ect radiation, equal to the re fl ectance of a layer of material suf fi ciently thick for the re fl ectance not to depend upon the thick-ness. Re fl ectance ( r ) is simply the ratio of the re fl ected fl ux to the incident fl ux.

The condition of the surface will also be a factor in its re fl ectivity. Is it clean or dirty? Dark or light? Rough or smooth? Re fl ective, absorbent or semi-transparent? Wet or dry? Estimates for this re fl ected amount average a few percent of the inci-dent light emitted from the source, but it is impossible to give a standard fi gure because of all the variables involved. David Coatham, Technical Services Manager at the ILP, said in a radio interview about light pollution in November 2000: “We can control light that goes directly upwards, but a lot of the light that goes down onto surfaces is re fl ected into the night sky and is very dif fi cult to control.” The answer to this, of course, is to put the right amount of light for the lighting task onto those surfaces, and the amount (inevitably) re fl ected into the sky will be minimized.

The organizations working to reduce light pollution know that, because of this re fl ection factor, the total eradication of skyglow over lit areas is not an achievable goal. Neither can we expect everybody to happily switch off all their lights. The necessary support from an educated public will never come if people think that astronomers and environmentalists want to plunge them all into utter, medieval darkness as soon as the Sun goes down.

The amount of skyglow seen from any location can vary noticeably with atmo-spheric conditions. Low cloud cover, even if very thin, is quite re fl ective, and will reveal the presence of sources of upward light beneath it (Fig. 6.4 ). A Dutch astronomer, H. E. Mostert, even invented a “clear sky detector,” a device that detects the waste light re fl ected from clouds. When the sky clears, causing the glow to diminish, the device can be programmed to emit an audible signal, possibly the only positive use that has ever been found for skyglow (see Bibliography ).

At the other end of the spectrum, there can be nights when even normally severe light pollution is considerably alleviated. It is often noticed by regular observers of the night sky that, after rain, the sky may seem clearer than usual, as it contains less suspended dust and other impurities. Very occasionally, when air quality changes due to the constant motion of air masses, sky transparency can increase markedly,

http://dx.doi.org/10.1007/978-1-4614-3822-9_BM1


Fig. 6.4 Re fl ection from a thin veil of low cloud over Edinburgh (Photo: Chris Baddiley)

Fig. 6.3 This view of Malvern and Worcester taken from nearby hills shows plainly that most of the waste light comes from the luminaires, not from the ground (Photo: Chris Baddiley)

103The Bortle Scale

with upward light being re fl ected and scattered to a much lesser degree (Fig. 6.5 ). But there is no such thing as a completely transparent atmosphere, which would allow light passing through it to continue its journey without encountering particles and droplets.

The Bortle Scale

In February 2001, John Bortle published his now famous light-pollution scale in Sky & Telescope magazine, to help observers judge the true darkness of a site. It is based upon the actual visibility of given night-sky objects, and what might be seen through a standard (32-cm) telescope. It is reproduced here with his permission.

Fig. 6.5 Ideal atmospheric conditions: a crystal-clear winter sky over central Dorset


Class 1: Excellent Dark-Sky Site

The zodiacal light, Gegenschein, and zodiacal band are all visible – the zodiacal light to a striking degree, and the zodiacal band spanning the entire sky. Even with direct vision, the galaxy M33 is an obvious naked-eye object. The Scorpius and Sagittarius region of the Milky Way casts obvious diffuse shadows on the ground. To the unaided eye the limiting magnitude is 7.6–8.0 (with effort); the presence of Jupiter or Venus in the sky seems to degrade dark adaptation. Airglow (a very faint, naturally occurring glow most evident within about 15° of the horizon) is readily apparent. With a 32-cm (12½-in.) ‘scope, stars to magnitude 17.5 can be detected with effort, while a 50-cm (20-in.) instrument used with moderate magni fi cation will reach 19th magnitude. If you are observing on a grass-covered fi eld bordered by trees, your telescope, companions, and vehicle are almost totally invisible. This is an observer’s Nirvana!

Class 2: Typical Truly Dark Site

Airglow may be weakly apparent along the horizon. M33 is rather easily seen with direct vision (Fig. 6.6 ). The summer Milky Way is highly structured to the unaided eye, and its brightest parts look like veined marble when viewed with ordinary binoculars. The zodiacal light is still bright enough to cast weak shadows just before dawn and after dusk, and its color can be seen as distinctly yellowish when compared with the blue-white of the Milky Way. Any clouds in the sky are visible only as dark holes or voids in the starry background. You can see your telescope and surroundings only vaguely, except where they project against the sky. Many of the Messier globular clusters are distinct naked-eye objects. The limiting naked-eye magnitude is as faint as 7.1–7.5, while a 32-cm telescope reaches to magnitude 16 or 17.

Class 3: Rural Sky

Some indication of light pollution is evident along the horizon. Clouds may appear faintly illuminated in the brightest parts of the sky near the horizon but are dark overhead. The Milky Way still appears complex, and globular clusters such as M4, M5, M15, and M22 are all distinct naked-eye objects. M33 is easy to see with averted vision. The zodiacal light is striking in spring and autumn (when it extends 60° above the horizon after dusk and before dawn), and its color is at least weakly indicated. Your telescope is vaguely apparent at a distance of 20 or 30 feet. The naked-eye limiting magnitude is 6.6–7.0, and a 32-cm re fl ector will reach to 16th magnitude.

105The Bortle Scale

Class 4: Rural/Suburban Transition

Fairly obvious light pollution domes are apparent over population centers in several directions. The zodiacal light is clearly evident but doesn’t even extend halfway to the zenith at the beginning or end of twilight. The Milky Way well above the hori-zon is still impressive but lacks all but the most obvious structure. M33 is a dif fi cult averted-vision object and is detectable only when at an altitude higher than 50°. Clouds in the direction of light pollution sources are illuminated but only slightly so, and are still dark overhead. You can make out your telescope rather clearly at a distance. The maximum naked-eye limiting magnitude is 6.1–6.5, and a 32-cm re fl ector used with moderate magni fi cation will reveal stars of magnitude 15.5.

Class 5: Suburban Sky

Only hints of the zodiacal light are seen on the best spring and autumn nights (Fig. 6.7 ). The Milky Way is very weak or invisible near the horizon and looks rather washed out overhead. Light sources are evident in most if not all directions.

Fig. 6.6 The night sky over Sark, the Channel Islands’ dark-sky preserve. Only a few distant house lights (exaggerated on this exposure) intrude into a pristine sky (Photo: Martin Morgan-Taylor)


Over most or all of the sky, clouds are quite noticeably brighter than the sky itself. The naked-eye limit is around 5.6–6.0, and a 32-cm re fl ector will reach about magnitude 14.5–15.

Class 6: Bright Suburban Sky

No trace of the zodiacal light can be seen, even on the best nights. Any indications of the Milky Way are apparent only toward the zenith. The sky within 35° of the horizon glows grayish white. Clouds anywhere in the sky appear fairly bright. You have no trouble seeing eyepieces and telescope accessories on an observing table. M33 is impossible to see without binoculars, and M31 is only modestly apparent to the unaided eye. The naked-eye limit is about 5.5, and a 32-cm telescope used at moderate powers will show stars at magnitude 14.0–14.5.

Fig. 6.7 Suburban night sky: Orion in a light-polluted winter sky

107The Bortle Scale

Class 7: Suburban/Urban Transition

The entire sky background has a vague, grayish-white hue. Strong light sources are evident in all directions. The Milky Way is totally invisible or nearly so. M44 or M31 may be glimpsed with the unaided eye but are very indistinct. Clouds are bril-liantly lit. Even in moderate-size telescopes, the brightest Messier objects are pale ghosts of their true selves. The naked-eye limiting magnitude is 5.0 if you really try, and a 32-cm re fl ector will barely reach 14th magnitude.

Class 8: City Sky

The sky glows whitish gray or orangish, and you can read newspaper headlines without dif fi culty (Fig. 6.8 ). M31 and M44 may be barely glimpsed by an experi-enced observer on good nights, and only the bright Messier objects are detectable with a modest-size telescope. Some of the stars making up the familiar constella-tion patterns are dif fi cult to see or are absent entirely. The naked eye can pick out stars down to magnitude 4.5 at best, if you know just where to look, and the stellar limit for a 32-cm re fl ector is little better than magnitude 13.

Fig. 6.8 Light over a big city (Photo: Chris Baddiley)


Class 9: Inner-City Sky

The entire sky is brightly lit, even at the zenith. Many stars making up familiar constellation fi gures are invisible, and dim constellations such as Cancer and Pisces are not seen at all. Aside from perhaps the Pleiades, no Messier objects are visible to the unaided eye. The only celestial objects that really provide pleasing telescopic views are the Moon, the planets, and a few of the brightest star clusters (if you can fi nd them). The naked-eye limiting magnitude is 4.0 or less.

New Lamps for Old

When discussing the causes of, and solutions to, the problem of light pollution, it is best to know a little about the lights themselves! This section attempts to give some basic facts about lighting, luminaires (the lamp assemblies) and good practice.

What is the cost of operating a street light? Street lighting luminaires vary greatly, in lamp types and power consumption

(typically between 35 and 250 W). The average cost of operating a streetlight, including energy supply and maintenance, is currently between £30 and £50 per year (at the time of writing, mid-2011, £1 = $1.65), according to various UK local authority websites.

An example taken from the many to be found on the Internet is that of Moray Council in Scotland. Moray is a mainly rural area of NE Scotland with a popula-tion of about 90,000. In 2011, the council published fi gures stating that the average energy cost of each of their streetlights in 2010/2011 was £32.29, while mainte-nance came to £15.15 – a total of £47.44 per light for the year; so in 2010/2011, its 17,033 streetlights cost the rate-payers just over £800,000 ($1.3 million) to operate. This can be expressed as a cost of nearly £9 ($14.85) a year for each inhabitant.

In his Brie fi ng Sheet on Road Lighting and Highway Power Supplies (1992), lighting engineer Joseph Knowles stressed the two most important points that need to be taken into consideration to ensure good quality lighting: “Pollution can be obviated by well-designed lighting installations incorporating advanced optical control systems directing light below the horizontal…with the lowest intensity light source that can achieve the requisite luminance performance.” The ILP expressed this more simply in its Guidance Notes (2010): “Obtrusive light, whether it keeps you awake through a bedroom window or impedes your view of the night sky, is a form of pollution and can be substantially reduced without detriment to the lighting task” (Fig. 6.9 ).

Basically, those making, choosing and installing luminaires need to use the capability of internal re fl ecting surfaces (the optical system) and the lamp glass to

109Types of Lamps

direct the emissions to the area to be lit, the mounting height also being relevant here; and the light source within the casing needs to be of the minimum brightness necessary to perform the lighting task adequately.

Nowadays, it is not dif fi cult to fi nd, in the arti fi cially lit environment, luminaires that conform to these ideals. There are, sadly, still far too many which manifestly do not. What are the most common lamp types?

Types of Lamps

The majority of lamps used nowadays in public lighting are of the high - intensity discharge type, which have compact arc tubes. Lamps with longer tubes will prob-ably be of the low-pressure sodium type (see below). Private lighting, which nor-mally involves the fl oodlighting of premises for commercial or security purposes, often involves tungsten-halogen or metal halide lamps as well as sodium.

Fig. 6.9 A decorative LED light on the Clifton Suspension Bridge in Bristol: shielded and not too bright for the task (Photo: Pam Mizon)


Sodium Lamps

In the 1960s, the typical streetlight in the UK was a low-pressure sodium (LPS, sometimes called SOX) type (Fig. 6.10 ). LPS sources are usually long (up to a meter) and of a bold yellow-orange hue. These were largely replaced during the last decades of the twentieth century by high-pressure sodium (HPS, sometimes called SON), with their smaller casings and pinkish-orange light. The terms high-pressure and low-pressure are relative, because the gases in the discharge tubes that ionize to form a discharge are always below atmospheric pressure.

Monochromatic LPS light gives a rather “muddy” and uniform look to surfaces, with poor rendition of their actual color, while HPS light gives a truer perception. HPS lamps typically use higher wattages than LPS.

The length of LPS lamps made them dif fi cult to enclose, so their light was not as easy to direct as light from the smaller HPS source. The monochromatic LPS emis-sion was preferred by some astronomers, who rightly stated that it is easier to deal with by using a sodium fi lter than is HPS light, with its many combined wave-lengths. However, the enormous majority of those who enjoy the sight of the night sky, astronomers or otherwise, do not possess such fi lters. For them, the direction in which the light is made to travel, and its intensity, are the most important factors, and HPS scored over LPS in these aspects. The argument is rapidly becoming academic, as white-light types (see below) replace sodium lights all over the developed world.

Fig. 6.10 Old LPS road lights of the kind which are (at long last) fast disappearing in the UK (Photo: Chris Baddiley)

111Types of Lamps

In many countries, the trend since the mid-1990s has been for the replacement of sodium lamps with “whiter-light” types.

Mercury Lamps

In limited applications, for example where very accurate color rendering is needed, high-pressure mercury vapor (MBFU) lamps are used. Usually seen as a “white light” source, such lamps are often used for illuminating traf fi c signs, though they produce typically only 50 lumens per watt of blue-white light, half that of the old LPS lamps. The IDA reports that some Arizona lighting ordinances (e.g., in Tucson and Pima County) prohibit the installation of new mercury lamps, on the grounds of their inef fi ciency. Their relatively low ef fi cacy in converting electrical power into light is to some extent compensated for by their longevity. Low-pressure mer-cury (MCF) types are occasionally met with for some tasks where a lower level of light is required, but mercury lamps generally have fallen out of favor nowadays in most outdoor applications. If you see a mercury lamp nowadays, it will probably have been in situ for many years.

Metal Halide Lamps

A bluish-white high-pressure discharge source, and more energy-ef fi cient than mercury lamps, metal halide lamps (Fig. 6.11 ) are probably the primary sources used nowadays for white light. As the use of white light for functional and decora-tive purposes grows, they are increasing in popularity at the expense of sodium lamps. They are now frequently seen on our roads, and are common in such appli-cations as car park lighting and the illumination of commercial premises. Wattages used are often too high, giving a harsh, overlit effect that the IDA has dubbed “prison-yard” lighting. If not well shielded, they can cause considerable glare and deep shadows. Light re fl ected from the ground will also be increased if they are too bright for the lighting task, exacerbating skyglow.

Tungsten-Halogen Lamps

These white-light arc or fi lament lamps, only a little more ef fi cient than the incandes-cent bulbs that light most of our houses, are the main culprits when glare is experi-enced from the outside walls of domestic premises. Relatively short-lived, they are the preferred light source for fl oodlights and spotlights. Typical values for domestic secu-rity fl oodlights are 300 and 500 W, both far too bright for the task of illuminating the average small garden or driveway. Drivers and passers-by dazzled by a domestic exte-rior light a hundred meters away are usually victims of a tungsten-halogen lamp.


Fluorescent Lamps

We are all familiar with the long low-pressure discharge tubes of fl uorescent light-ing, more commonly associated with interiors. The dimensions of fl uorescent lamps mean that the direction of their emissions is not easily controlled, though glare is less of a problem. The rapid development of compact fl uorescent (CFL) sources means that these lamps will be seen more often in the future for outdoor applica-tions, though their use will probably be restricted to areas such as residential streets in rural areas where high lighting levels are not required; a typical wattage for a compact fl uorescent source is 55 W.

LEDs

LEDs are all the rage in lighting circles nowadays (Fig. 6.12 ), and there is consider-able investment in their development. In January 2009, researchers at Cambridge University developed an LED bulb that costs £2 (about $3), is 12 times as energy-ef fi cient as a tungsten bulb, and lasts for 100,000 h. It is estimated that the lumen output of LEDs is doubling every 2 years. They are likely to become major “play-ers” in many applications of outdoor lighting.

Fig. 6.11 New metal halide road light in a seaside town: note the “mast”-style column

113Types of Lamps

Globe Lights (Spheres)

Leave through the back door of 19 New King Street, Bath, and you step into the garden where William Herschel doubled the size of the Solar System overnight, on March 13, 1781, when he discovered the planet Uranus through his “7-foot re fl ector” (the fi gure refers to the focal length). The great man’s house, where he lived with his sister Caroline, also an accomplished astronomer, is nowadays a splendid museum. It has recently been beautifully refurbished, but the garden was long ago shortened by the intrusion of later building.

Opposite the garden door stands a statue of William and Caroline, he staring sternly into the heavens, towards the place where the new planet fi rst caught his eye

Fig. 6.12 A triply environmentally friendly LED light: well-directed, solar powered, and it goes off when there is nobody around! (Photo courtesy of Zeta Solar)


at the telescope, while his sister carefully records observations (Fig. 6.13 ). Were the Herschels to return to New King Street today, though, they would be less likely to discover a new planet; nor would they see many stars over the far end of their gar-den, for there is now a supermarket, a shopping complex and a parking lot there; and these are at present lit by globe lights (Fig. 6.14 ). Some are uncapped and send their emissions into the sky.

Seldom seen along roads, globe lights, sometimes called spheres or opal spheres, were becoming very popular in the 1980s and early 1990s for public areas such as parking lots, walkways and shopping centers. Globes contain light sources of vari-ous kinds, often with little or no shielding, and more than half of the emissions from these (unshielded) sources will go skywards, since the sphere is mounted on a cra-dle atop the supporting column, which prevents light from passing directly down-wards from the lamp to the area around the base of the column. A person standing close to such a lamp is, paradoxically, not as well illuminated as somebody further away. When they are erected close to buildings, much of the poorly controlled light

Fig. 6.13 The statue of William and Caroline Herschel in their garden, close to the spot from which Uranus was discovered (Photo: Mike Tabb)

115Types of Lamps

from globes can enter upper-storey windows, and even more of it will, of course, end up in the night sky. Figure 6.15 shows the result of the exasperation people can feel when such uncontrolled light pours into their bedroom window!

Globe lights are good examples of luminaires chosen more for their daytime appearance than for their night-time ef fi ciency. The effect of massed globes, on sites where environmental considerations have been sacri fi ced for decoration, is shown in Fig. 6.16 . This photo shows skyglow caused by nearly 90 unshielded globe lights erected in the fairly small town of Newport, Shropshire, in 1993, in the parking lot of a large new supermarket. The lights all but obliterated the night sky over the town. In this case, swift intervention by members of the CfDS led to the capping of the lights, at comparatively little expense to the national supermarket chain involved, though it would of course have been more economical to have chosen better lighting in the fi rst place.

Even globe lights can be made to perform in a more environmentally responsible way, if a little thought is given to their design. Internal louvers can be stacked within the sphere around the lamp, directing all the light downwards, though a small per-centage will be re fl ected upwards and outwards by the inner surface of the sphere (see next section). Figures 6.17 and 6.18 show the poor performance of a globe light: as the woman standing near the light moves in towards it, she becomes less visible. Figure 6.19 is a striking example of the poor light distribution from a globe light in a parking lot: the pool of relative darkness beneath the light is very obvious.

Fig. 6.14 Globe lights now illuminate the area behind the Herschels’ garden


Fig. 6.16 Newport, Shropshire: the stars I learned in boyhood are veiled by a supermarket’s car park globe lights (since capped)

Fig. 6.15 A globe light painted black on one side in an attempt to retrieve darkness for an upper-storey bedroom

117Types of Lamps

Fig. 6.17 A woman stands near a globe light and is easily seen (Courtesy IDA)

Fig. 6.18 The woman seen in Fig. 6.17 has moved into the less illuminated space beneath the globe light (Courtesy IDA)


Much of the light that should be illuminating the surface below is in fact being thrown upwards into the sky.

In informal conversations with lighting professionals, it becomes clear that unshielded globe lights are falling out of fashion these days. The sooner they are history, the better.

Shielding and Directional Adaptation in Luminaires

It is not intended that this non-technical book go into too much fi ne detail of how lamps are designed and engineered to shine preferentially downwards – it certainly isn’t as easy as it sounds! Most astronomers who are interested in minimizing light pollution care more about where the light goes rather than about how it gets there. Anyone who wants to explore the minutiae of luminaire design should contact the IESNA ( www.iesna.org ), or ILP ( www.theilp.org ) or order the lighting manufactur-ers’ descriptive sales catalogs, which often carry diagrams of the luminaires’ re fl ective optical surfaces.

All that is needed here, in order to give pertinent information that might be use-ful in discussion, are a few facts about the nature of these re fl ective surfaces above

Fig. 6.19 The fact that most of the light from this car park globe goes up instead of down is excellently illustrated by this IDA photo

http://www.iesna.org

http://www.theilp.org

119Shielding and Directional Adaptation in Luminaires

and around the light source; they are responsible for the intensity of the distribution of the light emitted, while the glass sheet or bowl/globe through which the light passes out into the environment creates further effects.

Optical directors in luminaires can be compared, in a way, to the optics of tele-scopes. Consider a telescope forming an image of a star. Light from a star enters the telescope as a parallel beam of light and is imaged to a point. Stars in different parts of the fi eld of view form separately located images at the focal plane of the telescope.

An optical system in a luminaire is rather like a telescope working backwards. For a well-directed luminaire, a point source at the focus of the optical system will be imaged to a parallel beam or a deliberately diverging one; the smaller and more point-like the light source is, the better the directionality of the beam. Luminaire optical systems should be designed to spread the light as evenly as possible over a de fi ned area. The re fl ector is over the light source, and the light source needs to be as small as possible to give the tightest distribution of beam, as in the case of the smaller high-pressure sodium bulbs. This is why such optical systems are rarely used on long low-pressure sodium tubes, though there are exceptions, and low-pressure sodium full cut-off lights do exist, as mentioned above.

The luminaire’s re fl ector behaves rather like a parabolic mirror in a telescope, turning the upward light from the lamp into a downward cone. The light that shines directly down from the bulb is similarly restricted by extending the mirrored sides down to below the level of the bulb and to a cut-off point that restricts the sideways light. A further re fi nement is a re fl ective spot directly below the bulb, to direct downward light back towards the re fl ector above. This redirects the otherwise most intense part of the beam, to add to the evenness of the illumination.

Asymmetric re fl ectors are used to direct the beam out towards the center of the road, with less light falling nearer to the lamp column. Varying degrees of asym-metry are used, according to whether the luminaire has to illuminate the whole width of the road, or just one side.

Cylindrical or globe lamps and bollard lights, often seen in parking lots and along walkways, sometimes use louvers (Fig. 6.20 ) to turn the light preferentially downwards. One problem here is that the louvers are sometimes quite re fl ective (unlike those in the example shown), resulting in multiple re fl ections between adja-cent louvers. The beams then spread out from the surface of last re fl ection. The ef fi ciency of such louver lamps varies, but they are certainly an improvement on types with no director at all. All glass surfaces introduce an internal re fl ection of about 10% of the light, which then exits in some other direction. Of course, capping globes with light-proof hemispheres will prevent much upward light, and many manufacturers produce accessories allowing lamps to be “retro- fi tted,” i.e., altered in design after installation.

Some capped cylindrical and globe lights also use arrays of small prisms to refract otherwise upward components downwards. Again there is the multiple re fl ection problem, and the scatter from the prismatic screens, if optically very imperfect, is signi fi cant, still giving sideways and upward waste light. On more


typical streetlamps, the design of bowls slung beneath the light source is important: the more curved the glass bowl, the more widespread the beam will be. Some lumi-naires labeled “full cut-off” (FCO) have deep bowls, and these produce a secondary image of the light source well below the level of the cut-off and can be seen at a range of angles. A true FCO light should restrict all light to below the horizontal.

Mounting angles are also important in cutting down skyglow. Some shallow-bowl or fl at-glass luminaires, which would normally emit little or no light above the horizontal, can cause skyglow and glare if they have been mounted with the glass at an angle well above the horizontal. If your local lighting provider tells you that “non-polluting” lights are to be installed, check that they will be installed at an appropriate angle. If cut-off lights are installed on a slope, will their glass still be truly horizontal?

There is always a “best light” for the lighting task, and any manufacturer worthy of the name ought to be able to give expert advice on which is the best luminaire to use to prevent light spill and skyglow.

Fig. 6.20 Stacked louvres con fi ne the light from this bollard lamp to the ground (Courtesy DW Windsor Lighting)

Piercing the Veil: Techniques and Targets

Part II


Techniques

Chapter 7

Educating the general public about responsible lighting is a massive undertaking for those who value the environment above. Telling your own neighbors about it can also be a daunting prospect. When the International Dark-Sky Association and the BAA Campaign for Dark Skies began their work in 1988 and 1989, respectively, the concept of “light pollution” certainly existed in the minds of astronomers, envi-ronmentalists and the lighting community, but almost no-one else had heard of the term. It is now in the general vocabulary, but the perception of the role of light at night is still dominated in many minds by the idea of “the more light, the better.”

It is quite possible to present a whole range of arguments about economy, effect on crime, and protecting the environment to the owner of a “Rottweiler” light, and still be told that “I feel better with it on, though.” It can be dif fi cult to convince ner-vous “light junkies” of the ill effects they can in fl ict upon others and upon their wal-lets, and in Part III, we shall look at strategies for educating about light pollution.

Depending on an astronomer’s location, and on the perceptions and degree of co-operation of neighbors, he or she may have a night sky full of interesting and attainable objects, or have to contend with skies fl ooded with arti fi cial light. Most observers probably experience something in between. Those who have ceased going out at night altogether, defeated by local lights, ought perhaps to reconsider: they should not only be looking for new ways, through campaigning and education, to try to achieve longer-term solutions, but also be taking a fresh look at what may still be seen through the veil of wasted light.

The most obvious courses of action for the frustrated observer whose instru-ments fail to show fainter objects in a tainted night sky are:

Try to fi lter out the offending light; • Invest in imaging equipment (a CCD camera) that, with the aid of computer • technology, will help to pierce the veil;

124 7 Techniques

Observe only relatively bright targets. There are plenty of books on observing • the Sun, Moon and planets, but many more remote objects can still be seen through moderate light pollution, with adequate equipment and in calm condi-tions, using more traditional methods only.

We’ll discuss fi lters and CCD equipment fi rst, and then offer some targets that do not need the high-tech approach.

Filters

There is a bewildering array of advertisements for fi lters in the astronomical press. Many of them promise that the products will reduce light pollution. Filters, which work by blocking unwanted light and admitting light in a fairly narrow region (bandwidth), can be effective devices, but if the object observed emits a proportion of its light outside the bandwidth, it will be dimmed. Remember always that fi lters subtract light; they do not add it, so they will not “brighten” the objects you want to look at. Figure 7.1 shows some popular LPR fi lters.

Light Pollution Reduction (LPR) fi lters are just that: they are not Light Pollution Elimination fi lters. They will not magically clear the sky, or restore it to its pristine

Fig. 7.1 Some LPR fi lters (Courtesy Ninian Boyle, Venturescope)

125Filters

state, though they can improve your view of certain objects, in dark skies as well as in light-polluted ones. They may not remove all the effects of light pollution, but by reducing them they can improve the visibility of some deep-sky targets, increas-ing the contrast between them and the background sky.

The three types of LPR fi lters are broad-band, narrow-band and line (extremely narrow-band) fi lters.

Broad-Band LPR Filters

These are designed to prevent the passage of light from the most common lamp types, namely HPS, LPS and mercury vapor; any light of the same nature coming from an astronomical object will also be removed. Broad-bands have bandwidths typically greater than 30 nm, measured at the “half-maximum,” or 50% transmis-sion level. Bandwidths for some popular broad-band fi lters are: Orion Skyglow, 85 nm; Lumicon DeepSky, 68 nm; Celestron A, 47 nm.

Sodium lamps produce yellow light centered on the so-called Na-D line at 589 nm, so the reddish or bluish light of nebular objects is not blocked. HPS sources emit a much wider range of wavelengths than LPS. Mercury lamps produce a variety of emissions, mostly below 450 nm and above 550 nm. Deep-sky objects such as galaxies and clusters, whose light consists mostly of starlight, are usually little enhanced by LPR fi lters. The objects that show up better tend to be emission nebulae such as the planetary nebulae (e.g., M57, the Ring Nebula) and supernova remnants (e.g., NGC 6992-5/6960, the Veil Nebula). Some old LPR fi lters block out only LPS light.

Narrow-Band Filters

Marketed as “Ultra High Contrast” (UHC) or “Ultrablock” fi lters, these have band-widths typically smaller than 30 nm. Bandwidth values for some popular narrow-band fi lters are: Lumicon UHC, 27 nm; Orion Ultrablock, 24 nm.

Line (Very Narrow-Band) Filters

These are normally of the Oxygen-III (O-III) or Hydrogen-Beta (H b ), and perform well on non-stellar objects. Their bandwidths are very restricted, and they reject nearly everything but one or two given emission lines. Bandwidth values for two popular types are: Lumicon O-III, 11 nm; Lumicon Hydrogen-Beta, 8 nm.

126 7 Techniques

So which fi lter to choose for your favorite planetaries, star clusters and galaxies? Table 7.1 (based on David Nash’s Internet LPR Filter guide) will help. In the table, performance ratings range from 1 to 6, meaning:

1: V ery poor. Object looks much worse than it would without the fi lter. 2: P oor. Object noticeably worse than without fi lter. 3: F air. Object about the same, or even a little better. 4: G ood. Object normally looks appreciably better. 5: E xcellent. Object normally looks dramatically better. 6: O utstanding. Object normally looks dramatically better even in conditions of

low light pollution (e.g., dark rural site).

So, for enhancement of emission nebulae and better subtraction of light pollu-tion generally, narrow-band fi lters are the way to go. Galaxies, stars and star clus-ters show better through a broad-band fi lter, though the bene fi ts are more subtle.

Interestingly, airglow, which emits predominantly at 465, 558, 630 and 636 nm, can also be subtracted by various fi lters, which explains why they can also enhance objects, especially those of low surface brightness such as the Veil Nebula in Cygnus, from dark observing sites. Most narrow-band fi lters will deal with the 465 nm line; all fi lters block the 558 nm line; fi lters that perform well on the red 630 and 636 nm lines include the Orion Ultrablock and, to a lesser extent, the Lumicon UHC and the Lumicon DeepSky.

Words of warning: LPR fi lters are very re fl ective, so take care to block out stray light from behind and beside you. Eyecups from binoculars can be useful here, or, if you don’t mind looking like a nineteenth-century photographer, drape a thick black cloth over your head and the eyepiece. Also, if instead of attaching the fi lter to your eyepiece, you are holding it between fi nger and thumb for “blinking” pur-poses, moving it rapidly to and from the eyepiece to compare views of nebulae, be sure to keep it parallel to the eyepiece lens. Tilting the fi lter will affect performance, as you can demonstrate to yourself by looking at a light though it and watching its color change with the angle of the fi lter as you slowly rotate it.

As in many aspects of astronomy, experience and practice count for much when using fi lters. Before trying your newly bought fi lter on a faint, challenging object, try something more attainable. The Great Orion Nebula or the Lagoon Nebula are ideal for fi nding your way with fi lters. Let con fi dence and success come in easy stages.

Table 7.1 Filters and performance

Object Broad-band fi lter Narrow-band fi lter Line fi lter

Planetary nebulae 3–4 5–6 6 a Other emission nebulae 3–4 5–6 6 a Re fl ection nebulae 2–3 2 1 Stars, clusters 2 1–2 1 Galaxies 2–3 1–2 1

a Normally, some emission nebulae have emission pro fi les that favor certain line fi lters. Planetaries tend to be rich in O-III emissions, while other types of emission nebulae are rela-tively stronger in Hydrogen-Beta

127CCD Astronomy

As an infrequent user of fi lters (they have a way of escaping from my small observatory [Fig. 7.2 ], never to be seen again), I am indebted to David Nash (United States) and Steve Tonkin (UK) for much of the up-to-date advice and information above. Their informative websites are listed in the Bibliography. You can fi nd articles on popular fi lters in Astronomy , February 1991, in Sky & Telescope , July 1995, on David’s website, and in Steve’s book Astro FAQs (also in the Bibliography).

CCD Astronomy

Those able to invest in a CCD (charge-coupled device) camera, used in conjunction with a telescope, automatic guiding equipment and computer back-up, can achieve stunning images of night-sky objects even from light-polluted urban sites. The pos-sibilities opened up by the image processing CCDs allow have rekindled interest in astronomy for some urban observers. A detailed discussion of how CCDs work is outside the scope of this book; there are excellent books available on CCD tech-niques (see Bibliography ).

Computer-processed CCD images taken nowadays from urban areas (Figs. 7.3 and 7.4 ) can rival photographs obtained in earlier decades at the world’s great

Fig. 7.2 My small run-off-roof observatory in Colehill, with its 21-cm/8.5-in. re fl ector

http://dx.doi.org/10.1007/978-1-4614-3822-9_BM1

128 7 Techniques

Fig. 7.3 Urban CCD image of M27, the Dumb-bell Nebula (Photo: Nik Szymanek and Ian King)

Fig. 7.4 Urban CCD image of M13, the great globular cluster in Hercules (Photo: Nik Szymanek and Ian King)

129CCD Astronomy

observatories, and CCDs have allowed many amateur astronomers to make their mark at the leading edge of astronomical research.

However, even the most dedicated and successful CCD user would likely agree that the products of modern technology, though they can counter the effects of light pollution for the individual through indirect viewing, do not solve astronomy’s problem, and our direct experience of the heavens with the naked eye and with small, more traditional instruments is worth fi ghting for.


Targets

Chapter 8

The great majority of amateur astronomers, and just about all of those youngsters across the world who have yet to discover the delights of our oldest science, possess neither fi lters nor CCD equipment and live beneath tainted skies. Yet there has been an upsurge in interest in astronomy among the general public in the last few years, due mainly to popular television programs and Hubble Space Telescope images.

Today’s amateur astronomers, as well as those with greater experience but mod-est equipment, need not be discouraged by the lack of a pristine night sky. Ef fi cient optical aid and some reference material (see Bibliography at the end of this book), will reveal a wealth of interesting objects, apart from the Moon and the planets, which can still be enjoyed through moderate light pollution, without fi lters: double stars of striking colors; bright though neglected clusters; curious star fi elds; vari-ables; even stars whose motion through our galaxy you can actually follow – the list is long. Below is a selection of 100 such objects, visible from northern mid-latitudes, seen and recorded beneath a moderately light polluted sky (Fig. 8.1 ).

Each object in the list contains a brief, and sometimes subjective, description, with observing details. The more experienced observer, who may be already famil-iar with some of these objects, knows that there are far more to be found. Forty years’ observing from back-garden sites in places as different as the East End of London and the underpopulated rural county of Shropshire have convinced this author that, whether the sky is baleful orange or coal-black, there’s always some-thing new to reward the adventurous searcher.

Deliberately included are some objects in constellations lying far down in the south from mid-northern latitudes. This was just to make the point that even down there, it’s worth searching on the best nights for the new and unusual in what might be considerable skyglow, unless you happen to be looking directly into the glare of a nearby lamp.

http://dx.doi.org/10.1007/978-1-4614-3822-9_BM1

132 8 Targets

When observing the listed objects, I used, unless otherwise stated, the venerable and still very serviceable 21-cm (8.5-in.) Charles Frank f/6 re fl ector shown in the photo (Fig. 8.2 ), with its Swift eyepieces of powers ×26 (achromatic Huyghenian), ×50 (Kellner), ×108 (Kellner) and ×323 (orthoscopic), sometimes in tandem with ×2 and ×3 Barlow lenses. Its excellent optics and sturdy construction ensure sharp, steady images rivaling those seen in more modern instruments of similar aperture.

All these observations were made during the years when the all-night lighting (Fig. 8.3 ) in this author’s street was of an extremely wasteful type. Known famil-iarly by lighting professionals as ‘post-tops,’ the local LPS lights threw about 30–40% of their emissions skywards, and the nearest one to my observatory was 30 m (about 100 ft) away. It was a great day (with many great nights to follow!) when my local council, whose attitude towards environmentally sensitive lighting became progressively more forward-looking during the 1990s, replaced all the streetlights in my area in 1998 with well-directed types, including full-cut-off lumi-naires (Fig. 8.4 ) to replace the two post-tops nearest my observing site. These in their turn have been replaced by metal halide types (Fig. 8.5 ), very well directed, and the three luminaires nearest to my garden have been shielded (Fig. 8.6 ) by the local council. So the streetlights in my road now shine where their light might con-ceivably be needed, and, like many others throughout the UK, go off at midnight. Dialog with your local lighting engineer about shielding can pay, in the generally positive climate that seems to be developing among lighting professionals.

Fig. 8.1 What a third of a million people throw into the sky: light pollution over Poole and Bournemouth

133Targets

Good-quality lighting can work wonders for astronomy. When new, better lights are installed, fainter stars become visible and redraw the constellations (Fig. 8.7 ), and naked-eye detail – dark rifts and bright projections – became apparent in the usually elusive Milky Way; in the south, the Scutum star cloud, several degrees below the celestial equator, can become occasionally visible on really clear, calm nights. This last phenomenon suggests that even just localized better lighting can cause considerable sky improvement in all directions, even if a whole city hasn’t been relit.

After each constellation name in the selection below is the best time of year to see the suggested objects at their highest in the late evening. This list is by no means exhaustive, and it will, hopefully, inspire the reader who observes under indifferent skies to take a fresh look at something not observed for years, or extend the hunt for more targets. They are there!

Fig. 8.2 Bob’s venerable Charles Frank 21-cm (8.5-in.) re fl ector

Fig. 8.3 The old 1980s lamps in my street threw a high percentage of their emissions skywards

Fig. 8.4 The day the new FCO lamp arrived opposite my observatory

135Andromeda (October)

Fig. 8.5 New metal halide lamp in my street – goes off at midnight

Andromeda (October)

(1) g Andromedae (Almach) R.A. 02 h 03 m Dec. +42° 20 ¢

A superb double star for any size of telescope. The primary (mag. 2.3) is golden yellow. The secondary (mag. 5.1), 9.8˜ distant , is often listed in handbooks as blue, but it remains resolutely green whenever I look at it. Is this just an idée fi xe , a con-trast effect, or a real color? Try a moderate magni fi cation. I see it well at ×108 (Fig. 8.8 ).

136 8 Targets

(2) NGC 752 R.A. 01 h 58 m Dec. +37° 41 ¢

A scattered cluster of stars, 15 of them above tenth magnitude, fi lling one square degree. The cluster contains a fi ne triple star and some pairs. NGC 752 is about 1,300 l.y. away. The apparently brightest member (mag. 7.1) may be a foreground object, not associated with the cluster. Best seen in binoculars or through a wide- fi eld, low-power eyepiece, using g And as a guide: NGC 752 is 5° south of the bright star. Do you see any reddish stars in the northern part of the cluster? (Fig. 8.9 ).

Fig. 8.6 The shields installed by the local council to protect my observing site are visible on this luminaire

137Aquarius (August–September)

Aquarius (August–September)

(3) S 2838 R.A. 21 h 55 m Dec. −03° 20 ¢

Halfway between a and b Aquarii, this easy double star, with its yellow primary (mag. 6.3) and bluish secondary (mag. 8.8), lies near what Victorian observer Reverend T. W. Webb called ‘a curious and beautiful stream of small stars north preceding.’ A small telescope at moderate power will split this pair, separation 16″. The reverend was right about the small stars.

Fig. 8.7 Better lighting, more stars: looking north from my back garden above two FCO streetlights

138 8 Targets

(4) t 1 Aquarii R.A. 22 h 48 m Dec. −14° 03 ¢

Primary mag. 5.8, secondary 9. This pair, 23.7″ apart and easily separated with a moderate power, is an optical double. Unremarkable colors, unlike nearby t 2 , a beautiful mag. 5 orange star with a faint blue line-of-sight companion preceding.

(5) Close by t 1 Aquarii, 4° to the northeast is a remarkable chain of mag. 8 stars containing the double star S 2970 (R.A. 23 h 02 m Dec. −11° 20 ¢ ; mags. 8.5, 9, sep. 8.5″). Low to moderate powers. Sweep around! (Fig. 8.10 )

Fig. 8.8 Gamma Andromedae is the bright star here beneath Comet C/1995 O1 (Hale-Bopp) on 1997 Mar 31. The comet’s tail sweeps towards the ‘W’ of Cassiopeia

139Aquarius (August–September)

Fig. 8.9 NGC 752Object: NGC 752 Instrument: 6-cm./2.5-in. refractor Constellation: Andromeda Magni fi cation: ×30Type: Open Cluster Field diameter: 45´Magnitude: 6 Seeing: Ant. IINumber of stars: 70+ Light pollution: moderate Norton’s 2000.0 chart: 3 Date: 1976 November 19 Uranometria 2000.0 chart: 92 Time: 2300 UT

Notes: Very large group, best in binoculars, with a fi ne bright triple and some interesting pairs

140 8 Targets

Aquila (July)

(6) 57 Aquilae ( S 2594) R.A. 19 h 54 m Dec. −08° 10 ¢

What color is the secondary star of this duo, easily split at ×40? Nineteenth-century observers, happy to record their subjective impressions, saw the mag. 6.2 compan-ion as ‘lilac’ (Webb), ‘pale blue’ (Knott), and ‘azure white’ (Dembowski). The yellow primary, mag. 5.2, is 36″ away.

(7) R Aquilae R.A. 19 h 06 m Dec. +08° 14 ¢

Many variable stars approach naked-eye visibility, but do not share the renown of those that, like Algol and Mira, have bright maxima. Long-period variable (LPV) R Aql is a fi ne red star, easily found with binoculars when at its maximum magni-tude of 5.5. Use Altair and z Aquilae to locate it (see chart). For how long can you follow it, as it dims towards its minimum of mag. 12? Its period of variability is 284

Fig. 8.10 t 1 Aqr to S 2970Object: S2970Constellation: Aquarius Type: Double starMagnitudes: 8.5, 9Separation: 8.5˜ Norton’s 2000.0 chart: 4 Uranometria 2000.0 chart: 303

141Aries (October–November)

days, a value that is slowly decreasing (a detailed examination by J. Greaves and J. Howarth of this star’s behavior appeared in the Journal of the British Astronomical Association , June 2000, pp. 131–142). Predictions for maxima/minima of many variable stars can be found in popular astronomy magazines such as Sky & Telescope or Astronomy Now , or websites such as that of the BAA Variable Star Section (Fig. 8.11 ).

Aries (October–November)

(8) 1 Arietis ( S 174) R.A. 01 h 50 m Dec. +22° 17 ¢

Nearly 2° north of Sheratan ( b Arietis), therefore easily found, and bright enough (mags. 6 and 7) for a small telescope. A fairly high magni fi cation (×100+) will reveal a fi ne golden-yellow and blue pair, 2.8″ apart.

(9) l Arietis (O S S 21) R.A. 01 h 58 m Dec. +23° 35 ¢

A fi ne wide double for a small telescope, mags. 4.9 and 7.7, sep. 38.5″. Is the primary white or blue? Easily found 2° west of a Ari (Hamal).

Fig. 8.11 Finding R AqlObject: R AquilaeType: Long-period variablePeriod: 284 days Norton’s 2000.0 chart: 13 Uranometria 2000.0 chart: 206

142 8 Targets

Auriga (December)

(10) NGC 1907 R.A. 05 H 28 m Dec. +35° 20 ¢

An interesting compact cluster, close to the galactic equator and half a degree south of the bright cluster M38, which serves as a signpost. 1907 bears high powers well, and many fainter cluster members suggest themselves at the limit of visibility. Averted vision can help bring out these tantalizingly faint stars, as it can with many of the items in this list. Averted vision is often more effective if the fi eld is allowed to drift and the eye concentrates on a fi xed point, rather than moving it to ‘hunt’ for the right distance from the object (Fig. 8.12 ).

(11) 14 Aurigae ( S 653) R.A. 05 h 15 m Dec. +32° 45 ¢

Centered in an interesting fi eld at ×50, the two components of 14 Aur show a marked color contrast: pale yellow and white (though I once recorded the secondary

Fig. 8.12 NGC 1907Object: NGC 1907 Instrument: 21-cm./8.5-in. re fl ector f/6Constellation: Auriga Magni fi cation: ×324Type: Open Cluster Field diameter: 8´Magnitude: 8 Seeing: Ant. IIINumber of stars: 40 Light pollution: moderate Norton’s 2000.0 chart: 5 Date: 1989 April 7 Uranometria 2000.0 chart: 97 Time: 2130 UT

Notes: Many stars of mags. 10+. ‘Haze’ of many members just below limit of visibility

143Boötes (April–May)

Fig. 8.13 Field of 14 Aur Object: 14 Aurigae Instrument: 21-cm./8.5-in. re fl ector f/6Type: Double star Magni fi cation: ×50Magnitudes: 5.1-5.2, 7.9 Field diameter: 45´Separation: 15˜ Seeing: Ant. III Norton’s 2000.0 chart: 5 Light pollution: moderate Uranometria 2000.0 chart: 97 Date: 1990 March 25 Time: 2229 UT

Notes: A fi ne colour contrast in a crowded fi eld

as ‘greenish’). The primary is slightly variable (KW Aur, described in Sky & Telescope December 1990, p. 610). Mags. 5.1–5.2, 7, sep. 15″. There is a faint mag. 11 companion 10″ to the north (Fig. 8.13 ).

Boötes (April–May)

(12 and 13) i and k Boötis R.A. 14 h 15 m Dec. +51° 30 ¢ (Center of Field)

This neat pair of pairs fi ts into a medium-power fi eld. You will need a fi eld diameter of at least 45 ¢ . All four stars look slightly different in hue – do you agree? Data: i , mags. 5.3, 7.5 (variable?), sep. 2.2″; k , mags. 4.6, 6.6, sep. 13.4″.

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Camelopardus (December)

(14) Kemble’s Cascade (The Wristwatch) R.A. 04 h Dec. +63°

I happened upon this fascinating binocular object quite by chance many years ago, and let out a whistle of disbelief. A wristwatch, or pendant necklace, opened out in the sky! Straddling four 50 ¢ telescope fi elds, this delicate chain of stars, seen in the photo (Fig. 8.14 ) in the same fi eld as Comet Hyakutake, nudges with its southern tip the dainty little telescopic cluster NGC 1502. Of all the many star chains and chance alignments in the sky, the Cascade must take the prize. See Sky & Telescope, December 1980, p. 547, for more information.

Fig. 8.14 ‘Kemble’s Cascade’ (‘The Wristwatch’) to the left of Comet C/1996 B2 (Hyakutake), 1996 March 30

145Camelopardus (December)

(15) Chain of pairs, Camelopardus/Cassiopeia R.A. 03 h 12 m to 32 m, Dec. +67° to +68°

The sketch (Fig. 8.15 ) shows, in three overlapping fi elds, a curious sequence of fi ve double stars, all mags. 7/8, straddling the Camelopardus-Cassiopeia border, inviting

Fig. 8.15 Chain of pairs in Camelopardus and CassiopeiaNorton’s 2000.0 chart: 2Uranometria 2000.0 chart: 18Instrument: 21-cm. /8.5-in. re fl ector f/6Magni fi cation: ×50Field diameter: 45´ (three fi elds)Ant. IILight pollution: moderateDate: 1990 October 12Time: 2250 UT

Notes: Some interesting sweeping around this chain of pairs

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some interesting exploring with both low and high powers. The pairs are: O S 54 Cam (mags. 7, 8.5, sep. 23.6″, p.a. 358°); S 374 Cam (mags. 7, 8.5, sep. 10.9″, p.a. 295°); Hu1056 Cam (mags. 8, 8, sep. 1″, p.a. 269°); SAO 12680/-81 Cas (my estimates: mags. 7, 9, sep. 25″, p.a. 175°); unidenti fi ed pair (Cas) (my estimates: mags. 8.5, 8.5, sep. 10″, p.a. 195°).

Cancer (January–February)

(16) 57 Cancri R.A. 08 h 54 m Dec. +30° 40 ¢

A ragged line of stars leads northeast from the colorful mag. 4 double star i Cancri towards 57, 2° away. This close pair (sep. 1.5″), mags. 6 (yellow) and 6.5 (yellow-orange), when closely examined, turns out to be a triple: an elusive ninth-mag. companion lies 50″ away to the south. Use high powers.

(17) M67 (NGC 2682) R.A. 08 h 50 m Dec. +11° 49 ¢

M67 is a good example of a ‘neglected neighbor,’ an object not much discussed and often forgotten about because it is upstaged by a showier target nearby: in this case, the ‘Beehive’ cluster, M44, 9° to the north.

Norton’s 2000.0 calls M67 ‘rich,’ though it is fairly compact at only 15 ¢ across. Of its 500 true members, none is brighter than mag. +10. A moderate telescope and low power will show a dozen stars in a straggling line, with a hint of many more just beyond the limit of visibility in a not too polluted sky (Fig. 8.16 ).

147Canes Venatici (April)

Fig. 8.16 M67Object: M67 (NGC 2682) Instrument: 6-cm./2.5-in. refractor Constellation: Cancer Magni fi cation: ×30Type: Open Cluster Field diameter: 45´Magnitude: 7 Seeing: Ant. IINumber of stars: 500+ Light pollution: moderate Norton’s 2000.0 chart: 7 Date: 1990 January 30 Uranometria 2000.0 chart: 187 Time: 2200 UT

Notes: Compact, with many faint stars at limit of visibility

Canes Venatici (April)

(18) Y Canum Venaticorum (‘La Superba’) R.A. 12 h 45 m Dec. +45° 26 ¢

Rightly called the ‘superb’ star by Secchi, Y CVn is not only a glorious red color, but also one of the brightest stars in this fairly dim constellation. Easily found, as it forms a right angle with a CVn and b CVn (Fig. 8.17 ), Y takes 157 days to fall from mag. 5.2 to mag. 6.6 and rise again. One of the most intriguing telescopic gems you can show a non-astronomer neighbor who thinks all stars are white is a relatively bright star of vivid red hue, such as Y CVn, R Lep (‘Hind’s Crimson Star’) or m Cep (‘The Garnet’). The diameter of Y CVn, a cool (~2,600°C) red giant, is about 400 million kilometers/250 million miles: if this star replaced the Sun, Earth’s orbit would lie about 50 million kilometers/30 million miles inside the star’s ‘surface.’

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(19) M3 (NGC 5272) R.A. 13 h 42 m Dec. +28° 23 ¢

You may not see this sixth-mag., slightly oval globular cluster quite as well as the Reverend Webb saw it in the better skies of the 1870s, ‘blazing into a confused brilliancy towards the center, with many outliers,’ but it is certainly a fi ne sight with moderate powers and a modest 10-cm/4-in. telescope. The outlying stars seem to form streams. This starry mass, 40,000 l.y. away, lacks the hint of darker patches seen in the central region of the better known globular M13. M3 contains about half a million stars in a spherical space about 220 l.y. across.

Canis Major (December–January)

(20) h3945 R.A. 7 h 17 m Dec. −23° 18 ¢

Why doesn’t Norton’s 2000.0 describe in its listings h3945 (or 145 CMa), which shows the fi nest color contrast of any double star in the winter sky? Look for this pair, orange-red and electric blue, just east of o 2 CMa and north of t . Finding it by

Fig. 8.17 Finder chart for Y Canum VenaticorumObject: Y Canum Venaticorum (‘La Superba’)Type: Semi-regular variablePeriod: ~160 days Norton’s 2000.0 chart: 9 Uranometria 2000.0 chart: 75

149Canis Major (December–January)

chance for the fi rst time in 1971, low in the south through the light pollution of Poole, I was amazed that I had never heard of this celestial gem before. A must! Mags. 4.8, 6; separation 27″, easily split with moderate power. This is an optical double, only a line-of-sight effect; the brighter of the two stars is 2,500 l.y. from us, while its ‘neighbor’ is only one-tenth of that distance away. The fi nder chart (Fig. 8.18 ) does not include all the stars in this rich area (h3945 is just within the traditional Milky Way ‘boundary’) and is meant for ‘star-hopping’ using d and t as pointers.

(21) W Canis Majoris R.A. 07 h 08 m Dec. −11° 55 ¢

A slow, irregular variable, close to the galactic equator and worth watching. Its maximum magnitude (6.35) makes it an easy binocular object. One of the N-spectrum ‘carbon stars,’ characteristically red. Minimum mag. 7.9.

Fig. 8.18 A ‘star-hop’ to h3945Object: h3945Constellation: Canis MajorType: Double starMagnitudes: 4.8, 7Separation: 27˜ Norton’s 2000.0 chart: 8 Uranometria 2000.0 chart: 319

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Canis Minor (January–February)

(22) S 1149 R.A. 07 h 49 m Dec. +03° 12 ¢

A double star, low in the winter sky for northern observers, but well worth the hunt. At the western end of a line of mag. 6 and 7 stars, some themselves double, strung out just south-east of Procyon, this pair is yellow and blue, mags. 7.5 and 9, 22″ apart, position angle 41°. A medium power on a small instrument, e.g., 7.5-cm/3-in., will split it.

(23) More of a challenge at the other end of the line of stars indicating S 1149 is O S 182, a brighter pair (7, 7.5), but only 1″ apart. Highest power needed (Fig. 8.19 )

Fig. 8.19 Stars near S 1149Object: S1149 Instrument: 21-cm./8.5-in. re fl ector f/6Constellation: Canis Minor Magni fi cation: ×32Type: Double star Field diameter: ~1°Magnitudes: 7.5, 9 Seeing: Ant. IISeparation: 22˜ Light pollution: moderate Norton’s 2000.0 chart: 7 Date: 1989 April 2 Uranometria 2000.0 chart: 230 Time: 2030 UT

Notes: Striking ‘snake’ of four main fi eld stars

151Cassiopeia (October)

Capricornus (August)

Down in the worst of the light pollution for many observers, Capricornus still offers some interest.

(24) a Capricorni R.A. 20 h 17 m Dec. −12° 30 ¢

Algiedi (‘The Goat’) is a wide naked-eye pair, 380″ apart, and splendid in a low-power fi eld. In reality, however, a 1 (700 l.y.) is more than six times further from us than a 2 (108 l.y.), the more southerly and brighter of the two. a 1 , mag. 4.5, has a dif fi cult ninth-mag. companion 45″ away, while a 2 , mag. 3.5, is also double, the companion being of mag. 11 at 6.6″.

Cassiopeia (October)

High above in autumn, in what is often the least polluted part of the sky, Cassiopeia is rich in worthwhile objects.

(25) O S S 254 (Primary is WZ Cassiopeiae) R.A. 00 h 02 m Dec. +60° 25 ¢

A fi ne wide double with good color contrast. Deep orange-red (mag. 7) and striking blue (mag. 8), well seen with a medium-sized re fl ector (15–21 cm/6–8 in.) at about ×100. Separation 58″. In a crowded fi eld (Fig. 8.20 ), and the colors are superb when the red semi-regular variable WZ is at its brightest (magnitude range 7–10, period 186 days).

(26) NGC 457 R.A. 01 h 19 m Dec. +58° 20 ¢

One of the most pleasingly arranged clusters in the sky, and easily seen even with low power (e.g. ×32) and a modest telescope. Highly luminous supergiant f Cas (mag. 5) is involved, making it easy to fi nd. My daughter, seeing it for the fi rst time, exclaimed: ‘It’s a little stick-man with two big, bright eyes!’ With south upwards, as shown by the chart (Fig. 8.21 ), the cruciform cluster suggests just this at low

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Fig. 8.20 Field of WZ CasObject: OSS254 primary is WZ Cas) Instrument: 21-cm./8.5-in. re fl ector f/6Constellation: Cassiopeia Magni fi cation: ×108Type: Double star Field diameter: 21´Magnitudes: 7, 8 Seeing: Ant. ISeparation: 58˜ Light pollution: moderate Norton’s 2000.0 chart: 2 Date: 1990 September 17 Uranometria 2000.0 chart: 35 Time: 2215 UT

Notes: Colours very striking: deep orange-red, electric blue

powers. Sometimes called the ‘Owl’ cluster (which may lead to some confusion with planetary nebula M97, the Owl Nebula), but the stick-man can’t be ignored. Distance about 8,000 l.y. Recent Hipparcos measurements suggest that the two ‘eyes,’ f Cas and HD7902, are foreground stars, between 2,000 and 3,000 l.y. away.

(27) Trumpler 1 R.A. 01 h 36 m Dec. +61° 18 ¢

Between two of Cassiopeia’s showpiece clusters, M103 and NGC 663, is a modest little group of about 25 stars, the brightest of them about mag. 10. What makes Tr 1 worth a look at high powers (×100+) is the remarkable north-south line-up of the four main stars, an intriguing sight at ×323. Easily found by moving ahead of NGC 663 in R.A.

153Cepheus (August–September)

Cepheus (August–September)

(28, 29, 30) An interesting fi nd: three multiple stars in the same ×50 fi eld (diameter 45 ¢ ), in a crowded area. Try centering your instrument on:

S 2816, at R.A. 21 h 39 m, Dec. +57° 30 ¢ . The chart (Fig. 8.22 ) shows three members of this quadruple system, with S 2813

and S 2819 bracketing it. Data:

S 2813: mags. 8.5, 9, sep. 10″; S 2816: mags. 6.3, 7.9, 8, 13, seps. 11″, 20″, 1.6″; S 2819: mags. 7.5, 8.5, sep. 12″.

Fig. 8.21 NGC 457Object: NGC 457 Instrument: 21-cm./8.5-in. re fl ector f/6Constellation: Cassiopeia Magni fi cation: ×32, ×108Type: Open Cluster Field diameter: 50´Magnitude: 6.5 Seeing: Ant. INumber of stars: ~100 Light pollution: slight Norton’s 2000.0 chart: 2 Date: 2000 July 29 Uranometria 2000.0 chart: 36 Time: 2229 UT

Notes: Grand, cruciform group. f yellow, fi ne contrast with blue neighbour mag. 7 and V465 ( red )

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(31) RW Cephei R.A. 22 h 23 m Dec. +55° 58 ¢

Not a bright star, this irregular variable, but if you can catch it near the top of its range (mag. 7.6, falling to 9), do you see it as pink? Use e Cep as a starting point for your ‘star-hop’ towards RW’s location by the border with Lacerta: stars down to mag. 8 are shown only for the preceding side of the chart (Fig. 8.23 ).

(32) NGC 6939 R.A. 20 h 31 m Dec. +60° 40 ¢

(33) NGC 6946 R.A. 20 h 35 m Dec. +60° 09 ¢

The old cliché ‘stardust’ comes to mind as open cluster 6939 slides into a medium-power fi eld. A mass of fairly faint stars packs its center, and averted vision suggests

Fig. 8.22 S 2813, S 2816, S 2819Objects: S2813/2816/2819 Instrument: 21-cm./8.5-in. re fl ector f/6Constellation: Cepheus Magni fi cation: ×50Type: Double stars Field diameter: 45´Magnitudes: see text Seeing: Ant. II-IIISeparation: see text Light pollution: moderate Norton’s 2000.0 chart: 2 Date: 1991 August 14 Uranometria 2000.0 chart: 57 Time: 2330 UT

Notes: Three intriguing pairs chase slowly across a superb fi eld

155Cepheus (August–September)

many more, frustratingly at the limit of perception. Sc galaxy 6946, resembling a shrunken M33 in photographs, and exactly straddling the Cepheus-Cygnus border, appears as a small, ghostly, fl eetingly glimpsed disc in the same fi eld as 6939 at ×50. There is a splendid photo showing both objects in Burnham’s Celestial Handbook , p. 620. The galaxy is also noteworthy for relatively frequent discoveries of supernovae (1917, 1939, 1948, 1968, 1969, 1980), which is probably related to the fact that it is only about 15 million l.y. from the Milky Way. Worth a frequent look, therefore.

(34) NGC 7538 R.A. 23 h 14 m Dec. +61° 30 ¢

A superb color photo of this complex of nebulae on the Cepheus-Cassiopeia border appeared on the cover of Sky & Telescope in August 1991 (though it was wrongly assigned to Perseus). I looked for it that same month, on a very clear and still night, at ×108, and was delighted to see not only a hint of the three main areas of nebulos-ity but some internal brightness gradation. I have never found it again. De fi nitely a challenge for the most transparent nights!

Fig. 8.23 A ‘star-hop’ to RW CepObject: RW CepheiType: Irregular variable Norton’s 2000.0 chart: 2 Uranometria 2000.0 chart: 57

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Cetus (October–November)

Though low in the sky for observers in northern mid-latitudes, Cetus offers:

(35, 36) 37 Ceti and S 101. R.A. 01 h 14 m Dec. −7° 55 ¢ (37 Cet)

In the same low-power fi eld, this pair of pairs is a striking sight, if challenging because of their low declination, with possible strong light pollution. Data: 37 Cet: mags. 5, 7, sep. 50″; S 101: mags. 8, 10, sep. 21″, located just west of J Ceti (mag. 3.8). Webb described both pairs as ‘yellow and orange.’

Coma Berenices (March–April)

(37) Melotte 111 R.A. 12 h 24 m Dec. +26° (Center of Field)

To the unaided eye, the constellation of Berenice’s Hair is a vague and inconspicu-ous scattering of sub-fourth magnitude stars. Several of its brightest members belong to the nearby galactic cluster Melotte 111, about 250 l.y. distant. Tainted skies may not allow you to share G. P. Serviss’ poetic impression of this group (‘gossamer spangled with dewdrops’), but try Mel 111 with low-power binoculars when it is high.

(38) S 1639 R.A. 12 h 24 m Dec. +25° 35 ¢

Try a high power on this one: at ×323, I opened up the 1.3″ gap between these two pale yellow stars, mags. 6.6, 7.8. In the middle of Mel 111 (see above), and 1° preceding and slightly south of the wide double 17 Com.

Corona Borealis (May)

(39) T Coronae Borealis R.A. 15 h 59 m Dec. +25° 55 ¢

This one is for optimists only! Keep a regular binocular watch on the area just below the little Crown (Fig. 8.24 ), where lurks a recurrent nova: T CrB, the ‘Blaze Star,’ a variable star normally at mag. 10.3, which might just have a surprise in store. The larger component of T CrB is thought to be a stable red giant, with a

157Cygnus (July–August)

Fig. 8.24 Finder chart for T CBrObject: T Coronae BorealisType: Recurrent nova Norton’s 2000.0 chart: 11 Uranometria 2000.0 chart: 155

smaller blue companion which exhibits unpredictable fl uctuations due to material falling upon it from its bloated neighbor. A fi erce 1866 outburst reached mag. 2. Some 80 years later, in February 1946, T CrB brightened to mag. 3, its outer layers bursting away at an estimated 2,700 miles (4,320 km) per second, according to Burnham. Another 80 years would take us to 2026, but we may not have to wait until then for another paroxysm: John Herschel noted a brightening in 1842 to mag. 6, just 24 years before T CrB’s 1866 display.

(40) z Coronae Borealis R.A. 15 h 39 m Dec. +36° 38 ¢

An easy double (mags. 5, 6, sep. 6.3″) for a small telescope and moderate power. A beautiful white-white pair. Webb calls the stars ‘greenish.’

Cygnus (July–August)

(41) 61 Cygni R.A. 21 h 07 m Dec. +38° 45 ¢

See the galaxy rotate! Well, not quite, but 61 Cyg (‘Piazzi’s Flying Star’) is a binary star whose motions you can measure and record over the years with a small tele-scope. The two components, mags. 5.3 and 5.9, both orange, perform a slow 700-year orbital dance, but of more interest is the abnormally rapid annual proper

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motion of 5.22″ north-eastwards against the background stars, due to 61 Cyg ‘passing’ the Sun at a distance of only 11 l.y. The sketch (Fig. 8.25 ) shows my observations of its positions in 1970 with open circles, and in 1992 as fi lled circles. Where do you see it now?

(42) Region of SAO 50246 R.A. 20 h 55 m Dec. +47° 25 ¢

This unremarkable sixth-magnitude star is preceded by a marvelous fi eld of fainter stars in curious chains and swirls (Fig. 8.26 ). Low power and a wide fi eld reveal the whole grand sight. Uranometria 2000.0 shows nebula I.5076 around the star. I see no sign of it, but can the star chains be related?

Fig. 8.25 Motion of 61 Cyg: positions in 1970 and 1992Object: 61 Cygni Instrument: 21-cm./8.5-in. re fl ector f/6 Magni fi cation: ×108Type: Double star Field diameter: 21´Magnitudes: 5.3, 5.9 Seeing: Ant. IISeparation: 30˜ Light pollution: moderate Norton’s 2000.0 chart: 13 Date: 1970 July 10, 1992 July 31 Uranometria 2000.0 chart: 121 Time: 2300 UT, 2318 UT

Notes: Orange pair in a fairly crowded fi eld

159Delphinus (July–August)

(43) NGC 6866 R.A. 20 h 04 m Dec. +44° 10 ¢

A large and beautiful open cluster, with many faint stars in branching lines, suggesting open wings. About 40 stars seen at ×79. Find 6866 by moving 1° south of d Cyg (R.A. 19 h 45 m), and then 19 min in increasing R.A. (or nearly 5°) to 20 h 04 m.

Delphinus (July–August)

(44) NGC 7006 R.A. 21 h 02 m Dec. +16° 11 ¢

Not a hard one to pinpoint, but a faint one! If you put g Delphini, the Dolphin’s ‘nose,’ at the center of a medium-power fi eld (say, ×108), and sweep slowly east-

Fig. 8.26 Star chains near SAO 50246Objects: Field of SAO 50246 Instrument: 21-cm./8.5-in. re fl ector f/6Constellation: Cygnus Magni fi cation: ×50 Norton’s 2000.0 chart: 13 Field diameter: 45´ Uranometria 2000.0 chart: 85 Seeing: Ant. II Light pollution: moderate Date: 1992 July 28 Time: 2255 UT

Notes: Splendid lanes of faint stars. Not listed as a cluster

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wards for nearly 4°, you might just catch a glimpse of NGC 7006, the globular cluster which holds the record as the furthest such object from us in the Milky Way’s halo, at 130,000 l.y. (Burnham) – if you don’t include the extra-galactic ‘wanderer’ NGC 2419 in Lynx, (~250,000 l.y), described below. NGC 7006 is elusive at mag. 11; I think I once saw it fl eetingly as a faint smudge, with averted vision, through the 21-cm/8.5-in. re fl ector at ×216 (×108 with ×2 Barlow).

(45) NGC 6934 R.A. 20 h 34 m Dec. +07° 20 ¢

No luck with 7006? Console yourself with this small but brighter globular, mag. 9, 4° almost due south of the Dolphin’s ‘tail’ star, e Delphini. It looks like a slightly out-of-focus star at ×108. Bluish?

Draco (March–June)

(46) S 2398 R.A. 18 h 43 m Dec. +59° 45 ¢

A binary with extremely rapid proper motion (2.3″ per year), being only 11.3 l.y. away. At intervals of just a few years, you can track its path across the sky against background stars. The sketch (Fig. 8.27 ) shows its position in 1967 (cf. Burnham’s Celestial Handbook , p. 869) with open circles, and my observation of its changed position in 1989 as fi lled circles. Not shown in Norton’s 2000.0 , but easily found 1° preceding 47 (Omicron) Dra. Mags. 8, 8.5, sep. 15.3″, position angle 163°, both red dwarfs. Easy with low power.

(47) 5, 6 Draconis and SAO 7611 R.A. 12 h 36 m Dec. +70° (Center of Field)

A bright trio, mags. 4, 5 and 7, easily seen in binoculars. Aim a telescope at them, with a low power for a wider fi eld, and admire the colors. I see them as, respec-tively, blue-white, orange and yellow. There is a curious echo of this set of stars 2° away to the north: a fainter trio (mags. 8, 8, 9) in the same pattern and orientation.

161Draco (March–June)

Fig. 8.27 Motion of S 2398 against background stars: positions in 1967 and 1989Object: S2398 Instrument: 21-cm./8.5-in. re fl ector f/6Constellation: Draco Magni fi cation: ×100Type: Double star Field diameter: 25´Magnitudes: 8, 8.5 Seeing: Ant. II-IIISeparation: 15˜ Light pollution: moderate Norton’s 2000.0 chart: 2 (1° p. 47 Dra) Date: 1989 June 18 Uranometria 2000.0 chart: 54 Time: 2334 UT

Notes: Motion in 22 years approximately 50˜

(48) Field of Stars Centered on R.A. 18 h 35 m Dec. +72° 25 ¢

A miniature mirror-image of the main stars of Cassiopeia! A pleasingly symmetri-cal group of mag. 6 to mag. 8 stars half a degree across, but I can’t fi nd them listed as a cluster. Low power best (Fig. 8.28 ).

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Gemini (December–January)

(49) a Geminorum (Castor) R.A. 07 h 35 Dec. +31° 53 ¢

Not hard to fi nd! This famous sextuplet system consists of three pairs, Castor A, B and C, 52 l.y. away.

Castor A: mag. 1.9; Castor B: mag. 2.9, A-B sep. 3.9″; Castor C [YY Gem], variable, mag. 8.9–9.6, 70″ away to the south. It was the rapid 400-year orbit of Castor B around Castor A that fi nally con-

vinced William Herschel of the reality of binary systems. Webb saw A as ‘greenish.’ Try highest magni fi cations.

Fig. 8.28 A miniature Cassiopeia in DracoObjects: Star fi eld centred on R.A. 18h 35m, Dec. +72° 25´Constellation: Draco Instrument: 21-cm./8.5-in. re fl ector f/6Magnitudes: 6-8 Magni fi cation: ×50 Norton’s 2000.0 chart: not shown Field diameter: 45´ Uranometria 2000.0 chart: 12 Seeing: Ant. III Light pollution: moderate Date: 1989 June 20 Time: 2329 UT

Notes: A pleasingly balanced group, immediately suggesting a mirror image of Cassiopeia

163Lacerta (September)

(50) d Geminorum (Wasat) R.A. 07 h 20 m Dec. +21° 59 ¢

Although d is in itself interesting, being a fi ne binary (mags. 3.5, 8.2; sep. 5.8″) through a high-power eyepiece, aim your telescope just 1° ESE of it, at a point halfway between d and another binary, 63 Gem (R.A. 07 h 27 m, Dec. +21° 27 ¢ ). Nothing there? Not much, but it’s a historic sky location. In January 1930, Pluto’s faint image occupied this spot on a photographic plate taken at Flagstaff Observatory by Clyde Tombaugh. Since that time, Pluto has completed little more than one-third of its unconventional 249-year orbit around the Sun, and at the time of writing (September 2011) it lies in Sagittarius, more than 10° above the ecliptic.

Hercules (May–June)

(51) M92 (NGC 6341) R.A. 17 h 17 m Dec. +43° 08 ¢

This fi ne globular cluster, about 30,000 l.y. away, is very much a ‘neglected neigh-bor,’ outclassed by M13, 9° to the SW. M92 is easy to fi nd at mag. 6.1. Discovered not by Messier but by Bode in 1777, it is well worth a look, through any telescope. Do you see M92 as slightly oval?

(52) NGC 6210 ( S 5) R.A. 16 h 45 m Dec. +23° 49 ¢

This mag. 9 planetary nebula, about 5,000 l.y. away, is surprisingly bright. It looks like a slightly defocused star at high powers. Burnham has it as ‘bluish,’ and the Earl of Rosse listed it as ‘intense blue.’ I can’t agree with these worthies as to the color, but it’s a rewarding target for small telescopes. The line from g Her through b Her will take you to 6210, about 4° northwest of b . There is a double and a triple star in the low-power fi eld of 6210: S 2087 (mags. 8, 8, sep. 6″ ) to the west, and S 2094 (mags. 7, 8, 11, seps. 1.1″ and 25″) to the SSW.

Lacerta (September)

This small, unsung constellation deserves a better press. Its position within the Milky Way guarantees many intriguing clusters and fi ne star fi elds.

(53) NGC 7209 R.A. 22 h 05 m Dec. +46° 30 ¢

On fi rst seeing this delicate cluster at ×108, I thought its ragged curves and clumps of stars suggested the outline of a maple leaf (Fig. 8.29 ). Distance about 3,000 l.y.

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(54) NGC 7296 R.A. 22 h 28 m Dec. +52° 15 ¢

A much tighter cluster than 7209, and closely following b Lac, which looks orange. The cluster has one dominant star (mag. ~9), which seems to be ‘sowing’ several fainter members behind it as it moves across the fi eld. Webb described the star fi elds of this area, with their chains, curves and pairs of faint stars, as ‘glorious,’ and they certainly repay sweeping with low and medium powers.

Fig. 8.29 NGC 7209Object: NGC 7209 Instrument: 21-cm./8.5-in. re fl ector f/6Constellation: Lacerta Magni fi cation: ×108Type: Open Cluster Field diameter: 21´Magnitude: 7 Seeing: Ant. IIINumber of stars: ~50 Light pollution: moderate Norton’s 2000.0 chart: 13 Date: 1994 September 1 Uranometria 2000.0 chart: 87 Time: 2244 UT

Notes: Quite large, ragged cluster. Curves and ‘points’ suggest maple leaf

165Leo (February–March)

Leo (February–March)

(55, 56) 3 Leonis R.A. 09 h 28 m Dec. +08° 10 ¢ and 6 Leonis R.A. 09 h 32 m Dec. +09° 45 ¢

Two very similar, fairly wide double stars less than 2° apart. Intriguingly, 3 and 6 echo each other in orientation (p.a. 80°, 75°), magnitudes (6, 10; 6, 9) and colors (both yel-low-orange and dull blue-grey). Separations 25″, 37″. Between them lies another dou-ble, w (2) Leonis, much harder to split (mags. 6, 7; sep. 0.4″). High powers needed.

(57) NGC 2903 R.A. 09 h 32 m Dec. +21° 30 ¢

Leo contains some galaxies bright enough to show through moderate light pollution, and M65, M66 and M96 (all mag. 9) and M95 (mag. 10) are well known to many observers. Leo has many other galaxies attainable with medium to high powers in very clear skies: just in front of the Lion’s ‘nose,’ search for the Sc system NGC 2903, a mag. 9.7 smudge with a comparatively bright nucleus (Fig. 8.30 ).

Fig. 8.30 NGC 2903Object: NGC 2903 Instrument: 21-cm./8.5-in. re fl ector f/6Constellation: Leo Magni fi cation: ×108Type: Galaxy Sc Field diameter: 21´Magnitude: 9 Seeing: Ant. II Norton’s 2000.0 chart: 7 Light pollution: moderate Uranometria 2000.0 chart: 143 Date: 1992 March 9 Time: 0018 UT

Notes: Bright centre and neat oval form, with hint of arm to south

166 8 Targets

Leo Minor (February–March)

A small, neglected constellation with some interesting double stars.

(58) S 1374 R.A. 09 h 41 m Dec. +38° 56 ¢

A binary with fi ne colors (mag. 7, yellow, and mag. 8, blue), though close (3.2″). Well seen at ×323.

(59) NGC 3245 R.A. 10 h 27 m Dec. +28° 33 ¢

Probably Leo Minor’s best galaxy, mag. 11, rather elongated with a starlike nucleus at ×108. Why did D’Arrest call it ‘oblong’? One way to ‘ fi sh up’ this galaxy is to center g Leonis, in the ‘mane’ of the larger lion, in a telescope fi eld, then move 9° northwards and 2° eastwards.

Lynx (January–February)

Devoid of bright stars, Lynx has one or two surprises awaiting the dogged observer.

(60) NGC 2419 R.A. 07 h 38 m Dec. +38° 53 ¢

You would think that this globular cluster, so far away (~250,000 l.y.) that it is considered an ‘extragalactic wanderer,’ would be an impossible object, yet I saw it with averted vision from my suburban garden at ×108 on a very clear, still night even before those ‘sky-friendly’ lights appeared in the street. There is a very slight hint of central brightening. Burnham gives its magnitude as 11.5, but it is easier to see than NGC 7006, another distant globular of the same estimated magnitude in Delphinus. Two mag. 8 stars, one of them double, point to its position closely fol-lowing them in R.A. These stars are easy to fi nd, as they are exactly 7° north of Castor and a little east.

167Lynx (January–February)

(61) NGC 2683 R.A. 08 h 54 m Dec. +33° 30 ¢

On a freezing night in December 1995, with the air temperature down to −8°C (17°F) and the sky remarkably clear, I found this broad spindle of a galaxy. It showed some detail at ×108, its southern end appearing slightly brighter than its northern end (Fig. 8.31 ). At mag. 10, its apparent size is 9 ¢ × 1.3 ¢ in a large telescope ( Burnham ). It lies about 20 million l.y. away.

(62) 19 Lyncis ( S 1062) R.A. 07 h 23 m Dec. +55° 17 ¢

Fairly bright and wide (mags. 5.5, 6.5, sep. 15″), this pair has an 11th-magnitude companion at 74″, p.a. 287° (i.e., preceding).

Fig. 8.31 NGC 2683Object: NGC 2683 Instrument: 21-cm./8.5-in. re fl ector f/6Constellation: Lynx Magni fi cation: ×108Type: Galaxy Sb Field diameter: 21´Magnitude: 10 Seeing: Ant. I Norton’s 2000.0 chart: 7 Light pollution: moderate Uranometria 2000.0 chart: 102 Date: 1995 December 26 Time: 0018 UT

Notes: A broad spindle, no bright nucleus, faint star at northern end. Temperature at observatory −8°C, air very still

168 8 Targets

Lyra (June–July)

(63) a Lyrae (Vega) R.A. 18 h 37 m Dec. 38° 78 ¢

According to Burnham, the fi rst star to be photographed, from Harvard in 1850. The bluish optical companion (mag. 10, distance just over 1 ¢ ) is almost lost in the glare of Vega (mag. 0.0). Glimpse it at highest powers through a 21-cm/8-in. instru-ment, though darker skies seem paradoxically to conceal it.

(64) T Lyrae R.A. 18 h 32 m Dec. +37° 00 ¢

This blood-red jewel, when at its brightest (mag. 7.5–9.3, irregular), is a stunning object in a well-populated fi eld. Do you agree that a fairly low power (say, ×50) seems to show off the color best? Try sweeping slowly for T Lyr in the area 2° southwest of a (Vega), and let its color signal its identity, or ‘star-hop’ to the vari-able using the chart (Fig. 8.32 ), which shows stars (to mag. 9) in the fi eld between Vega and T Lyr.

Fig. 8.32 From Vega to T LyrObject: T LyraeType: Irregular variable Norton’s 2000.0 chart: not shown Uranometria 2000.0 chart: 117

169Ophiuchus (May–June)

Ophiuchus (May–June)

(65) IC 4665 R.A. 17 h 46 m Dec. +05° 43 ¢

A fi ne cluster for binoculars or a wide- fi eld eyepiece, IC 4665 is wider than the full Moon, and easily found by panning 1.5° northeast from nearby b Oph. Alan MacRobert pointed out ( Sky & Telescope , June 1989, p. 605), that the pattern of the main stars forms the word ‘HI’ when southwest is up (Fig. 8.33 ). Perhaps a good object to ‘break the ice’ when showing your fl oodlight-dependent neighbor, at the telescope, why you’d like the sky to be darker? IC 4665 is about 1,000 l.y. away.

(66) NGC 6633 R.A. 18 h 28 m Dec. +06° 34 ¢

This compact curve of stars, of mags. 8 and below, became brie fl y the astrophotog-raphers’ favorite target on November 14, 1987, when the nucleus of Comet 1987s (Brad fi eld) passed right in front of it. The chart (Fig. 8.34 ) records the event as seen

Fig. 8.33 IC 4665, the ‘HI!’ clusterObject: IC 4665 Instrument: 21-cm./8.5-in. re fl ector f/6Constellation: Ophiuchus Magni fi cation: ×50Type: Open Cluster Field diameter: 45´Magnitude: 4.5 Seeing: Ant. IINumber of stars: 20 Light pollution: moderate Norton’s 2000.0 chart: 11 Date: 1996 July 23 Uranometria 2000.0 chart: 203 Time: 2300 UT

Notes: A grid pattern of bright stars in a very large cluster

170 8 Targets

in a slightly hazy sky, at 18.48 UT, through a small 6-cm/2.5-in. refractor at ×30. Even without such distinguished company, 6633 is still worth a look, through big (×20) binoculars or a low-power eyepiece. About 1,000 l.y. away.

Orion (December–January)

(67) s Orionis R.A. 05 h 39 m Dec. −02° 36 ¢

A splendid multiple system. Easy to fi nd, 1° southwest of z Ori, the left-hand ‘belt’ star. You can see fi ve components (mags. 4, 6, 6.5, 7.5, 10) at ×108, with the triple S 761/761b close by to the northeast. s Ori is 1,400 l.y. away.

Fig. 8.34 NGC 6633 and Comet 1987S (Brad fi eld)Object: NGC 6633 Instrument: 6-cm./2.5-in. refractor Constellation: Ophiuchus Magni fi cation: ×30Type: Open Cluster Field diameter: 45´Magnitude: 5 Seeing: Ant. IIINumber of stars: ~65 Light pollution: moderate Norton’s 2000.0 chart: 13 Date: 1987 November 14 Uranometria 2000.0 chart: 205 Time: 1848 UT

Notes: A superb sight. Estimated magnitude of comet 5.5

171Pegasus (September–October)

(68) 14 (O S 98) Orionis R.A. 05 h 08 m Dec. +08° 30 ¢

This close binary, sep. 0.8″, looks unremarkable: with highest power, two fairly similar white stars (mags. 6, 6.5) can be seen, with a delicate little double ( S 643) close by to the south. But sketch 14 Ori over the years, and watch the position angle change. Its 160-year period means that, in the decade 2010–2020, the secondary will appear to move through more than 20° in its orbit around the primary. More information, and chart, in Karkoschka (see Bibliography ).

Pegasus (September–October)

(69) NGC 7331 R.A. 22 h 37 m Dec. +34° 25 ¢

At mag. 9.7, the brightest member of a whole fi eld of galaxies to the north of h Peg, this almost edge-on Sc spiral (some authorities classify it as Sb) appears slightly asymmetrical in two ways: the obvious nucleus a little off center, and the ‘spindle’ appearing brighter along its southern ‘spike’ (at ×108). Do you agree? Astronomers often propose 7331 as an example of what our Milky Way Galaxy might look like from a viewpoint in deep space. Don’t expect to see its very faint neighbors with modest instruments! Distance about 55 million l.y. (Fig. 8.35 ).

(70) 3 Pegasi R.A. 21 h 38 m Dec. +06° 37 ¢

A glittering fi eld, 3° south and nearly 2° west of e Peg: 3 Peg (mags. 6, 8.5, sep. 39″, and there is a third, mag. 13 member) is attended to the northeast by fainter O S 443 (8, 8.5, 8″). Other nearby stars combine to give the impression of a sparse cluster. Medium power.

http://dx.doi.org/10.1007/978-1-4614-3822-9_BM1

172 8 Targets

Perseus (November–December)

Perseus’ crowds of stars offer countless targets, both famous and obscure, even in poor skies. Have you ever come upon these three?

(71) S 297 R.A. 02 h 46 m Dec. +56° 30 ¢

A pretty triple star, in a crowded fi eld, colors (blue-white, blue-white, yellow) well seen at ×108. Mags. 8, 8.5, 10.5. One degree away, south preceding, is Trumpler 2, a delicate cluster. To fi nd this triple, just savor the delights of the Perseus Double Cluster (NGC 869/884), then move half a degree to the south, and S 297 follows closely in R.A.

Fig. 8.35 NGC 7331Object: NGC 7331 Instrument: 21-cm./8.5-in. re fl ector f/6Constellation: Pegasus Magni fi cation: ×108Type: Galaxy Sc Field diameter: 21´Magnitude: 10 Seeing: Ant. II-III Norton’s 2000.0 chart: 3 Light pollution: moderate Uranometria 2000.0 chart: 123 Date: 1988 November 12 Time: 2155 UT

Notes: Slightly asymmetrical, more visible to south. Nearby fainter galaxies not seen

173Perseus (November–December)

(72) NGC 1582 R.A. 04 h 33 m Dec. +43° 50 ¢

It’s easy to fi nd this large cluster, nearly zenithal at Christmastime, 7° preceding the giant star e Aurigae. Its brightest members form a straggly ‘S,’ snaking across the ¾° fi eld of my ×50 eyepiece. There is some rewarding sweeping, with many pairs and curious star alignments, both north and south of the cluster.

(73) Stock 4 R.A. 01 h 53 m Dec. +57°

St 4 is a grand sight at ×50. Not listed in most handbooks and atlases, this large, loose group lies neglected in the northeast corner of Perseus. Half the 45 ¢ low-power fi eld (Fig. 8.36 ) is strewn with faint stars, and my fi rst impression of it through the telescope on a clear, frosty autumn night, was: ‘like a rain of tiny ice crystals.’ Easily found, as its declination is the same as that of the Double Cluster, which it precedes by 7° (28 min in R.A.).

Fig. 8.36 St 4Object: Stock 4 Instrument: 21-cm./8.5-in. re fl ector f/6Constellation: Perseus Magni fi cation: ×50, ×108Type: Open Cluster Field diameter: 45´Magnitude: 7 Seeing: Ant. IINumber of stars: 100+ Light pollution: moderate Norton’s 2000.0 chart: not shown Date: 1991 December 4 Uranometria 2000.0 chart: 37 Time: 2234 UT

Notes: A mass of faint stars

174 8 Targets

Pisces (September–October)

(74) y 1 Piscium ( S 88) R.A. 01 h 06 m Dec. +21° 30 ¢

Superb white-white twins, both mag. 5, and 39″ apart. A very easy object at what-ever power.

Sagitta (July–August)

The little Arrow’s position in the Milky Way guarantees plenty of interest packed into only 80 square degrees – only one northern constellation is smaller: Equuleus, the Foal, at 72 square degrees.

(75) U Sagittae R.A. 19 h 18 m Dec. +19° 37 ¢

The eclipsing binary Algol ( b Per) has a serious if shy rival here. Follow the varia-tions of U Sge, an easy binocular object, by comparing it with S 2504 (mag. 6.5), half a degree to the southeast. The fi eld is easy to fi nd, just west of the ‘hook’ of the well-known ‘Coat hanger’ asterism Collinder 399 in Vulpecula (Fig. 8.37 ).

Fig. 8.37 Finder chart for U SgeObject: U SagittaeType: Eclipsing binaryPeriod: 3.381 days Norton’s 2000.0 chart: 13 Uranometria 2000.0 chart: 161

175Sagitta (July–August)

At maximum, U Sge (mag. 6.4) is a little brighter than S 2504. Every 81.14 h (3.381 days), it will dim rapidly towards a minimum of mag. 9.2, where it remains for 1 h 40 m. The brighter, blue B8-type component is completely hidden at each eclipse by its faint, Sun-like G2 companion; Algol’s ‘eclipse’ is only partial, with about 80% of the brighter star hidden by its large neighbor.

(76) Field of 13 Sagittae R.A. 20 h 00 m Dec. +17° 30 ¢ (mags. 6, 12; sep. 28″)

(77) Field of 15 Sagittae R.A. 20 h 04 m Dec. +17° 05 ¢ (mag. 6)

(78) WZ Sagittae R.A. 20 h 07 m Dec. +17° 40 ¢

After exploring the two striking little crowds of stars around 13 and 15 Sge, 1° apart in a rich region of the Milky Way and easy to fi nd just 2° below g Sge, the ‘point’ of the Arrow, examine the position of another recurrent nova, WZ Sge, 2° west of 13 Sge. We may be due for another outburst of WZ, which is normally invisible at mag. 14–16: it brightened to mag. 7.0 in 1913, to 7.7 in 1946, and to 8.6 in 1978. According to Burnham, the light curve and spectrum of WZ Sge sug-gest that it is a binary consisting of a red dwarf and a white dwarf in a very tight orbital dance: they may be closer to each other than Earth is to the Moon. The chart (Fig. 8.38 ) shows stars for ‘hopping’ from g Sge through 13 to WZ.

Fig. 8.38 38 Finder chart for WZ SgeObject: WZ SagittaeType: Recurrent nova Norton’s 2000.0 chart: 13 Uranometria 2000.0 chart: 163

176 8 Targets

Scutum (June–July)

Although the Shield may never climb very high in your sky, and you may not see the wonderful Milky Way condensation that is its star cloud from a light-polluted site, try:

(79) S 2391 R.A. 18 h 49 m Dec. −06° 01 ¢

This fi ne double star (mags. 6.5, 9.5, sep. 12″), just over 1° south of b Sct, is actually a triple, but there is no chance of glimpsing the mag. 14 companion with modest instruments. The brighter of the two visible stars looks unusually white. Moderate power.

Serpens (May–June)

The divided Snake offers many famous targets. Thanks to the Hubble Space Telescope, the ‘Pillars of Creation,’ which are the dust towers of the Eagle Nebula (M16), are now probably the world’s best known deep-sky object. Serpens’ lesser known pleasures include:

(80) R Serpentis R.A. 15 h 51 m Dec. +15° 08 ¢

Easy to fi nd with binoculars between b and g Ser (Fig. 8.39 ) when at its maximum of mag. 6.9, R Ser is a typically red long-period variable. Its period is 356 days. At its minimum, it will have faded to about mag. 13. It is about 1,000 l.y. away.

(81) IC 4756 R.A. 18 h 39 m Dec. +05° 25 ¢

This extensive cluster, 1,400 l.y. away, appears twice as wide as the full Moon. It is worth looking at with both high powers and very low powers, or binoculars. High magni fi cation brings out many stars seemingly crowding into its central region, enclosed in a rough pentagon of its brightest members, while a ×20 binocular fi eld renders the surprisingly large cluster in its entirety. NGC 6633 in Ophiuchus (see above) is 3° away to the northwest.

177Taurus (November–December)

Taurus (November–December)

(82) NGC 1647 R.A. 04 h 48 m Dec. +19° 03 ¢

A really ‘neglected neighbor,’ completely outclassed by the nearby Hyades, but still a fi ne object in its own right. With a low power, two main streams of stars are obvi-ous, with a suggestion of many more just beyond the limit of vision. With south facing upwards, through an inverting telescope, the fanciful observer might see 1647 as a pyramid standing on its apex. See chart for HU Tauri (below).

(83) S 670 R.A. 05 h 17 m Dec. +18° 27 ¢

A high power will reveal the dual nature of this system (mags. 7.5, 8; sep. 2.5″), and possibly its colors (white, blue), but the intriguing thing about S 670 is the ‘driveway’ of several faint stars leading up to it from the south. Not far away northwards is:

Fig. 8.39 Finder chart for R SerObject: R SerpentisType: Long-period variablePeriod: 356 days Norton’s 2000.0 chart: 11 Uranometria 2000.0 chart: 200

178 8 Targets

(84) S 680 R.A. 05 h 19 m Dec. +20° 10 ¢ , with a dull red mag. 6 primary and a dif fi cult mag. 10 secondary (sep. 9″), at the start of a pretty little east-west chain of stars containing:

(85) S 674 (CD Tau) R.A. 05 h 18 m Dec. +20° 10 ¢ : mags. 6, 9; sep. 10″.

There are several pairs in this region: try sweeping with a medium power.

(86) HU Tauri R.A. 04 h 38 m Dec. +20° 40 ¢

A relatively bright eclipsing binary, normally at mag. 6.0 and easy to locate: 4° almost due north of Aldebaran, and exactly halfway between e and t Tau. At inter-vals of 49.4 h (2.06 days), it dims to mag. 6.8, the whole event being well within the range of small binoculars. The chart (Fig. 8.40 ) shows stars between Aldebaran and HU Tau, with NGC 1647 (see above) in the fi eld.

Fig. 8.40 From Aldebaran to NGC 1647 and HU TauObject: HU TauriType: Eclipsing binaryPeriod: 2.06 days Norton’s 2000.0 chart: 5 Uranometria 2000.0 chart: 134

179Triangulum (October–November)

Triangulum (October–November)

(87) M33 (NGC 598) R.A. 01 h 34 m Dec. +30° 39 ¢

The main attraction of Triangulum, the extensive face-on spiral galaxy M33, is a notoriously dif fi cult object to locate with moderate instruments because of its low surface brightness. Even in good dark skies, a thin haze or slight moonlight can veil it, and observers who suffer from any degree of light pollution might decide not to bother. Also, its large size (90 ¢ × 60 ¢ ) can throw some observers who are expecting to fi nd something smaller. Imagine my surprise then, when, on the night of October 5, 1989, I chanced a look at it in my moderately light-polluted sky through the 21-cm/8-in. and saw some ghostly but real detail! Exceptional sky clarity seems to be the key here, so, on rare, clear autumn nights, try M33. I used ×50 and sketched a vaguely ‘spiral’ core and a few nebulous knots (Fig. 8.41 ). A memorable evening. A borrowed broad-band fi lter improved the view slightly.

Fig. 8.41 M33Object: M33 (NGC 598) Instrument: 21-cm./8.5-in. re fl ector f/6Constellation: Triangulum Magni fi cation: ×50Type: Galaxy Sc Field diameter: 45´Magnitude: 6.7 Seeing: Ant. I-II Norton’s 2000.0 chart: 3 Light pollution: moderate Uranometria 2000.0 chart: 91 Date: 1989 October 5 Time: 2247 UT

Notes: Large, blotchy object, with a few ‘highlights’. Slight indication of spirality. Filter

180 8 Targets

(88) i (6) Trianguli R.A. 02 h 12 m Dec. +30° 18 ¢

Here is a fairly bright binary (mags. 5.3, 6.9) with a strong color contrast. It is easy to split with a high power (sep. 4″). Victorian astronomer Admiral William Smyth called the colors ‘exquisite,’ and chronicler of the stars Robert Burnham, Jr., saw them as ‘strong yellow and pale blue.’ Spectroscopy splits them both again. i Tri is 300 l.y. away.

(89) S 239 R.A. 02 h 17 m Dec. +28° 46 ¢

From i Tri, move one and a half degrees southwards and then 1° east, to fi nd this binary. The brighter component is listed as mag. 7, and its companion mag. 8, though they look fairly similar in brightness. What distinguishes them is their col-ors, with the primary a fairly unsurprising yellow, but the other star, according to my notebook, an ‘elusive steely-gray (?)’ color at ×108. Nineteenth-century observ-ers were also unsure: Reverend Webb saw the secondary as ‘bluish-gray,’ and Franks as ‘lilac.’

Ursa Major (February–March)

In early spring, the Great Bear prowls high above late at night in mid-northern latitudes. The most extensive of the exclusively northern constellations, covering 1,280 square degrees, it is a fertile area for seeking lesser-known deep-sky objects.

(90) a 2 Ursae Majoris R.A. 09 h 10 m Dec. +67° 10 ¢

This is another binary whose orbital changes you can follow, with high magni fi cation, as the years go by. Gold and greenish-white, the two components are close, sep. 2.4″ (increasing). The 1917 edition of Webb’s Celestial Objects for Common Telescopes gives the position angle for 1912 as 147°, M. Duruy measured it at 45° in 1943, and Burnham’s Celestial Handbook has the 1962 p.a. as 20°. The secondary has now passed its northerly position (p.a. 0°) as it pursues its 700-year swing around the primary.

(91) 23 Ursae Majoris R.A. 09 h 31 m Dec. +63° 04 ¢

23 UMa is an unremarkable double, mags. 3.7, 8.9, sep. 22″. The challenge lies in spotting an optical neighbor, a mag. 10 star at 99″ south preceding. In my ×50 fi eld

181Ursa Major (February–March)

(diameter of fi eld 45 ¢ ), a line from the primary through this faint companion points towards the compact elliptical galaxy NGC 2880 (see below).

(92) NGC 2880 R.A. 09 h 30 m Dec. +62° 30 ¢

For a galaxy of mag. 12.7 (Burnham), 2880 was surprisingly clear on a calm night through the medium-power ×50 eyepiece (Fig. 8.42 ). It looked strongly pear-shaped, widening towards the preceding end, and of uniform brightness right across. The line from 23 UMa, if continued through the galaxy, leads to a pleasing white triple star, 4 arc minutes away. I have been unable to discover its designation.

Fig. 8.42 From 23 UMa to NGC 2880Object: NGC 2880 Instrument: 21-cm./8.5-in. re fl ector f/6Constellation: Ursa Major Magni fi cation: ×50Type: Galaxy E3 Field diameter: 45´Magnitude: 12 Seeing: Ant. I-II Norton’s 2000.0 chart: 1 Light pollution: moderate Uranometria 2000.0 chart: 23 Date: 1990 July 25 Time: 2318 UT

Notes: Faint and featureless, pear shaped. At limit of vision

182 8 Targets

(93, 94) 83 Ursae Majoris R.A. 13 h 41 m Dec. +54° 40 ¢

S 1795 R.A. 13 h 59 m Dec. +53° 05 ¢

These two objects form part of the string of stars of mags. 5–7 curving away from Mizar ( z UMa) towards i and k Boötis.

83 UMa is a late-stage red star, mag. 4.7, spectrum M2, and usually fairly unremarkable. Burnham recommends ‘an occasional curious glance,’ since, on August 6, 1868, Birmingham recorded a short-lived outburst by this star. Its appar-ent brightness had increased to that of d UMa, a rise of 1.4 magnitudes to mag. 3.3. By August 7, it had sunk back to its previous state.

S 1795 (mags. 7, 9.5; sep. 7.7″) has a fi ne white primary, and the faint secondary can appear bluish. A neat pair at ×108.

(95) b 918 R.A. 11 h 58 m Dec. +32° 20 ¢

A run-of-the-mill binary, with one star much brighter than the other, in a sparsely populated fi eld? b 918 (mags. 7, 13; sep. 7.5″) looks just that, but on a really clear night, without moonlight or haze and with good seeing, use averted vision to seek three faint smudges preceding in R.A., all galaxies: NGC 3991, 3994 and 3995 (Arp 313), in the same fi eld even with a fairly high power.

(96) NGC 3992 R.A. 11 h 57 m +53° 22 ¢

You might assume that 3992, a mag. 10.9 barred spiral galaxy, is part of the same group as 3991, 3994 and 3995 (above), but the great extent of Ursa Major becomes apparent when you realize that it is 21° to the north of them, in the same low-power fi eld as g UMa (Phad). Sometimes referred to by Owen Gingerich’s 1960 appella-tion M109, it is a beautiful object in photos, shaped like a slewed Greek q . There is a fi ne photo of 3992 in Sky & Telescope , July 1985, p. 32. The sketch (Fig. 8.43 ) shows my impression of it on a clear February night in 1992, when it was almost at the zenith. I described the large inner brightness, which bulges slightly north-wards, as ‘bean-shaped’; a fainter oval glow surrounds this at ×108. Distance 60 million l.y.

183Virgo (March–May)

Ursa Minor (May–June)

(97) p 1 Ursae Minoris ( S 1972) R.A. 15 h 29 m Dec. +80° 28 ¢

A very easy binary for a low-power eyepiece (mags. 6.5, 8; sep. 31″), with a faint (optical?) companion (mag. 11.5) at p.a. 104°. Both main stars are Sun-like, both yellowish, though Franks saw the mag. 8 as ‘bluish-white.’ Nearby p 2 ( S 1989) is another binary, but it is dif fi cult to split at 0.7″ (1975 estimate). Look 2.5° north from z (mag. 4.3), and 15 min forward in R.A.

Virgo (March–May)

Virgo holds more than just galaxies! In my trawls through this constellation, steeped in skyglow from Poole, over the years, in a usually fruitless effort to fi nd many of the hundreds of galaxies shown on charts such as Uranometria 2000.0 , I’ve encountered other things…

Fig. 8.43 NGC 3992Object: NGC 3992 Instrument: 21-cm./8.5-in. re fl ector f/6Constellation: Ursa Major Magni fi cation: ×108Type: Galaxy SBb Field diameter: 21´Magnitude: 10.9 Seeing: Ant. III Norton’s 2000.0 chart: 9 Light pollution: moderate Uranometria 2000.0 chart: 47 Date: 1992 February 4 Time: 2320 UT

Notes: Some structure apparent, bean shaped nucleus, bulging to SW

184 8 Targets

(98) 17 Virginis R.A. 12 h 23 m Dec. +05° 20 ¢

Failing to fi sh up any of the dim galaxies which crowd the fi eld, I found some con-solation in this binary (mags. 6.5, 9; sep. 19″). The primary is a rather dull white, and, although there are some intriguing reports in Webb’s Celestial Objects… of colors as various as orange, blue and purple for the secondary, it looks much the same as its neighbor. Moderate power.

(99) g Virginis (Porrima) R.A. 12 h 42 m Dec. −01° 26 ¢

A showpiece among the visual binaries, with twin yellow F-type stars (both mags. 3.65). g Vir, looking like the ‘remote headlamps of some celestial auto’ (Burnham), has been closing fast since its maximum 6″ separation in 1920, and appeared single through amateur telescopes by 2007, when the stars were a mere 0.3″ apart. When will you fi rst be able to split this pair as they move away towards apastron? Erich Karkoschka’s information-packed Observer’s Sky Atlas lists two-yearly separations for this binary until the year 2015, by which time it will have opened to 2.2″.

Vulpecula (July–August)

(100) NGC 6940 R.A. 20 h 35 m Dec. +28° 15 ¢

The Veil Nebula (NGC 6960 and 6992), the brightest part of which is at the abso-lute limit of vision from my observing site, shares its niche below the eastern wing of Cygnus the Swan with this large, attractive cluster of many faint stars just to the southwest of it and across the border in Vulpecula. 6940 can be surprisingly bright through 10 × 50 binoculars. Through the telescope, with a fairly low power, you fi rst see a line of three brighter stars, and a neat pair 20 ¢ away; but use averted vision, and the faint riches between come to light (Fig. 8.44 ). The area within the dashed line on the sketch was a mass of unresolved ‘stardust’ at ×50. The cluster is 1,500 l.y. away.

If you decide to try for some (or all!) of the objects in this list, I hope that fi nding them and forming your own impressions will give you as much pleasure as I have had in choosing them from my frayed notebooks, reminiscing on nights well spent beneath the stars.

For updated information in the list above, I am indebted to Dr. Andrew Hollis (British Astronomical Association Remote Planets Section), Guy Hurst (UK Nova/Supernova Patrol), Brian McInnerny (BAA Variable Star Section), Roger Pickard (BAA Variable Star Section), and Colin M. Pither (double stars).

185Vulpecula (July–August)

I would be grateful for any additional or corrected information on any of the objects at [email protected] .

Fig. 8.44 NGC 6940Object: NGC 6940 Instrument: 21-cm./8.5-in. re fl ector f/6Constellation: Vulpecula Magni fi cation: ×50Type: Open Cluster Field diameter: 45´Magnitude: 6.5 Seeing: Ant. INumber of stars: ~100 Light pollution: moderate Norton’s 2000.0 chart: 13 Date: 1997 July 25 Uranometria 2000.0 chart: 120 Time: 2334 UT

Notes: Very rich aggregation in southern half of cluster. A sparkling fi eld

http://[email protected]

Dark Future?

Part III


Light Pollution Solutions for the

Twenty-First Century

Chapter 9

The task of confronting and reversing light pollution, which has erased much of the detail of the night sky since the mid-twentieth century, has been great. Campaigners have largely succeeded in making the general public aware of the problem. Most people now realize that light at night has its ‘dark’ side. Sadly, there are still many astronomers, both amateur and professional, who do little or nothing to combat light pollution, believing perhaps that the battle is lost or the hill too steep to climb (Fig. 9.1 ).

Far from being lost, the battle for darker skies is making good progress. Most local authorities are much more amenable nowadays to taking action and spending money on replacing old-stock lights with good designs, and some switch them off when not needed. The lighting industry is producing a large range of sky-friendly (though often over-bright) designs. Governing bodies across the world are treating the subject of light control with the seriousness it deserves and enacting legislation. Examples include the UK with its Clean Neighborhoods Act, the Czech Republic, Slovenia, Lombardy and other Italian regions, France, Chile, Liechtenstein, and cities in the United States and Canada such as Tucson, Phoenix and Calgary.

Between 2003 and the end of the decade, the city of Calgary replaced nearly 40,000 of its old-stock streetlights with downward-directed types at a cost of $3 million – a scheme that more than paid for itself in energy savings in only 2 years. In the UK, the Science and Technology Select Committee (2003) and the Royal Commission on Environmental Pollution (2010) both produced reports fully sup-porting control on ‘over-the-top’ lighting and recommending government action. And even in high places, light control is sparking interest. A representative of the Campaign for Dark Skies was invited to a science reception at Buckingham Palace to meet Queen Elizabeth II in 2006, a meeting during which Her Majesty stated that

190 9 Light Pollution Solutions for the Twenty-First Century

her technical advisors would be looking to improve the fl oodlighting of the palace; and the CfDS coordinator was awarded the MBE (Member of the Order of the British Empire) medal in the 2010 Queen’s birthday honors list.

So the tide is beginning to turn. Edward Camplin, not an astronomer but a professional lighting consultant, wrote in early 2001, commenting on the need to avoid light intrusion in the countryside: “The movement started internationally by astronomers to regain and retain dark skies has become a serious factor in the planning of lighting.” The IDA, CfDS and numerous other organizations (see Appendix 2 ) have made light pollution a talking point, not just among astronomers but in the media (Fig. 9.2 ), in legislative assemblies, in lighting professionals’ jour-nals and in legal chambers. Primary-school children and experienced politicians know the meaning of the term. It now appears in dictionaries as a separate entry. Organizations as varied as countryside preservation campaigns, wildlife groups, ornithologists and guideline bodies at the forefront of the lighting and engineering professions are playing an active role in spreading the word that quality lighting is achievable and desirable.

The media are also treating the subject seriously. For example, in 2010, BBC Television’s Inside Out program devoted itself to the subject of light pollution, visiting several British towns at dead of night with dark-sky activists to fi lm and comment on cathedrals fl oodlit when there was nobody about to see them, and

Fig. 9.1 A hill NOT too steep to climb: Bath University’s sports lighting, seen in this photo taken in 2000 by Mike Tabb, has now been replaced with FCOs and the skyglow has been mini-mised. The scheme won the BAA’s Good Lighting Award

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191Light Pollution Solutions for the Twenty-First Century

wonder at the sight of garishly light-washed public buildings, brightly lit but empty car parks, and light halos over distant towns.

To throw the brake on a runaway vehicle, it is fi rst necessary to be on board. Public opinion will turn against light pollution only if information is readily avail-able and the public educated about the problem. To bring the optimum night sky to everybody, whether they live in downtown Los Angeles or an isolated cottage in the Highlands of Scotland, it is fi rst necessary to make sure that they know the basics of the light pollution debate. They need to understand the extent of the prob-lem, what has been lost to them, and its value. How is this education taking place? The public will consider obtrusive light as a potential and actionable nuisance, and feel determined to do something about it, or curb their own excesses, only if they know what we have lost from our environment to light pollution.

Those who make, sell, choose and install lights should automatically incorporate control of the direction of emissions, and consider the issues of avoidance of glare and over-lighting, just as those professionals who deal with domestic electrical fi ttings automatically put safety fi rst. The political will of legislators to protect the environment above, with real action instead of just consolatory statements, must be sparked by raised public awareness of the need to curb the misuse of light, for without public demand and a lively national debate, legislation is likely to be slow in coming.

Astronomers are everywhere and can be educators in many ways. Teachers, who are often the fi rst environmental champions children encounter, should know of the problem of excess light, and have the information at hand to be able to mention it alongside other forms of environmental harm. Their schools should invest in good lighting practices (Fig. 9.3 ).

Fig. 9.2 Bob presents the Campaign for Dark Skies’ Award of Appreciation to broadcaster John Humphrys, who has often involved himself in the dark skies debate (Photo: CfDS)


What should be happening, then, to turn the minds of all these different people (the public, the lighting professionals, legislators and educators, be they astrono-mers or teachers) towards solving the problem? What action is possible? Will there be a twenty- fi rst century solution to a twentieth-century problem?

What Should Manufacturers Be Doing About Light Pollution?

Many of the companies who design and create today’s lamps are taking note of the calls by CIE, CfDS, IDA, IESNA, ILP and other bodies for more sensitive lighting. All national and international lighting companies know that they can take measures either to protect the environment from waste light, or spoil it. IDA reports that U.S. manufacturers are absorbing the message, but its translation into good practice has been slower than desirable. UK companies are very willing, it seems, to retool and adapt, and “sky-friendly” lamps are certainly appearing in large numbers on Britain’s roads. The August 2011 issue of the ILP’s Lighting Journal has many pages featuring advertisements for downward-directed lights (not a globe light to be

Fig. 9.3 A well-directed outdoor light on a school in Luton, England

193What Should Manufacturers Be Doing About Light Pollution?

found!), many of them with LEDs as sources. The private lighting sector (“security” lights, principally) lags woefully behind, and vast numbers of environmentally unfriendly lamps still sit beside more thoughtful designs (Fig. 9.4 ) on the shelves of the hardware and DIY stores. These lamps are dealt with in more detail below.

The Lighting Journal is the respected of fi cial publication of the Institution of Lighting Professionals (ILP). Since the ILP is a keynote body in the international lighting community, reading its professional journal is a good starting point for anyone wanting to “take the temperature” of the industry.

The June/July 1995 edition of the Lighting Journal (mentioned in the fi rst edi-tion of this book) bore witness to the drift towards environmentally sensitive lumi-naires that began in the last decade of the twentieth century. The very fi rst double-page spread was an advertisement by a lighting company whose products are distributed worldwide. Most of the ad consisted of a photo of a star fi eld. The rest praised a local council for choosing fl at-glass road lamps, and mentioned the British Astronomical Association’s Good Lighting Award, presented to the council for “protecting the night sky with its pollution-free road lighting scheme…directed evenly onto the road below, and none invades the sky above.” Such advertisements were soon to become quite common, culminating in double-page spreads in the national press in the late 1990s, explaining the need to combat light pollution and promoting the sky-friendly products of an Italian company. Stars are now quite a common backdrop in the publicity of the lighting industry (Fig. 9.5 ), and (see above), the Lighting Journal now reads like a catalog for “sky-friendly” luminaires, with the caveat, as before, that many of them are too bright for the task.

Fig. 9.4 “Sky-friendlier” exterior light, illuminating only the area to be lit


Lighting engineer Michael Simpson, a past president of the Institution of Lighting Professionals, set the tone in 1995 with a leading article in the Lighting Journal , “Social Factors Behind the Development of Outdoor Lighting.” Simpson began with a review of the history and bene fi ts of outdoor lighting, but then wrote with less enthusiasm about the “amorphous yellow glow… spreading across the countryside… and never mind the spill or quality.” In his opinion, a “metamor-phism” had been occurring within the lighting industry during the early 1990s: “We were learning that outdoor lighting is more than just fi lling the space with light; learning that it is more than just a way of making our roads visible to motorists; learning that sensitivity in design is equally as important outdoors as it is indoors; and learning to take care of our environment.” The environmental/astronomical community is seen as important and worth listening to: “The environmentalists are concerned about the impact the equipment has on the landscape whether by day or night. In addition we have the astronomers, who are concerned about the amount of arti fi cial light that is scattered in the atmosphere… The astronomical lobby has

Fig. 9.5 An advertisement at a lighting exhibition, using stars as a feature


been particularly effective in persuading us that direct upward light must be reduced…With the recent passing of Halley’s Comet (1985-86 – BM), one com-mentator records the fact that his grandparents witnessed the previous passing with the naked eye; he had to make do with television pictures. It has been calculated that the effect of skyglow over London will reduce the visibility of stars by four stellar magnitudes. This means that the Pole Star completely disappears… for mil-lions of potential stargazers. Bearing in mind the importance of the stars for many early civilizations and travelers, and the place of astronomy in the National Curriculum, this is not a legacy we should perpetuate.” Beneath these words appeared a composite satellite view of Earth at night, showing the tracery of wasted light rising from the world’s inhabited areas. Simpson concluded this section with the observation that “the road lighting community has responded well to environ-mental pressure.”

Since 2000, “sky-friendlier” road lights have come on stream in large numbers (Figs. 9.6 , 9.7a, b ), though the 30-year lifetime of the average lamp means that the replacement of old-stock, less well directed lighting cannot be an overnight process as local authorities fi nd themselves short of money in these dif fi cult times.

Driven by competition and by environmentally aware voices within the industry, by the demands of highway engineers for more directional lighting, and by the astronomers’ continued publicizing of the need for improvement, the change

Fig. 9.6 “Sky-friendlier” FCO lights (black casings) replace old LPS types at a rural roundabout


towards more environmentally friendly practices within the road-lighting industry has accelerated. Visiting exhibitions and conferences staged by the industry, mem-bers of the Campaign for Dark Skies are increasingly impressed with both the directionality of the lights on show and the forward-looking ideas expressed by their makers.

Fig. 9.7 ( a ) Glare and skyglow from a rural roundabout lit by old LPS lamps; ( b ) the same scene after re fi tting with cut-off lamps: sideways glare and skyglow are much reduced (Photo: John Ball)


If it’s getting better, why hasn’t sky glow disappeared? Why does glare remain a feature of the night-time landscape? Why are people still complaining about new lights that cause light intrusion? Part of the answer lies in the fact that things are not going in such a positive direction in other enclaves of the industry. Domestic and electrical retailers still offer basic, excessively bright ‘security’ lights, stacked high and sold cheap. Ironically, some of the retailers of these units claim that all their products are vetted for environmental awareness. Sometimes these lights are used as a cheap alternative by small sports clubs for fl oodlighting, and are almost invariably poorly focused upon the playing area. Sports lights are nowadays among the worst offenders, engendering more complaints about lighting than in any other application.

Environmentally sensitive light control within the average and by now “traditional” 300 or 500 W home “security” light is a rare thing (Fig. 9.8 ), and it is uncommon to see a set of instructions inside the packaging offering advice on sen-sitive mounting. The usual angle at which these are set is with the front glass at nearly 90° to the ground, and many such lamps have their passive infrared (PIR) sensors mounted beneath them, so that their light cannot be kept below the horizon-tal by tilting them downwards. The effectiveness or otherwise of these units as deterrents to wrongdoers has already been covered. Bulkhead lights (Fig. 9.9 ), usu-ally mounted vertically against walls, also contribute to upward light spill, and in many cases throw 50% of their emissions skywards. A leading member of the ILP has stated that “there is no task for which bulkhead lights are used that couldn’t be better done by a different kind of unit.”

Fig. 9.8 Glare from an indifferently mounted ‘security’ light, 200 m away, which forced mem-bers of the Wessex Astronomical Society to abandon one of their traditional observing sites in the New Forest


If the mainstream lighting industry is generally positive about light pollution, why don’t they think along similar lines when making these smaller but often much brighter and more intrusive products? Firstly, the great majority of ‘security’ lamps are imported from the Far East and are not made by the large UK- or U.S.-based road lighting companies. Fewer constraints seem to apply, and the few “anti-light-pollution” domestic exterior lights on the market tend to be made locally. It falls therefore to the retailers of such lamps (and more speci fi cally their buyers) to respond to the prevailing climate, and to use whatever in fl uence they have over the design and manufacture of their suppliers’ products to improve the situation. Relatively small numbers of “sky-friendly” domestic lamps can be found in retail outlets, looking lost beside great piles of “Rottweilers.” Bulkhead lights are sold more for their daytime appearance than their night-time performance and are as likely to dazzle passers-by as reveal what might be going on in their vicinity.

The customer, too, should be a regulator of the quality of the product bought, and much modern legislation exists to ensure this. So, education is another part of the answer: if those who believe, rightly or wrongly, that security can be assured by mounting lights on their outside walls know what kinds of lights might conceivably have some effect, and, more importantly, what amount of light to use and where to direct it, then the market will be more consumer-led.

Earlier, the point was made that minimizing light pollution is not about switch-ing off all lights, nor just about correct design of lamp housings to put all the light where it is needed. An important aspect of the solution is putting the right amount of light onto the surface to be illuminated, and the lighting industry, with its exper-tise and advisory capacity, can counsel clients (as many fi rms already do) as to the minimum light output for the task, insisting (until legislation can insist for them) that more light is not always good light.

Fig. 9.9 Bulkhead light

199What Should Legislators Be Doing About Light Pollution?

The experts, the lighting professionals, are the only ones who can physically solve the problem of light pollution. It will not be directly solved by strident envi-ronmentalists or lobbying astronomers, who do not make lights. Through improved design, education within the industry and the promotion of a climate rewarding good practice, professionals will be increasingly aware of the light pollution issue and will continue to move towards the solution. CfDS, IDA and other bodies will continue to work alongside them.

What Should Legislators Be Doing About Light Pollution?

Legislators in central government call frequently for the enactment of environmen-tal measures, put their signatures to international environmental agreements (i. e., Agenda 21, the Kyoto protocol and the – inconclusive – Copenhagen conference), wring their hands about the effect that technological progress is having on climate change, and pay lip service to the enforcement of energy-saving directives. Meanwhile, light pollution continues to fall outside the mainstream of legislation to control environmental pollution. Indeed, legislators deliberately excluded light from the list of potential pollutants when the British Parliament debated pollution controls in the early 1990s, and the U.S. government has in recent years blown hot and cold about its commitment to the reduction of greenhouse gases.

Environmental agencies worldwide have committed themselves to international agreements on energy savings and atmospheric and environmental protection; they have accepted targets for these aspects. While recognizing and publicizing good practice (Fig. 9.10 ), friends of the night sky in all signatory countries should con-tinue to insist to their elected representatives, from both local and national govern-ment, that these targets will include the wasted energy from poor-quality lighting.

Islands of good practice stand out. For example, Michigan’s recreational areas have had protection from obtrusive lighting since the success of the Lake Hudson Dark Sky preserve in the early 1990s. There are dark-sky reserves and communi-ties, and “star parks,” in many countries, where care is taken to control local light-ing. A list of European and North American dark-sky reserves can be found at en.wikipedia.org/wiki/Dark-skypreserve .

Galloway Forest Park in southwest Scotland encloses 300 square miles of unspoiled mountains and forests. It became western Europe’s fi rst dark-sky reserve in 2009, and the Scottish Forestry Commission works with both local and interna-tional dark-sky organizations to keep this remote and beautiful area (Fig. 9.11 ), population just a few hundred and with its own public-access observatory, light-pollution free. Some (but not all!) of Britain’s areas of natural beauty and national parks (Fig. 9.12 ) have a policy of controlling upward light, following the recom-mendations of the ILP guidance notes (see Appendix 5 ). Exmoor National Park became England’s fi rst dark-sky reserve in October 2011. But the central govern-ment was slow to react during the 1990s. As part of an initiative that spanned the decade, the UK government’s Department of the Environment (DoE) targeted

http://en.wikipedia.org/wiki/Dark-skypreserve

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Fig. 9.11 Galloway Forest Park

Fig. 9.10 One government department which has set the trend with well-directed lights: the UK Highways Agency’s Martin Hazle ( left ) receives the British Astronomical Association’s Good Lighting Award from CfDS committee member Stuart Hawkins (Photo: CfDS)

201What Should Legislators Be Doing About Light Pollution?

schoolchildren as part of an energy consciousness campaign, through lea fl ets featuring friendly dinosaurs voicing the slogan “Wasting Energy Costs the Earth.” The dinosaurs told the children, and rightly too, that energy-saving light bulbs in the house were a good thing.

In spite of entreaties to the DoE by CfDS that a lot of energy was being wasted by environmentally insensitive exterior lamps far more powerful than any found on walls or ceilings indoors, the DoE never mentioned in their literature the need to save energy outside the walls. The standard answer from central government in the 1990s was that “education is more likely to lead to a solution of the problem of light pollution than legislation”; and as environmentalists worked to educate, the ‘Rottweiler’ lights were still allowed to appear, bolted to walls everywhere.

At last, in 2003, the UK government’s Science and Technology Select Committee (see Introduction) decided to look into the subject of lighting and the environment, and the 2005 Clean Neighborhoods and Environment Act introduced limited legis-lation (with no mention of the night sky, and with some unwarranted exceptions – see Chap. 3 ).

Governmental environment departments are charged with the protection of the entire environment. They must acknowledge the value of that part of the environ-ment that has suffered the most damage from human intervention over the last half-century and has no protection in law throughout most of the world – the starry sky.

Fig. 9.12 Night sky over Exmoor, south-west England: a National Park with a good lighting strategy. Location: Winsford Hill (Photo: David Brabban)

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The actuarial approach seems to be at the forefront of legislators’ thinking. Light pollution, light intrusion and the disappearance of the night sky don’t kill people (at least, not very often), and a generation brought up beneath orange skies don’t seem to complain about what they’ve never had the chance to see. Surely there are forms of pollution that require far more urgent action?

However, it is the prime duty of any legislature to ensure the continuation of an acceptable quality of life for its citizens, and anyone who has ever had the chance to see the untainted dome of the stars, and to enjoy the bene fi ts that the darkness of the night can bring to their bodily rhythms and peace of mind, will testify that the veiling of the night sky, and the lack of nocturnal tranquility, are environmental tragedies of some proportions. Robert Macfarlane (see Introduction) put it succinctly when he wrote that “our estrangement from the dark (is) a great and serious loss.”

Simple but effective government measures, on a sensible, evolutionary times-cale, to bring back that quality of life would be:

The banning of all domestic exterior lighting whose design and wattage cause • glare and emission above the horizontal; A further acceleration of the trend in well directed road lighting; • • Real powers for environmental of fi cers, equipped with standardized measuring devices, to intervene in cases of nuisance by light; And a proper education policy about light pollution, in parallel with other forms • of environmental education.

What Should Local Authorities Be Doing About Light Pollution?

Much of the public lighting we see around us is bought with public money and installed by local authorities. It can be very well done, or very badly done (Fig. 9.13 ), and for our money we can get either a sensitively lit environment with a reasonable chance of seeing the stars, or a garish light-show which de fi es the heavens.

In the absence of directives from the central government, there is still much that a local administration can do to mitigate light pollution if it is so minded. Experience has shown that, with concerned individuals in administrative positions which give them control over relevant decisions, and with the right amount of persistent and friendly pressure from local residents concerned about the environment above, things can happen which will forestall poor lighting.

An early and de fi nitive statement that might serve as a model for other adminis-trations was that of the city of Tucson, Arizona, an astronomically sensitive area with major observatories not far away. Extracts from the Revised Tucson and Pima County Outdoor Lighting Control Ordinances are reproduced in Appendix 11 .

Many districts and boroughs in the UK have adopted ‘Light Pollution’ or ‘Intrusive Light’ clauses into their updated local plans (Fig. 9.14 ). This helps the

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203What Should Local Authorities Be Doing About Light Pollution?

Fig. 9.13 Stonehenge silhouetted against spill light from the nearby town of Amesbury (Photo: Grant Privett)

Fig. 9.14 East Dorset District Council have light pollution on their agenda: leader Don Wallace receives the Good Lighting award (Photo: EDDC)


planning departments of local authorities to ensure that good-quality external light-ing schemes are incorporated into plans at approval stage. Poorly designed or over-bright schemes can be referred back to the applicant for modi fi cation. In this way, poor lighting schemes are nipped in the bud before they become a problem.

Here are brief extracts from adopted local plans in the UK that might serve as examples of good practice to local councils in any country.

Extracts from Local Plans: Examples of Good Practice

Policy E6 Swale Borough Local Plan 1994

The Borough Council will seek to minimize light pollution. Details of any lighting scheme required as part of any new development should be submitted as part of the planning application. Applicants will be expected to demonstrate to the local planning authority that the scheme proposed is the minimum needed for security and working purposes and that it minimizes potential pollution from glare and spillage, particularly to residential and commercial areas; areas of nature conserva-tion interest; and areas whose open and remote landscape qualities would be affected.

East Hampshire District Council Local Plan

Details of any external lighting scheme required as part of any new development should be submitted as part of the planning application. In order to minimize light pollution and increase energy ef fi ciency, the District Council will need to be satis fi ed that the lighting scheme proposed is the minimum required for security and working purposes and that it minimizes potential pollution from glow and spill-age. On the edge of settlements and in rural locations, landscaping measures should be provided to screen the lighting installation from view. Conditions will be attached to any fl oodlighting approvals given for evening usage of sport facilities such as pitches, tennis courts and golf driving ranges to control light intensity, light spillage and hours of use.

Environmental Policy 6, Malvern Hills Local Plan

Applications for development requiring or likely to require external lighting shall normally include details of lighting schemes which will be expected to demonstrate that: the lighting scheme proposed is the minimum required to undertake the task, light spillage is minimized in the edge of town or village locations, or in rural areas, landscaping measures will be provided to screen the lighting installation from view

205What Should Local Authorities Be Doing About Light Pollution?

from the neighboring countryside areas, and there will be no dazzling or distraction of drivers using nearby highways.

Hinckley And Bosworth Borough Council

Light pollution is caused by excessive arti fi cial light being directed into the night sky. Outdoor lighting can cause intrusive and unnecessary pollution in both urban and rural areas, although it is in the countryside that light pollution is most notice-able. Excessive light in the night sky is visually intrusive and is also a signi fi cant waste of energy. The visibility of the stars is much reduced by light pollution.

It is therefore important in the interests of visual amenity and energy conserva-tion that light pollution is prevented and where possible reduced. Through good design of lighting, the reduction of light pollution should not con fl ict with the prin-ciples of crime prevention and safety.

Epsom and Ewell Local Plan

Arti fi cial light is increasingly being perceived as a form of pollution. Illuminated advertisements, fl oodlit sports facilities, security lights and street lights can all contribute to pollution such as skyglow and glare. They can damage visual amenity, disturb people’s sleep, and effect local ecology.

Planning control over arti fi cial light other than advertisements is generally lim-ited to new structures or works which are integral to other development. However, where planning permission for arti fi cial light sources is required the Council will seek to prevent detrimental impact on surrounding areas. Impact will be minimized by ensuring that arti fi cial light is carefully sited, appropriately shielded, directed only onto the speci fi c area where it is needed, and designed at the minimum height and brightness to serve its purpose. Where appropriate, the Council will use condi-tions to limit the hours of illumination. Developers’ attention is drawn to the Institute of Lighting Professionals’ publication ‘Guidance Notes for the Reduction of Light Pollution.’

Further measures that local administrations might take could be to survey local resi-dents on schemes whose visual impact would affect large numbers of them, such as mass replacement of streetlights and the long-term fl oodlighting of public buildings and churches (Fig. 9.15 ), to see whether the schemes have widespread support from those who might conceivably be contributing to the cost. SSE Electricity of fi cials did sterling work throughout the county of Dorset in the summer of 2011, visiting villages and towns all over the county to tell people about their replacement street-lights and to advise them on any concerns and objections. Local astronomers and environmentalists were invited to their meetings. Many administrations have issued pamphlets to residents, incorporating guidelines on reducing light pollution.


What Should Architects Be Doing About Light Pollution?

“More nightmare than nightscape”: this is how our over-lit and garish cities were described in the Royal Fine Art Commission’s booklet Lighten our Darkness , pub-lished as long ago as 1993. As a design concept, the lighting of structures and the actual lamps mounted on them for both daytime decorative effect or night-time fl oodlighting, are often viewed, it seems, in isolation from the wider surroundings. Worse still, clients ordering lighting for fl oodlighting exteriors might try to outdo neighboring schemes in brightness and general effect. The result is a garish, “more nightmare than nightscape” scene.

Individual elements of schemes are often overstated, in an attempt to “paint over” light falling upon them from local street lights or neighboring structures. The architectural merit of many buildings, far from being enhanced by fl oodlighting, is lost because the lights draw attention to themselves, rather than to what is being lit, with too-vivid colors or simply far too much power (Fig. 9.16 ). For buildings to stand out from the darkness, there has to be some darkness present . Indeed, do some of the buildings washed with light in our towns need to be lit at all? According to Professor Hal Moggridge, expert in landscape architecture and former

Fig. 9.15 Some church fl oodlighting is far too random, and allows a large fraction of emis-sions into the sky (Photo: Chris Baddiley)

207What Should Architects Be Doing About Light Pollution?

Commissioner of the Royal Fine Art Commission (now Commission for Architecture and the Built Environment): “Too much light can seem super fl uous, no more than a symbol of waste of energy. Lighting should not be seen as any more inherently desirable than darkness.”

Rural buildings may often be lit to draw attention to their architectural features at night. Does a certain Scottish castle look better fl ushed an unnatural green, the whole re fl ected in the nearby loch, or as a stark, dark shape picked out by moon-light against the inky black background of a pine forest? Does an isolated country church have more merit fl oodlit by orange lights concreted into the ground around it, reducing it to a bland monochrome façade and dazzling anyone passing through the churchyard at night, or would it look better with a bright white light source inside in the evening, projecting the beauty of the stained-glass windows, with perhaps a narrow-beam, highly directional LED spotlight or two outside carefully trained on features that deserve attention? Such value judgments do not really fur-ther the general debate about light pollution, since one person’s meat is another’s poison; but architects and design consultants can certainly exercise responsibility towards the environment both around and above the structures they wish to fl oodlight. Ian Phillips, Chairman of the Landscape Institute, summed it up in 1993 when he said at a conference on Lighting and Landscapes: “Too much lighting isn’t planned – it just happens.”

Many consultants already have the environmentalists’ and professionals’ concerns at heart when deciding on lighting strategies for new developments.

Fig. 9.16 A city nightscape, with buildings clamouring for attention


Lighting consultants Peter Wright and James Paterson, for example, have produced Understanding and Dealing with Obtrusive Light – A Practical Guide to Help Planners and Designers to Appreciate and Deal With Problems of Light Pollution ( www.lcads.com/pollution/ObtrusiveMain.html ). In Edinburgh Lighting Vision , issued by consultants Lighting Design Partnership, we read: “Arti fi cial light is a powerful tool, and needs to be used sensitively, selectively and imagina-tively, whether lighting a building, a street, a garden or a monument. Misuse results in visual distortion, incorrect visual information and, in the wider context, an imbalance between the numerous aspects that comprise a cityscape at night.” Carefully prepared schemes and a general consensus on what is needed to tone down the urban ‘nightmare’ could be the result of a proper, nationally agreed code of practice on lighting among architects and consultants – a code within which lights are not seen just as decorative adjuncts during the day, and a means of draw-ing attention away at night from all else and towards the structure on which they stand. The watchwords informing this code should be selectivity and collabora-tion : select the right buildings, the right times for them to be lit and the right times for them not to be lit, and the most appropriate, most environmentally sensitive lights. If schemes are to go ahead (in some British villages, church fl oodlighting schemes have been voted down, and many of the schemes that have been installed have appeared without public consultation), collaboration is necessary with local residents, environmentalists, and, most importantly, with other architects and con-sultants, through the channel of a local authority or chamber of commerce, to ensure that both the built and the natural environments are harmonized and respected, and townscapes enhanced rather than vandalized. Last but not least, those directly affected by proposed lighting schemes should have their say before any decision is made.

What Should Retailers Be Doing About Light Pollution?

Much of the responsibility for the current proliferation of poor-quality, over-bright ‘security’ lights lies with retailers, who claim (erroneously) that such units will help to deter crime. They are imported in large numbers and usually sold very cheaply. Many retailers do not readily respond to information passed to them by astrono-mers, environmentalists and by some lighting professionals, who agree that such lights are, in the main, insuf fi cient and environmentally insensitive.

Units with better light direction are fi nding their way onto the market. However, this is not accompanied by a decline in the promotion of less sensitive types. A well-known retailer claims that all its lines are environmentally sound. Although the origin of its timber products and the non-toxicity of its paints may well be praiseworthy, the range of exterior lights offered represents a ‘blind spot’ in this retailer’s environmental credentials. Tighter speci fi cations, including better shield-ing, sensible wattages and information in packaging, are surely not beyond the means of the DIY business, even if it adds a little to the price.

http://www.lcads.com/pollution/ObtrusiveMain.html

209Courses of Action

What Should Astronomers Be Doing About Light Pollution?

It is through astronomers, both amateur and professional, that the various threads of the solution can be woven together. They may not be designers or sellers of lamps, they may not manufacture them, and they may not belong to local adminis-trations (although some do, and have had great success in in fl uencing the choice of lighting), but what they can do is, individually or in groups, to make sure that all the interests mentioned here, all those who make, choose and install lights, know about the dark skies debate and re fl ect on it before those lights are made, chosen or installed. The prevailing mood among many astronomers, that the problem is just too far advanced and that their voices will not be heard against the ‘noise’ of tradi-tional assumptions about light, and powerful vested interests, is in error. IDA, CfDS and their counterpart organizations in other countries have proved that, from small beginnings, the dark skies message can be spread very widely. Improvement is pos-sible, and is happening. In many locations, the stars can be and have been regained. Shoddy lighting can be and has been swept away. Campaigners know that the vari-ous interested parties will often listen, so that changes in lighting can come about, slowly but surely. ‘Great oaks from little acorns grow’. The astronomers’ task is to accelerate those changes by publicizing the issue frequently, both as individuals and en masse . We, the astronomers, are never going to get all lights switched off, and most of us would not want to: we have the same lighting needs as everybody else. Enforceable controls over lighting, and a sane approach to its installation and positioning, are achievable goals.

Courses of Action

A good way, if you are an amateur astronomer, to start moving towards those goals on a local scale is to approach individuals and organizations with offending lights in your immediate area and point out that it could be much better done. Of course, many people do not feel comfortable (politely!) confronting offenders. They might be surprised at how often such approaches work. Those causing light pollution will usually listen, and if the problem is explained logically, they will probably take action. As long ago as 1998, a Scottish survey showed that the vast majority of people approached about poor-quality lighting did not even realize they were caus-ing a problem.

On a slightly less local scale, fi nd out who in your area is concerned about the spread of “over-the-top” lighting, with a view to forming an active pressure group. Use local media to air your views – they welcome “green” issues. Offer to talk to local groups who use regular speakers, and hold special public meetings of your astronomical society, at a dark site if you have one, to show people what they are missing in poorly lit urban areas. You may well know of a rural site from which the depredations of light pollution are very easily demonstrated, with a view of a dis-tant town’s myriad lights and the halo of waste above them blotting out the stars for


many degrees above the horizon, while the Milky Way remains tantalizingly visible vertically above. Invite local councilors, journalists, teachers, environmentalists, and owners of poor lighting to these places to make the comparison between starry and tainted skies. An explanation of the problem of light pollution at such a site, or a presentation of images taken there, may be worth many letters to local papers or talks to interest groups. You will be surprised at how many people care – most of them non-astronomers, and many of them of the older generation who can remem-ber what the night sky and a comfortable terrestrial nightscape should look like, and realize what they have lost.

Next, prepare letters and petitions (see Appendix 8 of this book) for local authorities from your supporters. Find out who is responsible within your local administration for choosing and installing outside lighting, and which individuals in the council are the most approachable and amenable to argument. Write to named individuals, asking them their views on the problem and what they are already doing about it. Quote the ordinance and local plans shown in Appendix 11 of this book and above in the “local authorities” section, and the advice from IDA and CfDS (Appendices 8 , 10 ).

A positive approach and politeness usually get results. “Broadsides” don’t win friends, carping criticism builds barriers, and baldly accusing someone of being a polluter is not wise. Have the facts to hand, such as published engineers’ guidelines, factsheets from IDA, CfDS and other organizations ( Appendix 2 ), and fi ndings such as those in Parts I and II, on lighting and crime and the cost of wasting energy skywards. Join IDA and CfDS to bene fi t directly from their updates, literature and support, and refer to their websites.

Public interest in astronomy is growing. Many astronomical societies reported an in fl ux of new members after the passage of Comet Hale-Bopp in 1997. There have been some notable recent eclipses, and spectacular television series on astron-omy. Casual dog-walkers at night are intrigued by the sight of the International Space Station slowly crossing the sky. The International Year of Astronomy in 2009 saw events and public observing sessions worldwide. Hotels and tourist of fi ces invite holidaymakers to come and admire the stars in dark places (for example, Pembrokeshire, Wales, featured its starry skies in 2009 on London Underground train advertisements). The “Spaceguard” movement is now taken more seriously by legislators (who now know what the consequences of a too close encounter with a 1-km asteroid would be). So many factors have re-sensitized people to the fact that there’s a universe out there. Astronomers should ride this tide, and stress in what-ever ways they can that this rediscovered environment could offer so much more if correctly protected. Schools and higher education establishments, as well as adult general interest groups, welcome talks on space-related topics. Consider giving talks to organizations as diverse as gardening clubs, senior citizens’ lunch groups, the Advanced Motorists’ Club – even local astrology clubs! Light pollution always creeps in there somehow…

Your over-lit neighbors may be skeptical on hearing you argue for light control. Surely, they will say, a well-lit neighborhood is essential in these crime-ridden days? Now’s the time to show them, “in the fi eld,” what “well-lit” means. Try three

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simple demonstrations described below that might clear their minds; they have certainly worked with people in many areas.

Ask neighbors with blinding, outward-facing security lights to stand in the street –while you walk towards their property, disappearing into the glare they emit. They will realize that their lights are really “anti-lights,” concealing rather than revealing, and they may well be moved to do something about it. If new, more downward-directed lamps are installed near your observing site, –people may complain that the street lights have lost their “sparkle” (they mean glare) and are dimmer, even though they may be of the same or even higher wattage than those they replace and light the road more ef fi ciently. Prove the effectiveness of the new lights by asking doubters to stand with you halfway between the columns, and ask them to read the 1-mm-high print on one of their credit cards. It is usually possible to do this, and dif fi cult for anyone attending this demonstration still to maintain that it’s dark between the lamps. Many neighbors have re-angled or re-sited lamps after looking through an –astronomer’s telescope. Occasional star parties will sensitize your neighbors to the existence and value of the environment above (Fig. 9.17 ). Few will not be moved by their fi rst view of the Perseus double cluster: “like opening a jewel box”, said my neighbor, who has installed a switch on her garden light and takes care to turn it off in the late evening. The rings of Saturn seen for the fi rst time

Fig. 9.17 Preparing for a garden star party


so impressed another person that he fi tted a lower-wattage bulb to his porch light to cut down glow generally in the neighborhood. Perhaps you can even arrange for offending ‘security’ lights to be triggered while their owner is stargazing with you, so that the effect can be appreciated fi rst-hand!

You may not be able to convince all your neighbors, especially in high-crime areas, that a dark environment can be as much of a deterrent to wrongdoers as a brightly lit one (see Chap. 5 ), but you can certainly make the point that a real human being outside at night is a far better security device than any lamp: an astronomer can take action if (s)he sees or hears anything suspicious, but a “secu-rity” light cannot.

Perhaps the greatest problem that concerned astronomers face is the gut reac-tion, which will sometimes come from even the most educated listener, that they are against lighting and want everybody to live in the dark. Accusations will fl y from groups and individuals who, rightly or wrongly, feel vulnerable when going about their legitimate business at night. So, introduce the fact that good-quality lighting means a more evenly lit environment early on in any presentation or dis-cussion; discuss the demerits of glare, and the possibilities of concealment through over-lighting or too-deep shadows. List the security and other bene fi ts of a properly lit terrestrial environment before you move on to the astronomical arguments. It is vital to remember that not everybody considers that the night sky is an important thing, and they have a perfect right if they wish to have different priorities, and other interests and leisure pursuits. Discuss the savings in energy and money that good lighting brings, since saving money and energy have far greater relevance than astronomy in most lives. Talk about the use and misuse of a ‘security’ light, and only then introduce non-astronomers to the beauty and value of the stars with some of the superb images that you or fellow astronomers have taken, or which are easily obtained from many sources. Stress that the ultimate solutions to light pollution mean that, in the words of David Crawford: “everybody wins.”

Every astronomer, amateur or professional, is potentially an interchange point in an enormous network of information about the problem of skyglow and how it may be addressed. Talk to anyone and everyone about it – but perhaps not too often: a skyglow bore is just as bad as any other bore – and be part of that network. Support and publicize the work of CfDS, IDA and other campaigners.

Light pollution is not a problem that will be solved at a stroke. Those working to turn the tide as the new century wears on should perhaps resign themselves to the fact that not they but their descendants will be able to see a truly worthwhile night sky from urban areas and from a sensitively lit countryside: this is an issue for the altruistic and patient! Darker skies will assuredly come to many of us (Fig. 9.18 ). Exactly when that becomes a general reality depends very much on how many of us make a noise about light-energy waste, and our persistence in doing so. I wish you clear skies.

http://dx.doi.org/10.1007/978-1-4614-3822-9_5


Fig. 9.18 I wish you clear skies

215B. Mizon, Light Pollution: Responses and Remedies, Patrick Moore’s Practical Astronomy Series, DOI 10.1007/978-1-4614-3822-9, © Springer Science+Business Media New York 2012

Appendix 1

The StarLight Conference 2007

Declaration in Defence of the Night Sky and the Right to Starlight (La Palma Declaration)

The complete document can be found at: http://www.starlight2007.net/pdf/StarlightDeclarationEN.pdf

The participants in the International Conference in Defence of the Quality of the Night Sky and the Right to Observe the Stars, meeting in La Palma, Canary Islands, Spain, on the 19th and 20th of April 2007, jointly with the representatives of UNESCO, UNWTO, IAU, UNEP-CMS, COE, SCBD, MaB, EC and Ramsar Convention,

Aware that a view of the starlight has been and is an inspiration for all humankind, that its observation has represented an essential element in the development of all cultures and civilisations, and that throughout history, the contemplation of the fi rmament has sustained many of the scienti fi c and technical developments that de fi ne progress;

Guided by the principles announced in the preamble of the Explanatory note con-cerning Proclamation of 2009 as International Year of Astronomy (33rd session of the UNESCO General Conference) that de fi nes the sky as a common and universal heritage and an integral part of the environment perceived by humankind;

Recalling that humankind has always observed the sky either to interpret it or to understand the physical laws that govern the universe, and that this interest in

http://www.starlight2007.net/pdf/StarlightDeclarationEN.pdf

216 Appendix 1

astronomy has had profound implications for science, philosophy, culture, and our general conception of the universe;

Recognising that the quality of the night sky and thus the capacity to access the light of stars and other celestial bodies within the universe is deteriorating at an alarming rate in several areas, that its contemplation is increasingly dif fi cult, and that this process faces mankind with the generalised loss of a cultural, scienti fi c, and natural resource with unforeseeable consequences;

Conscious that the deterioration of the clarity of the night space has started to emerge as a serious risk to the continuity of astronomic observations, a branch of science that presently provides a fl ow of direct and indirect bene fi ts which are increasingly valued;

Bearing in mind that the Rio Conference of 1992 proclaimed the necessary defence of the “integral and interdependent nature of the Earth”, and that this defence naturally includes the dimension of the night skies and the quality of the atmosphere;

Acknowledging that the Universal Declaration of Human Rights of Future Generations states that persons belonging to future generations have the right to an uncontaminated and undamaged Earth, with pure skies, and are entitled to enjoying these as the ground of human history of culture and social bonds making each gen-eration and individual a member of one human family;

Mindful of the validity of the Universal Declaration of Human Rights, adopted by the General Assembly of the United Nations, and of the different international dec-larations on sustainable development and the conventions and protocols concerning the environment – all these safeguarding cultural diversity, biological diversity, the landscape, and thus the conservation of cultural heritage and combating climate change, all of which have a direct or indirect in fl uence on the need to safeguard the clarity of the night skies;

Considering that the scienti fi c, cultural, educational, environmental, safety, and energy bene fi ts of preserving a dark night sky need urgent attention and action;

Aware of the need to establish ef fi cient and urgent alliances among the leading play-ers, whose decisions can have an in fl uence on reversing the process of degradation that is affecting the quality of the night sky, with a view to providing all the possible assis-tance needed to protect and conserve the cultural and natural heritage of Starlight;

APPEAL to the International Community, and, in particular, URGE governments, other authorities and public institutions, decision-makers, planners and profession-als, private institutions and associations concerned, the world of science and of culture, and all citizens individually, to adopt the following principles and objec-tives of this declaration:

1. An unpolluted night sky that allows the enjoyment of the contemplation of the fi rmament should be considered an inalienable right of humankind equivalent

217Appendix 1

to all other environmental, social, and cultural rights, due to its impact on the development of all peoples and on the conservation of biodiversity.

2. The progressive degradation of the night sky must be considered an imminent risk that must be faced, in the same fashion as the main problems concerning resources and the environment are addressed.

3. The conservation, protection, and revaluation of the natural and cultural heri-tage associated with night landscapes and the observation of the fi rmament represents a prime opportunity and obligation for cooperation in safeguarding the quality of life. For all decision-makers, this attitude implies a genuine chal-lenge involving cultural, technological, and scienti fi c innovation, requiring a major constant effort to enable us to rediscover the presence of the night sky as a living part of our heritage.

4. Access to knowledge, armed with education, is the key to allow the integration of science into our present culture, contributing to the advance of humankind. The dissemination of astronomy and the scienti fi c and cultural values associ-ated with the contemplation of the universe should be considered as basic con-tents to be included in educational activities, which require a clear and unpolluted sky and proper training of educators in these subjects.

5. The negative effects of emissions and of the increased intrusion of arti fi cial light on the atmospheric quality of night skies in protected areas have an impact on several species, habitats, and ecosystems. Control of obtrusive light must be a basic element of nature conservation policies and should be implemented in the management plans of the different types of protected areas to ful fi l their mission in protecting nature and biological diversity.

6. Mindful that a starry night sky forms an integral part of the landscape perceived by the inhabitants of every territory, including urban areas, the landscape poli-cies established in the different juridical systems need to adopt the pertinent standards for preserving the quality of the night sky, thus allowing them to guarantee the common right to contemplate the fi rmament.

7. The intelligent use of arti fi cial lighting that minimises sky glow and avoids obtrusive visual impact on both humans and wildlife has to be promoted. Public administrations, those in the lighting industry, and decision-makers should also ensure that all users of arti fi cial light do so responsibly as part of an integral part of planning and energy sustainability policies, which should be supported by light pollution measuring, both from the ground and from space. This atti-tude would involve a more ef fi cient use of energy so as to meet the wider com-mitments made on climate change, and for the protection of the environment.

8. Areas suitable for unimpaired astronomic observation constitute an asset in short supply on our planet, and their conservation represents a minimum effort in comparison with the bene fi ts they contribute to our know-how and to scienti fi c and technological development. The protection of sky quality in these singular places must be given priority in regional, national, and international scienti fi c and environmental policies. The measures and provisions must be made to safeguard clear skies and to protect such spaces from the harmful effects of light, radio-electric emissions, and air pollution.

218 Appendix 1

9. Among others, tourism can become a major instrument for a new alliance in defence of the quality of the night sky. Responsible tourism can and should take on board the night sky as a resource to protect and value in every destination. Generating new tourist products based on the observation of the fi rmament and the phenomena of the night, opens up unsuspected possibilities for co-operation between tourism stakeholders, local communities, and scienti fi c institutions.

10. Sites included in the World Network of Biosphere Reserves, Ramsar Wetlands, World Heritage Sites, National Parks, and all those protected areas which com-bine exceptional landscape and natural values relying on the quality of their night sky, are called for including the protection of clear night skies as a key factor strengthening their mission in protecting nature.

All the necessary measures should be implemented to inform and to raise awareness among all the main actors involved in protecting the night environ-ment, be it at local, national, regional, or international level, of the contents and the objectives of the International Conference in Defence of the Quality of the Night Sky and the Right to Observe the Stars, held on the Island of La Palma.

Final Resolutions

The International Conference in Defence of the Quality of the Night Sky and the Right to Observe the Stars considers it essential to make the following public appeals:

1. In consonance with the principles announced in this Declaration, the Conference invites the authorities of States to take appropriate measures in order to safe-guard the cultural and natural heritage of Starlight, and formulate actions plans to provide effective protection of night sky, particularly in areas of interest for astronomic observation, protected areas that are sensitive to the loss of natural light from the night, and places of special importance related to astronomical heritage.

2. The Conference agrees to refer the Declaration on the Defence of the Night Sky and the Right to Starlight to the Director-General of UNESCO for its acknowl-edgement and, if appropriate, recommendation to the Agencies and Bodies of the United Nations system as well as to the International Conventions related with the principles and objectives approached by the Declaration and other organisa-tions directly involved, such as the IAU (International Astronomical Union).

3. At the request of the Canary Islands Government, once it has been adopted at a meeting of the Canary Islands Government Council in April 2007, the Conference decides to submit a proposal to UNESCO through the Spanish Government to declare March 21st a World ‘Right to Observe the Stars’ Day. The campaign will be launched under the name “The World Night”.

4. The Conference proposes to the UNESCO-MaB Secretariat to present the fi nal conclusions and achieved agreements at the 3rd World Biosphere Reserves

219Appendix 1

Congress, to be held in Madrid in 2008, with a view to include night sky protection, if appropriate, into the new Action Plan for Biosphere Reserves, acknowledging the important role that Biosphere Reserves can play as a network of true sustainable development laboratories.

5. The Conference requests the fi ve Conventions in the Biodiversity Liaison Group, to examine the outcomes of its deliberations and, if appropriate, take to their governing bodies a combined view of the role of the conventions in helping increase protection for the night sky, understanding that this action will have positive effects on the conservation and wise use of biodiversity. The Conference also recommends to the IUCN (World Conservation Union) to examine this issue at its 4th World Conservation Congress foreseen for Barcelona in late 2008.

6. The Conference requests the UNESCO World Heritage Centre to inform the World Heritage Committee at its 31st session to be held in Christchurch, New Zealand, 2007, on the development of an agreement within the framework of the UNESCO Initiative “Astronomy and World Heritage” and Initiative “Starlight”, with a view to de fi ne a concept of “Starlight Reserve” in order to nominate prop-erties which can contribute by its exceptional night landscape to astronomical researches world-wide.

Additional Resolution of the Steering Committee and the Scienti fi c Committee

Having closed the Conference, and having adopted the “Declaration on the Defence of the Night Sky and the Right to Starlight”, in view of the importance of the agree-ments reached, provisions need to be made for the future. Continuity of the work and of the co-operation already achieved is of vital importance and, to consolidate the results achieved thus far, it is appropriate and necessary to follow up and imple-ment the principles of the Declaration and the recommendations for the Action Plan. To this end, the following decisions are adopted:

1. To create a Steering Committee to monitor the Declaration and its Action Plan (Starlight Initiative), made up of the international agencies and institutions rep-resented on the Conference Organisation Committee, with the addition of repre-sentatives of World Tourism Organization, European Landscape Convention, International Astronomical Union, Ramsar Convention, UNEP Convention on Migratory Species, Secretariat of the Convention on Biological Diversity, Spanish National Commission for UNESCO, as well as of any initiatives and organisations related with the different subjects, competences, and disciplines that have an impact on the protection of the night sky that may be required, once the Committee has decided to do so.

2. The Starlight Initiative Steering Committee shall ensure the dissemination, pro-motion, and circulation of the Declaration and its Action Plan, and its good implementation, following the recommendations of the Scienti fi c Committee and to engage in all and any kind of activities that guarantee its continuity.

220 Appendix 1

3. The Steering Committee is charged of the dissemination and follow-up of the Starlight Conference agreements and it would take on the responsibility to pres-ent the Declaration to and disseminate among the main stakeholders, including governments, local authorities, scienti fi c institutions, dark sky initiatives, and organisations involved in environmental protection, defence of cultural diversity, and promotion of sustainable development.

4. The Scienti fi c Committee shall also propose drafting reports, conducting stud-ies, campaigns, co-operation proposals, initiatives, and actions aimed at protect-ing the skies and enhancing their value, particularly contributing to the ful fi lment of the objectives outlined in the Declaration.

5. Among the speci fi c initiatives arisen from the Starlight Conference, which will be approached by the works to be developed by the Scienti fi c and Steering Committees, there are:

The establishment of a partnership with the Sustainable Energy Europe • Campaign and development of a joint initiative, with the collaboration of European Renewable Energy Council, aiming to develop actions approaching night sky defence and its relation with the promotion of energy saving, the ef fi cient use of energy and renewable energies. Development of a cooperation agreement between the Starlight Initiative and • the UNESCO World Heritage Centre through its thematic initiative “Astronomy and World Heritage”, that would also include the start of inter-national consultations aimed to develop the “Starlight Reserves” concept. To refer the Declaration to the European Parliament and the European • Commission in order to disseminate its principles and, if appropriate, adopt them at the most pertinent level, reminding that clear sky defence is an important component of the fi ght against climate change. To work jointly with the World Tourism Organization and ITR in order to • promote awareness and knowledge related with night sky as a resource to put into value, supporting the development of new responsible destinations and tourist products based on star observation and night sky resources. To strengthen cooperation and mutual support with the initiatives and organi-• sations involved in dark sky conservation, particularly with IDA (International Dark Sky Association). To work jointly with the European Landscape Convention to implement the • new dimension of night landscape within the Convention. To develop new ways of cooperation with organisations involved in culture • promotion, in particular Unión Latina and the European Society for Astronomy in Culture, to put into value the cultural heritage related with the observation of the fi rmament. To work jointly with the International Commission on Illumination (CIE) in • order to promote the intelligent use of lighting in all exterior applications. This to be with the aim of minimising both the use of energy and the spread of obtru-sive light into the natural environment, particularly that upwards into the sky.

StarLight 2007


Organizations Committed to Reducing

Light Pollution

Appendix 2

For up-to-date contact details of organizations across the world committed to countering light pollution, the best source is the IDA website. The organizations listed there should be able to give further information on other local groups in their regions. See

www.darksky.org/index.php?option=com_content&view=article&id=476#Europe www.darksky.org/index.php?option=com_content&view=article&id=435

http://www.darksky.org/index.php?option=com_content&view=article&id=476#Europe

http://www.darksky.org/index.php?option=com_content&view=article&id=435


In 1993, the British Astronomical Association’s Campaign for Dark Skies (CfDS) joined forces with the Council for the Protection of Rural England (CPRE) to pro-duce the widely distributed and much quoted booklet Starry Starry Night , exten-sively revised in 2010. Its contents may be of use to anyone seeking to combat both urban and rural light waste, and the bulk of its text is reproduced here.

Human beings have long looked up in awe, on cloudless nights, at the star-strewn heavens. What did our distant ancestors make of it all? They drew the stars into the framework of their lives by creating constellations, fi tting them to their beliefs and myths. They marveled at the ghostly river of light which is the Milky Way, our own galaxy of 200 billion stars seen from within, arching across the sky. The stars, the moving planets, and ephemeral events such as aurorae, comets and meteors, all these have inspired religious beliefs, poetry, music and scienti fi c enquiry. The mys-terious and unreachable vault of the heavens has been a primary stimulus to the human faculties of wonder and discovery.

For countless years, all this has been ours on every clear night. But during the twentieth century, the glory of the night sky was quietly and gradually taken away from most of the world’s people by wasted arti fi cial light. This process continues unabated, and at a rapidly accelerating rate. Satellite images of Earth at night show wasted light-energy from every town and city, along roads, and in rural areas. Even in the countryside, poorly aimed, over-bright fl oodlights and security lamps have stolen the blessed night from humans, and countless other species which have evolved to the rhythm of light and darkness. The day–night cycles, behavior, feeding and mating patterns of bats, birds, glow-worms, moths, and countless other species are disturbed, and millions are killed, by light going where it is not needed.

Starry Starry Night

Appendix 3

224 Appendix 3

What causes the skyglow that has erased our stars? The light we see in the night sky is mostly direct spillage from lamps which have

simply not been designed for the lighting task: their emissions trespass onto neigh-boring areas, and into the sky. They will often be too bright, which adds to glare and skyglow. Light travelling upwards is scattered and re fl ected by ever-present tiny particles and water droplets in the air, even on the clearest nights. The result is a baleful glow in the night sky, now seen from nearly everywhere in the UK. The constellations, aurorae, meteors and the Zodiacal Light, the faint re fl ection from billions of dust particles in the plane of the Solar System, are now things of the past for many of us.

There is no doubt that the spread of public lighting since the mid-1800s has brought great bene fi ts. The quality and ef fi ciency of lamps are continually improved, but the ‘poor relation’ in lighting design is directionality. What the Victorians saw as a blessing has become an environmental blight. Glare, over-lighting and skyglow have tainted the night. Light intrusion into others’ premises is now a major cause of complaints to environmental health of fi cers, and research suggests it is damaging to health. The Clean Neighbourhoods and Environment Act 2005 gives local authori-ties powers to address intrusive light nuisance: but the night sky itself still has no real protection in law.

The stars continue to disappear behind the veil of wasted light, over great cities and smaller towns. Bedrooms are fi lled with light even with curtains closed. Aggressive 500 W fl oodlights turn neighbor against neighbor in both town and countryside, ousting the traditional more modest and welcoming porch light. It is an interesting fact that Britain’s brightest lighthouse, the Longstone on the Farne Islands, has a 1,000 W source, yet many of us, even those who pay lip service to protecting the environment, use half this amount to light our gardens and drives. Another interesting fact: a 100 W bulb left on all night for 1 year releases a quarter of a ton of carbon dioxide, the major greenhouse gas, from the burning of the fossil fuel used to power it.

Little protest is made about wasted light. Is light pollution merely the uncom-fortable cost of progress? Unlike many other forms of pollution, light pollution is reversible. Lights can be shielded or replaced with more appropriate designs, and wattages can be adjusted appropriately. In the words of the Institution of Lighting Engineers: “Light pollution, whether it keeps you awake through a bedroom win-dow or impedes your view of the night sky, is a form of pollution and could be substantially reduced without detriment to the lighting task.”

Can we regain our heritage above? Yes. Visit the websites listed on www.britas-tro.org/dark-skies

Types of Lighting

The earliest practical lights were incandescent tungsten bulbs, still used commonly for domestic purposes. The next development in street lighting was mercury-vapor discharge lamps, which give a blue-white light, but are low ef fi ciency and fairly short life.



225Appendix 3

Many of the glary, over-powered “security” lamps sold nowadays are of the tungsten-halogen type, very inef fi cient and short-lived. Then came low-pressure sodium (SOX), the strong orange light beneath which colors are indistinguishable. It is the most energy-ef fi cient lighting and the lamps have a long life.

High-pressure sodium (SON) started to replace SOX in the late 1970s. The SON lamps are much smaller than SOX, which can be nearly a metre long. SON can therefore be more easily enclosed in a re fl ector that directs the light where it is needed. SON energy ef fi ciency is not as good as SOX but the life is even better.

Today there is a move towards smaller lamps and white light, with better color rendition, though the lifetime may be shorter. Light-emitting diodes (LEDs) are beginning to appear above our streets.

Making a Difference

Here are some tips:

Talk to people about the skyglow issue, stressing energy and money wasted. • What would they think if water mains leaked every few meters? The CfDS does not want to switch off any necessary light; its motto is “the right • amount of light, directed where needed.” Are your local media up to date with the skyglow issue? Do they include sky-• glow in their environmental reporting? Ask neighbors about lighting plans and tell them why you enjoy the night sky. • Politely approach owners of obtrusive lights: they may not know they are caus-• ing a problem. Experience shows that most offenders will take some remedial action. Write to local councilors, council lighting/highway engineers, MPs, MEPs, • sports clubs etc., to ask about their views and lighting policies. If new, less glary lighting is perceived by some to be dimmer, make sure that • they understand the ef fi ciency of modern, better-directed lamps. Not seeing the glare is a good thing. Set a good example by not using over-bright and glary exterior lights on your own premises. We are told that the climate and the environment in general are under threat from • energy waste. Ensure that debate in your area recognizes the contribution that light spillage makes to these problems. Remember that 100-W bulb? If you or any group you belong to has a website, link to the Campaign for Dark • Skies on www.britastro.org/dark-skies Try to forestall poor lighting schemes by studying planning applications and • making sure your council has lighting clauses in its planning and environmental strategies. Help CfDS directly by subscribing to its newsletter, donating to its fi ghting fund, becoming a local of fi cer or distributing its literature.

Remember: ‘broadsides,’ carping criticism and baldly accusing someone of being a polluter are counterproductive strategies. We can reclaim the night sky


226 Appendix 3

through reasoned argument and strength in numbers. Nothing positive comes from light pollution. Everyone wins if it is reduced.

The British Astronomical Association’s Campaign for Dark Skies works to ensure star-quality lighting in the UK. Its network of local of fi cers publicizes the problem, praises good practice and strives to turn poor lighting schemes into more acceptable ones.


Tom Webster is an in fl uential British lighting professional and ILP member. He has taken a great interest in the environmental impacts of lighting, and has summarized, especially for this book, his views on the future of street lighting into the next three decades.

He writes: It is impossible to look to the future of street lighting without a glance into the

past. When the fi rst UK public lighting was installed in Pall Mall, London, in 1807, people were awed by the result. It was seen as “good”, and as with the other scienti fi c discoveries of the nineteenth century it was obvious that “more” would be better. This attitude prevailed through most of the ensuing century, and indeed, I remember frequently coming across it when visiting lighting engineers for the fi rst time several decades ago. One engineer’s comments in particular are worth quoting: “How can I entertain installing your fancy street lights when there are still areas in my authority that still have no lighting at all?”

It was important to him to install as much cheap (and cheap to run, i.e., low-pressure sodium) lighting as possible.

However, attitudes change. With the end of the twentieth century, as a civiliza-tion, we were beginning to realize that rampant technology growth was probably harming our environment, and forecasters were realizing that our contemporary attitudes were unsustainable. This was certainly true among lighting professionals as well. Light pollution was being brought to the industry’s awareness by dark-sky campaigners in the early 1990s, and Dr John Mason of the BAA wrote a de fi nitive paper in 1991. For much of that decade the issue was largely seen as an issue for astronomers and a non-issue for nearly everyone else. However, by the end of the century most lighting engineers had come to realize that change was on the horizon,

The Future of Street Lighting –

A Professional’s View

Appendix 4

228 Appendix 4

that a paradigm shift in attitude would become necessary. But how to tackle the problems?

Once attitudes change it usually does not take long for technology and ingenuity to propose solutions, and the fi rst decade of the new century demonstrated this. More recently the added impetus of global energy prices and global recession has also added weight to the shift we are now seeing in the discipline of street lighting. The paradigm has shifted from “supply lighting wherever there is none” to “supply lighting where and when needed in appropriate quantities.”

However, just because the paradigm has shifted does not mean that the problem has gone away. Far from it. Technology is providing solutions, but these need to be applied and evaluated. So what are the issues and how will they be tackled?

The “where and when needed…” paradigm has three angles to it. Where? This is being tackled with increasingly sophisticated optical systems, from pioneering re fl ectors used by some companies in the last two decades to the precise lighting made possible by modern LED sources. The “when” angle is being tackled by increasingly sophisticated control choices that have moved from the basic on/off options of old-fashioned photoelectric cells to the in fi nitely variable possibilities of remote monitoring systems. With these modern systems it has become possible to adjust the amount of light emitted at any point during the night right down to indi-vidual street lights via simple Internet-borne command protocols. But where will these lead?

To answer this we need to look at the reasons for the lighting in the fi rst place. Essentially these are twofold, amenity and safety. From an amenity perspective it means that the lighting can become varied in our city centers to provide the public with variety, visual stimulation and the ability to relate to their surroundings in an upbeat and positive manner. The value of the ‘night-time pound’ should not be underestimated and the prevalence of visually spectacular lighting is likely to increase as more and more of our urban centers strive to tap into the economic bene fi ts of a 24-h society. However, elsewhere the safety bene fi ts are becoming increasingly eroded both through a better understanding of what works and why, and through alternative safety measures that are becoming more predominant.

For example, the brakes of a modern car will stop a car in a signi fi cantly shorter distance than those of, say, a 1960s car. Therefore the need to have a street lit that far ahead has become reduced (to mention nothing of the increased ef fi ciency of modern headlights). What this will mean is that over the next decade we will see an increasing number of lighting installations either permanently removed or switch-ing over to the more controllable types mentioned before. Conventional high inten-sity discharge (HID) sources such as high-pressure sodium and metal halide will not give up without a struggle, but will become increasingly obsolete against newer more controllable sources such as LEDs. By 30 years hence they will either have become phased out or will be on the short list for removal come the next capital expenditure round for any given authority.

In 30 years’ time I foresee the major problem facing dark skies campaigners regarding lighting in the streets as being from car headlights, and indeed, cam-paigners will be pushing for wide-scale adoption of night vision devices and radar

229Appendix 4

systems for cars, especially if the move towards the 24-h society in our city centers continues.

There will be other emergent technologies but none as directly signi fi cant to lighting per se as the ‘double whammy’ of in fi nite switchability offered by Internet-borne remote monitoring and fl exibility (including instant ‘on/off-ability’) of LEDs. Technologies to watch for in the future will focus on the ability to do without lighting altogether, such as proximity radar systems, whether offered by electromagnetic including non-visible light or acoustic means and other smart systems to do with moving people about from the 24-h cities to and from their dwelling places.

What about the amateur astronomer? The next decade will probably be very positive as we see increasing numbers of switch-offs, mostly as a response to the austere social environment we are currently facing. However, in the next 20–30 years we may well face a night-time environment where major city centers are emitting signi fi cantly more light than now in the later parts of the night and suburbia that is almost completely dark, except for light-emitting traf fi c. The Campaign for Dark Skies will not be over anytime soon.


ILP Guidance Notes

The Institution of Lighting Professionals (see Bibliography) has produced the following guidelines for good lighting control (reproduced with permission). It should be noted that its recommendations (Table 1 ) for permitted upward light do not necessarily concur with those of dark-sky organizations, who see no reason to allow upward light anywhere.

Guidance Notes for the Reduction of Light Pollution

All living things adjust their behavior according to natural light. Man’s invention of arti fi cial light has done much to safeguard and enhance our night-time environ-ment but, if not properly controlled, obtrusive light (commonly referred to as light pollution) can present serious physiological and ecological problems. Light pollu-tion, whether it keeps you awake through a bedroom window or impedes your view of the night sky, is a form of pollution and could be substantially reduced without detriment to the lighting task.

Skyglow, the brightening of the night sky above our towns and cities; glare, the uncomfortable brightness of a light source when viewed against a dark background; and light intrusion, the spilling of light across property boundaries, are all forms of obtrusive light. This is not only a nuisance, it wastes electricity and thereby large sums of money, but more importantly it helps destroy Earth’s fi nite energy resources, resulting in unnecessary emissions of greenhouse gases.

Recommendations for Good Light

Control

Appendix 5

232 Appendix 5

Listed below are some easy ways to reduce the problems of unnecessary, obtrusive light:

[Al] Do not over-light. This is a major cause of light pollution and is a waste of money. There are published standards for most lighting tasks.

[A2] Switch off lights when not required for safety, security or enhancement of the night-time scene. In this respect one can introduce the concept of a curfew, i.e. a period in which more restrictive controls are applied to obtrusive light. In all new developments there is scope for Local Planning Authorities (LPAs) to impose conditions relating to curfew hours in determining planning appli-cations. For instance the LPA may determine that non-essential lighting, such as advertising and decorative fl oodlighting, should be switched off between 23.00 h and dawn. In the case of new non-residential developments LPAs are encouraged to impose such curfews. The attachment of domestic security and decorative lighting to residential buildings often does not require planning permission. However, as the fl oodlights are operational throughout the night, it is considered that the after curfew levels of lighting control shown in Table 1 should be used at all times.

[A3] Use speci fi cally designed lighting equipment that minimizes the upward spread of light near to, or above the horizontal. Care should be taken when selecting luminaires to ensure that the units chosen will reduce spill light and glare to a minimum. The use of luminaires with double-asymmetric beams designed so that the front glazing is kept at, or near parallel to, the surface being lit will assist in the reduction of glare, provided the units are correctly aimed. Similarly, modern well-controlled projector type luminaires, which can be aimed very precisely, can give an excellent cut-off beyond the lit area so reducing spill light and glare.

[A4] Keep glare to a minimum by ensuring that the main beam angle of all lights directed towards any potential observer is kept below 70°. Higher mounting heights allow lower main beam angles, which can assist in reducing glare. In areas with low ambient lighting levels, glare can be very obtrusive and extra care should be taken when positioning and aiming lighting equipment. When lighting vertical structures such as advertising signs, direct light downwards, wherever possible, to illuminate them; not upwards. If there is no alternative to uplighting, then the use of shields, baf fl es and louvers will help reduce spill light around and over the structure to a minimum.

[A5] For road lighting installations, light near to and above the horizontal should be minimised to reduce glare and visual intrusion (Note ULRs in Table 1 ). The use of full horizontal cut-off luminaires installed at 0° uplift will mini-mise visual intrusion within the landscape as well as upward light. However, in many urban locations, luminaires fi tted with a shallow bowl providing good control of light near to and above the horizontal can provide a satisfac-tory solution whilst maximising the spacing of the luminaires.

233Appendix 5

Tabl

e 1

Obt

rusi

ve li

ght l

imita

tions

for

ext

erio

r lig

htin

g in

stal

latio

ns

Env

iron

men

tal

zone

Sk

yglo

w U

LR

(m

ax.%

)

Lig

ht in

to w

indo

ws

E v

[lux

] (1

) So

urce

inte

nsity

I [

kcd]

(2)

B

uild

ing

lum

inan

ce

befo

re c

urfe

w (

3)

Bef

ore

Aft

er

Bef

ore

Aft

er

Ave

rage

M

axim

um

Cur

few

C

urfe

w

Cur

few

C

urfe

w

L[c

d/m

2 ]

L[c

d/m

2 ]

E1

0 2

1 a 0

0 0

0 E

2 2.

5 5

1 20

0.

5 5

10

E3

5.0

10

2 30

1.

0 10

60

E

4 15

.0

25

5 30

2.

5 25

15

0

Not

es

LIG

HT

IN

TO

WIN

DO

WS

– T

hese

val

ues

are

sugg

este

d m

axim

ums

and

need

to ta

ke a

ccou

nt o

f ex

istin

g lig

ht tr

espa

ss a

t the

poi

nt o

f m

easu

rem

ent.

SOU

RC

E I

NT

EN

SIT

Y –

Thi

s ap

plie

s to

eac

h so

urce

in th

e po

tent

ially

obt

rusi

ve d

irec

tion,

out

side

of

the

area

bei

ng li

t. T

he fi

gure

s gi

ven

are

for

gene

ral

guid

ance

onl

y an

d fo

r som

e la

rge

spor

ts li

ghtin

g ap

plic

atio

ns w

ith li

mite

d m

ount

ing

heig

hts,

may

be

dif fi

cult

to a

chie

ve. I

f the

afo

rem

entio

ned

reco

mm

enda

-tio

ns a

re f

ollo

wed

then

it s

houl

d be

pos

sibl

e to

fur

ther

low

er th

ese

fi gur

es.

BU

ILD

ING

LU

MIN

AN

CE

– T

his

shou

ld b

e lim

ited

to a

void

ove

r lig

htin

g, a

nd re

late

to th

e ge

nera

l dis

tric

t bri

ghtn

ess.

In th

is re

fere

nce

build

ing

lum

inan

ce

is a

pplic

able

to b

uild

ings

dir

ectly

illu

min

ated

as

a ni

ght-

time

feat

ure

as a

gain

st th

e ill

umin

atio

n of

a b

uild

ing

caus

ed b

y sp

ill li

ght f

rom

adj

acen

t fl oo

dlig

hts

or fl

oodl

ight

s fi x

ed to

the

build

ing

but u

sed

to li

ght a

n ad

jace

nt a

rea.

W

here

UL

R U

pwar

d L

ight

Rat

io o

f th

e In

stal

latio

n an

d is

the

max

imum

per

mitt

ed p

erce

ntag

e of

lum

inai

re fl

ux f

or th

e to

tal i

nsta

llatio

n th

at g

oes

dire

ctly

in

to th

e sk

y (f

orm

erly

UW

LR

) E

v =

Ver

tical

Illu

min

ance

in L

ux n

orm

al to

gla

zing

I =

Lig

ht I

nten

sity

in c

ande

las

L =

Lum

inan

ce in

can

dela

s pe

r sq

uare

met

er

a Acc

epta

ble

from

pub

lic r

oad

light

ing

inst

alla

tions

ON

LY

234 Appendix 5

Environmental Zones

It is recommended that the Local Planning Authority as part of their Development Plan specify the following environmental zones for exterior lighting control.

Category Examples

E1 Intrinsically dark areas: national parks, areas of outstanding natural beauty, etc. E2 Low district brightness areas: rural or small village locations E3 Medium district brightness areas: small town centers or urban locations E4 High district brightness areas: Town/city centers with high levels of night-time activity

Where an area to be lit lies on the boundary of two zones or can be observed from another zone, the obtrusive light limitation values used should be those applicable to the most rigorous zone.

These limitations may be supplemented by a Local Planning Authority’s own planning guidance for exterior lighting installations and you are therefore recom-mended to check with the Local Planning Authority before designing or installing any exterior lighting.

IDA’s Good Neighbor Practical Guide

Many of us have experienced this scenario: your neighbors have just installed a new spot light on their property. It has a dusk to dawn sensor on it and they are very proud that they are going to be safe now that they have this light. Unfortunately, it’s lighting up your yard and/or shining into your home, and you don’t want that. How do you talk to your neighbor about this situation? Following are the steps approved by the International Dark-Sky Association to educate your neighbor, and by exten-sion your community, about the value of dark sky friendly lighting.

#1. They probably don’t realize the light is bothersome. Always approach people in a friendly, non-threatening way.

Don’t argue. • Be tactful and understanding. • Don’t dismiss their need to feel safe. •

#2. Do your homework and be prepared to address the real issues. No one said this would be easy.

Know the local costs of electricity (cents per KWH). • Know if there is a local lighting control ordinance, and if so, what are the • details. Research quality security lighting in your area by using the IDA FSA light-• ing list.

235Appendix 5

#3. Don’t hesitate to ask them for their advice/opinion in solving the problem. Good will goes a long way.

#4. Use IDA sound bites whenever you can.

Dark sky friendly lighting does not mean dark ground. • If they don’t identify with astronomy talk about the cost/energy savings of • quality lighting. Agree with them that safety is important and dark sky friendly lighting is • safer. Brighter does not mean safer. •

#5. Print off free materials from the IDA Education tab and present this informa-tion to your neighbor. If there are further questions, call us, or email us, together. We will answer!

#6. A lawsuit is never a good option.

Lawsuits are expensive for everyone. • It creates bad feelings between families/neighbors, and you do live in the • area. Moving is equally expensive. •

Safety Issue

The IDA believes that outdoor lighting should provide real security, not just the illusion of safety using bad lighting. Dark sky friendly lighting shines the light on the ground where it is needed, not into the sky where it is not. It uses a lesser watt-age lamp, which decreases harsh shadows for the “bad guys” to hide in. Effective lighting produces uniform coverage of the area; bad lighting can attract criminals by giving them a place to hide.

Safety includes seeing where you are walking and improving your night time driving experience. Fully shielded lighting provides the necessary illumination to see your surroundings, but without the glare to harm your night vision.

Studies have indicated that there is no conclusive correlation between night lighting and crime. Most property crime is still committed during the day, or inside lit buildings. Smart lighting directs the light where you need it, so you don’t have to choose between security and the natural night sky.

Dark sky friendly lighting is capable of using a lesser wattage lamp than tradi-tional lighting. Why is this? Because by shielding the light (no light above the 90° angle), you direct all the light downward, where it is needed. By directing the light you are not wasting energy lighting the sky above you, and hoping for some of it to “fall” to the ground.

Further energy savers include using timers, dimmers, and motion sensors on outdoor lighting. These features allow you to use the light when you need it, not just in case you need it. By each of us decreasing our carbon footprint for outdoor lighting we can save the equivalent of 600 million gallons of gasoline every year.

236 Appendix 5

The Cost Issue

In terms of cost, in today’s economy every little bit helps! Dark sky friendly lighting fi xtures cost no more than traditional outdoor lighting fi xtures. The big difference is you can use less power to run these fi xtures than traditional lamps. Your cost savings on your utility bill will pay for the fi xture within the year. By shielding the fi xture, meaning no light above the 90° angle, a lesser wattage lamp can now be used because you don’t have to light the night as well as your steps. Why pay for light that is not being used? Wasted light at night in the United States alone costs $1.74 billion annually.

The Wildlife Issue

Scientists and researchers are only now beginning to understand the long term effects of too much arti fi cial light at night on all species. As humans expand into more rural areas, our light pollution produces a “continual state of twilight” on the habitats around us. This twilight affects mammals, birds, amphibians, reptiles, and insects. These ill-effects include reduced foraging for food, decreases in reproduc-tion, more predation from daytime creatures, and reduction in natural navigation abilities. This is all preventable!

Sample Letter to Neighbor or Business

Dear XXXXX

Allow me to introduce myself, I am your neighbor (insert name) and I would love to talk to you about good outdoor lighting. I have noticed that you have installed outdoor lights on your property, and I applaud your desire to help improve our neighborhood.

At this time your lights are a bit too bright and they are shining in (pick areas as they apply: our bedroom window, the backyard, into our house etc.), and interferes with our (sleep, hobbies, view of the sky, etc.). I’m sure you weren’t aware of this and I wanted to bring it to your attention as soon as possible to avoid any misun-derstanding. Let me be clear. I am not asking you to remove the lights, but perhaps they can be re-directed onto the ground where they will do the most good. In addi-tion, we could work together to shield the lights so that they are even more effec-tive. Shielding a lamp usually requires a lesser wattage bulb, which is a big money saver within just a year’s time. Who couldn’t use a few money saving tips these days? Shielding reduces glare, which can be blinding and produces less harsh shad-ows where the “bad guys” can hide. Dark sky friendly lighting provides real secu-rity, not just an illusion.

237Appendix 5

There are other ways to save money and still be safe. When lights have motion sensors, they provide an alert if someone is in your yard after dark and they save you money by keeping the lights off when they are not needed. Timers are another money saver because they can turn off your lights when you will not be using the yard, for instance when you retire for the night.

Thank you so much for your time and understanding. I would love to talk with you further about the advantages to using dark sky friendly lighting and how it bene fi ts your safety, your budget, and the night sky.

Sincerely, Your Neighbor

The Cranborne Chase and West Wiltshire Downs Area of Outstanding Natural Beauty Position Statement on Light Pollution (2008)

The Cranborne Chase and West Wiltshire Downs AONB derives much of its beauty from its qualities of tranquility, remoteness and cultural heritage. Light pollution has the potential to erode and destroy that tranquility and sense of remoteness.

It is therefore considered appropriate that all arti fi cial external lighting within its borders or within the setting of the AONB should be muted, screened, and the mini-mum required. To accord with this aim, no external lights should be erected or installed in or within the setting of the AONB unless:

1. They can be shown to be essential for security and safety, and the minimum necessary to achieve it;

2. They are directed downwards and designed or shielded to prevent upward, sideways and outward spillage;

3. They give a light whose color and intensity are appropriate for the wider setting;

4. They do not highlight a structure or feature that would have an adverse visual impact on the surrounding landscape; and

5. They utilize the most energy- and pollution-ef fi cient equipment that is reason-ably available.

In order to meet these aims where existing lighting is identi fi ed as having an adverse effect on the character of the AONB, the AONB Partnership will encourage and facilitate the removal or modi fi cation of the lighting units. Modifying and installing external lighting that meets the above criteria will help to ensure that the AONB’s special character and attractive environment will not be spoiled by sky-glow or intrusive light.


(Reproduced With Permission)

In her article Light Pollution: A Review of the Law (Journal of Planning and Environment Law, January 1998), lawyer Penny Jewkes wrote that: There are sev-eral parallels to be drawn between light pollution and noise, which occupied a simi-larly uncertain territory prior to 1960, when the Noise Abatement Act re fl ected various bylaws used by local authorities to deal with local noise problems. However, it was not until the Control of Pollution Act 1974 that effective and comprehensive controls were introduced. Light has the potential to cause distress and is an equally insidious pollutant. Noise and light are both intangible and ephemeral, yet suscep-tible to measurement; their detrimental effects are relatively easily avoided or stopped and both are closely associated with the development pressures of post-industrial societies. It is the perception of the relative degree, frequency and effect of the problem which causes noise pollution to be more regulated than light pollu-tion, rather than any technological differences.

There is signi fi cant capacity within the planning system to in fl uence the design and installation of lighting schemes, but it has a limited ability to control the prob-lems caused by poor lighting which is unrelated to new development. Development plans and supplementary planning guidance may regulate the lighting consider-ations arising out of any new proposals, but the development control process is constrained by the fundamental problem that many of the lighting installations that cause this form of pollution fall outside its statutory scope.

Planning permission is usually required for the carrying out of any ‘develop-ment’ of land. As is well known, this can take two forms, namely ‘the carrying out

Extracts from Articles on the Legal Aspect of Light Pollution

Appendix 6

240 Appendix 6

of buildings, engineering, mining or other operations, in, on, over or under land.’ It is a question of fact in each case whether a lighting installation amounts to a build-ing or an engineering operation. These terms are given their ordinary meaning although the courts have said that engineering operations are usually those under-taken by engineers, which would include specialist lighting engineers. Large scale installations, such as the lighting of a football stadium or public tennis courts, are clearly a form of development which comes within the statutory de fi nition. More dif fi cult, however, is the smaller scale lighting installation, which is probably out-side planning control unless it materially affects the external appearance of a build-ing. This quali fi cation has to be interpreted in the light of the individual case.

The impact of lighting on amenity and on the environment are material consid-erations in the decision-making process… As a general rule, local planning authori-ties are not encouraged to duplicate controls imposed by other statutory bodies (such as the Environment Agency). But environmental considerations are material, and, since light pollution is not speci fi cally controlled under any other legislation, the problem of duplication of control does not arise. The protection of a group of individual interests, such as disturbance to neighbors, is an aspect of the public interest and capable of being a planning consideration.

Light is not speci fi cally included in the list of potential nuisances ( Author’s note: this was written before the CNE Act lighting clause mentioned in Chap. 3 came into effect ). Nevertheless, some local authorities have served abatement notices under Section 80 in respect of light nuisances. It is debatable whether such a course would survive a challenge on appeal, although it might be possible to argue, in appropriate circumstances, that intense building luminance amounted to ‘premises in such a state as to be a nuisance.’

The common law action for nuisance is the most common method of asserting an environmental claim. Nuisance takes two forms: public and private. a private nui-sance arises from a substantial interference with an individual’s use and enjoyment of his property, and an action can only be pursued by the individual whose rights have been affected…. A public nuisance is one ‘which materially affects the reason-able comfort and convenience of a class of Her Majesty’s subjects.’ This tort shares many of the characteristics of private nuisance. However, a public nuisance is a criminal offence and the action may be brought by the Attorney General (or the Local Authority). An individual may also bring proceedings if he has suffered some special damage over and above that suffered by the general public. Where fl oodlights from a sports stadium affect a large number of people living in an area, and have a particularly detrimental effect on adjacent landowners, the complainants may have an action in private and public nuisance. This type of action, in which excessive lighting is alleged, requires the courts to effect a delicate balancing exercise between neighbours’ competing uses of land. The court will take numerous factors into account, such as the locality where the complaint has arisen, how often the activity occurs, whether one neighbour is more sensitive than normal and whether the other party has a good reason for carrying out the activity complained of.

http://dx.doi.org/10.1007/978-1-4614-3822-9_3

241Appendix 6

Conclusion

Light pollution is a relatively newly identi fi ed environmental problem and in some of its manifestations it may appear to be a relatively insigni fi cant issue. But insigni fi cant to whom?

A person who is unable to sleep because of his neighbor’s security light may not regard this as a minor problem. He may be perplexed by the logic which says that if his neighbor’s dog keeps him awake at night the local authority environmental health of fi cer has powers to intervene on his behalf, but he cannot do so if the insomnia is caused by glaring lights. A sensitively designed development may be absorbed into a rural scene without detriment to visual amenity and be acceptable to local people. The position might be quite different when they see it lit up at night. We want our children to inherit a planet rich with diverse species and plantlife; is it any less important that they should be able to see the Milky Way or the tail of the Hale-Bopp comet? Does it make any difference whether the survival of a rare insect is jeopardized by a light source or by a pesticide? These are some of the many ques-tions which the problem of light pollution raises and which are only in part addressed by the existing regulations.”

In his article “And God Divided the Light from the Darkness” – Has Humanity Mixed Them Up Again? ( Environmental Law and Management , January 1997), law lecturer Martin Morgan-Taylor wrote: “The increase in national and local authority maintained night lighting is arguably treating the symptoms of the societal disease which manifests itself as crime: for example, increasing lighting because there is an increase in crime. The money spent on reducing the fear of crime, and on giving the impression that money is being spent on run-down areas, could be put to much better use by fi ghting crime at its roots…. The second matter usually cited to defend the general increase in lighting is safety. It must be accepted that without lighting, the world would not be safe at night. However, a balance is what is needed, not an abso-lute fl ood of lighting for lighting’s sake…. the American ‘Green Lights’ program, launched in 1993, is a government backed movement to replace light fi ttings both public and commercial with fi ttings which are more economical and less ecologically harmful. The aim is to cut energy bills for participants, and reduce global environ-mental impact. The Environmental Protection Agency estimates that if ‘green lights’ were implemented on all participants’ land, $16 billion would be saved. This equates to 12% of U.S. utility carbon/sulphur/nitrogen dioxide emissions.

“It is proposed that there are solutions to the lighting problem. Firstly, there should be some form of legislation which restricts power consumption and output of domestic exterior fl oodlighting. There is no positive gain to be had by installing a 500 W light in a small back yard, but there are disadvantages, both to the environ-ment and to neighbours. All light fi ttings should be properly designed, perhaps to a BS standard, so that they may point straight down and still permit the functioning of a trigger mechanism. Instructions for their installation should counsel the installer to angle the light sensibly, so that a burglar may be seen by a passer-by

242 Appendix 6

who will not be dazzled, and so as not to interfere with neighbours. Environmental health departments should be granted the authority to order the repositioning of poorly placed lights that interfere with neighbours or pose a risk to road traf fi c. Should a person not comply, then local authorities should have the power to remove the light fi tting, or where the offender has been malicious or uncompliant, to prosecute… maintaining safe levels of night-time lighting, with the intention of reducing environmental harm…such a policy will reduce the emission of green-house gases and also help protect the environment. It is argued that this time has now come.”


1. THE MORE LIGHT THE BETTER: “The more light the better” is the same type of reasoning as saying the more salt on your food the better, or the more fertilizer the better, or the more medicine the better. Obviously, there comes a point where you can have too much of a good thing. Eventually, it becomes wasteful or even harmful. Night-time lighting is that way. We need well-lit streets, security lighting, and parking lot lighting. However, we do not need glare, clutter, confusion, light trespass, light pollution, and energy waste. Excessively bright, numerous, unshielded lights cause all of these things.

The amount of light you need depends upon the task. For example, you use low wattage colored bulbs for Christmas tree lights, and perhaps a 60 W bulb for a porch light. If more light is better, why are night lights in a bedroom dim instead of bright? The next time you are at an airport at night look at the brightness of the taxi lights (blue color) or the runway lights (white color). They are relatively dim so as to not harm the pilot’s night vision and cause confusion. Even the rotating airport beacon is not especially bright. The strobe lights on tall chimneys and radio towers are of low wattage, yet they are visible for miles. Those who claim “the more light the better” often are salespeople or manufacturers who pander to people’s misconceptions to make a quick sale rather than educate their customers about truly effective and environmentally responsible lighting.

2. LIGHT POLLUTION ONLY AFFECTS ASTRONOMERS: Light pollution affects all of us. It robs the professional astronomer of his or her livelihood and hinders the amateur’s enjoyment of their hobby. It deprives us all of one of nature’s grandest wonders – the night sky. Many persons who claim this is of no importance have never gone far out of town to see what they are missing. Those who grow up in an urban environment may never see the Milky Way. How can some-one miss something he has never seen? The loss of this part of nature desensitizes

Some Lighting Myths

(Reproduced by kind permission of

Dr. David Crawford, IDA)

Appendix 7

244 Appendix 7

us to other insults upon the environment. This is like saying the loss of a virgin forest is of no concern because most people won’t get to see it anyway, and there are plenty of trees for lumber. The loss of wild fl owers, polar bears, wolves, whales, and other threatened species, to be honest, won’t affect the average per-son. Their loss only directly impacts biologists, or those more in tune with the natural environment than in the environment we humans create. After all, humans have done very well without mammoths, mastodons, and passenger pigeons. However, no one supports the extinction of magni fi cent animals. Why should we permit the loss of our skies? Not only does light pollution dim the stars for the astronomer, but it dims them for all persons. Everyone has a right to the stars.

Light pollution takes away one of our most ancient heritages and it represents visible destruction of the environment in several ways: the dome of light hanging over most cities blots out the stars; electricity is generated and wasted to light the night sky – light needs to be on the ground not up in the sky; the wasted electricity represents wasteful burning of coal, oil, and natural gas; the by-products of these wasteful burnings show up as acid rain, smoke, and carbon dioxide emission; strip mining and underground mines ravish the land to produce the coal for the wasteful burnings; runoffs from this mining pollutes rivers and streams. Thus, light pollu-tion does far more than inconvenience a few astronomers. It is a most harmful assault upon our environment. It affects us all, and all of us ought to be concerned about it.

3. JUST GO OUT OF TOWN AWAY FROM THE LIGHTS: This is equivalent to saying why worry about the loss of trees and fl owers in our cities. Why have urban parks? Just go out of town to see some grass, fl owers, or trees. It shouldn’t be necessary to go out of town to see these. If we can’t have enough sense to plant trees, shrubs, and fl owers all around our cities, we can at least have enough sense to plan for parks and preserve those green areas left. Why not have the same atti-tude toward dark skies? We are not asking people to turn off their lights. We are asking them to shield the lights, use proper wattage for the task, and turn off unneeded lights. In any event, it is no simple task to get away from the lights. Urban sky glow, the dome of light hanging over all cities of any substantial size, extends for miles and miles. For example, it easy to see the sky glow of Phoenix, Arizona, from more than 100 miles away. The sky glow from Los Angeles, California, is visible from an airplane 200 miles away. How many dark spots are left in the urban corridor in the North-eastern part of the United States? Even in the most remote portions of North America, there are dusk-to-dawn lights blaring into the darkness. The light from even one of these causes signi fi cant light tres-pass a mile or more away. I challenge anyone reading this to fi nd a mountain top or plateau in the continental United States where there is no trace of light pollu-tion visible somewhere on the horizon.

4. IT’S TOO LATE TO DO ANYTHING ABOUT LIGHT POLLUTION: THERE ARE TOO MANY LIGHTS: This is a frequent response when I ask people why they are not more active in the light pollution struggle. It’s a tough response to adequately address. Yes, the problem is enormous, growing in many areas, and

245Appendix 7

very dif fi cult to grasp fully. This doesn’t mean it isn’t worthy of effort. We have barely begun to fi ght. Just because we have a very big problem on our hands and presently few resources to bring to bear, doesn’t mean we can’t ultimately win. It’s way too early in the struggle to say it’s impossible to do anything about light pollution. Only recently has a small fraction of the public and astronomical com-munity awakened to the problem. Only recently have we realized there are solu-tions to most lighting dif fi culties. There are now excellent fi xtures available for all lighting needs. This is one of those few problems whose solution is eminently sensible, available, and which saves money in both the short term and the long haul. If you expect to rid a city of its sky glow in the next year, then you will be very disappointed. If you want to get rid of local sources of light trespass, such as a dusk-to dawn light next door or an unshielded street light on the corner, then you have a very good chance of accomplishing your goals with persistent but not obnoxious effort. You also have a reasonable chance for changing laws and insti-tuting proper lighting techniques in your community. Over a long period good lights will replace the bad and the ugly ones. There will be a gradual slowing of the loss of dark skies and then an actual darkening of the sky in some areas. This will not happen quickly but it is possible. It will take incredible amounts of work and determination but it can be done.

5. LOW PRESSURE SODIUM (LPS) CAUSES HEADACHES: This is just one of hundreds of ill-founded rumors about LPS lighting. Low pressure sodium is the most energy ef fi cient lighting available. LPS is favored by professional astrono-mers because it is an essentially monochromatic light source, more easily fi ltered out than other light sources. It produces a bright, yellow light to which the eye is very sensitive. Therefore, it is very good for street lights, parking lot lighting, and security lighting. Ask those in San Diego, San Jose, Long Beach, and Glendale, Arizona, where LPS is used extensively. Why isn’t it used more often? The answer is complex. Several large lighting manufacturers do not make LPS fi xtures or bulbs and campaign against it. It has no color rendition, which bothers many persons, especially when they fi rst see it, and it should not be used for any lighting application that needs good color. LPS fi xtures and ballasts are expen-sive and not readily available, even though LPS use quickly saves money. LPS lighting does not produce headaches any more than any other type of outdoor lighting. In fact, it tends to produce less glare than mercury vapor lights or high pressure sodium (HPS) lights and is thus probably less likely to give headaches. LPS bulbs are no more dangerous to dispose of than any other type of light bulbs. In fact, consider the toxic substances that are found in other bulbs. Mercury vapor lights contain mercury. In the metallic form, mercury is not especially toxic but many of its salts are quite poisonous. HPS bulbs contain metallic sodium just like LPS bulbs; therefore, they have the same disposal problems as the LPS bulbs, mainly the metallic sodium which is highly reactive. If HPS or LPS bulbs are carefully broken under water, the sodium reacts with the water to give sodium hydroxide, everyday lye, the same substance as in drain cleaners. How about all the glass? Well, this is a problem with disposing of any light bulb. Metal halide bulbs contain all sorts of toxic metallic salts. The bottom line is that

246 Appendix 7

the disposal of a large number of light bulbs is an environmental problem no matter what the bulb type.

6. SECURITY LIGHTS PREVENT CRIME: Does outdoor night-time lighting prevent crime? The answer is: nobody knows. In some cases, lighting seems to deter crime and it makes people feel more secure, but in reality they may be just as secure without the lighting. In some cases, lighting probably increases crime because it draws attention to a house or business that would otherwise escape attention. Most crimes, violent and otherwise, take place during the day. After all, criminals need light to do their work, too. A dusk-to dawn light shining all night in a rural area probably is an inducement for robbery and vandalism. A passer-by might not otherwise notice that the farmhouse is even there. An infrared motion-sensor security light which comes on only when someone steps into the beam makes a lot of sense. It is only on when needed, thereby conserving energy. Its sudden illumination serves to frighten away the criminal. These lights are now beginning to replace some of the all-night dusk-to-dawn 175 W mercury vapor lights. This makes good sense from the economic, environmental, and crime prevention points of view. The motion-sensor security lights can cause light pollution and light trespass if too high a wattage spotlight is used, or if they are not aimed down toward the ground. They should also have some shielding. Do street lights, parking lot lights, and security lights prevent crime? Maybe yes, maybe no. If they are overly bright with much glare, they actually make it easier for a criminal to hide in the deep shadows produced by objects in the harsh glary light and encourage crime rather than discourage it. Well-lit streets with even, uniform lighting, low glare, and utilizing fully-shielded fi xtures probably have lower vehicle and pedestrian accident rates. How about bright lights in a parking lot? How many people do you know whose car has been broken into during the day, or while directly underneath a light at night? One speaker at a recent lighting symposium recounted how his car was robbed at a local mall. It sat near a store entrance and was directly under a bright light! There are simply no good scienti fi c studies that convincingly show the relationship between lighting and crime. Our cities are far more brightly lit than ever. Yet, the crime rate soars. Maybe lights directly lead to crime. Who knows? One study at a small eastern college showed almost all violent night-time crimes took place in well-lit places. This study, while informative, cannot be generalized to other locales because of the some-what unique nature of the college and the college town. Crime is a very complex sociological phenomenon controlled by many factors, and it will vary consider-ably from place to place. My own personal opinion is that crime is little affected by night-time lighting for better or worse. Main arterial streets should be well lit to reduce automobile and pedestrian accidents. Busy malls should have good lighting to reduce accidents and perhaps deter crime. After business hours this lighting can be reduced or even turned off. Security lighting can be at a relatively low level. This saves money, and not much light is needed to fi nd your way to a door or fi nd your way out to your car. Not much light is needed to see a suspi-cious-looking person loitering around. No matter what the lighting situation, the proper wattage, not overkill, should be used, and all light should come from

247Appendix 7

full-cut-off, shielded fi xtures. Low pressure sodium lighting is ideal for many of these applications because of its very low operating cost.

7. ONLY ASTRONOMERS CARE ABOUT LIGHT POLLUTION (THOSE PERSONS FIGHTING LIGHT POLLUTION ARE JUST CRAZY IDIOTS): Anyone who takes a well-educated and reasoned approach toward environmen-tal or quality of life issues is not a “crazy idiot.” We (and many others as well) are concerned about light pollution, light trespass, radio pollution, and space debris. After all, the night sky is part of everyone’s environment, enormous amounts of energy are wasted lighting the night sky, radio astronomers have to struggle to fi nd usable portions of the electromagnetic spectrum for their work, and space debris is a rapidly growing problem for spacecraft (and people) in orbit. Why should someone be considered a nut because he or she is concerned about the environment? However, persons involved in environmental causes must carefully de fi ne the problem they want to solve, learn the facts, appreciate the legitimate perspective of their opponents, and offer people solutions rather than complaints. This is IDA’s philosophy and modus operandi. Light and radio pollution are solvable problems if the facts are properly conveyed to the public. Light pollution is the one form of pollution whose solution immediately saves money. Not just astronomers care about light pollution and light trespass. IDA’s Board of Directors consists of a physician, a lawyer, two lighting designers, a city street lighting director, as well as professional and amateur astronomers. Many IDA members are not astronomers or even particularly interested in astronomy. They are concerned about energy conservation, preservation of our environment, and proper night-time outdoor lighting. They include homemakers, scientists, lawyers, pilots, doctors, engineers, retired persons, and so forth. Much of IDA’s strongest support comes from professional lighting engineers, lighting suppliers, and lighting manufacturers.


IDA’s standard letter informs and suggests courses of action:

Dear … ,

Here is an environmental issue you might not have heard of yet: Light Pollution. It is a growing threat to our night-time environment, one that has already seriously harmed astronomers, both amateurs and professionals. We are faced with the dis-tinct possibility that in only a generation or two very few people will be able to have a “live” view of the universe. Urban sky glow will have blotted out the dark sky, just as a lighted room blots out the view of a slide show.

Components of light pollution include:

1. Urban Sky Glow: it is destroying humanity’s view of the universe. 2. Glare: blinding us and harming visibility; Glare is never good. 3. Light Trespass: someone’s outdoor lights offending us, “trespassing” on our

property. 4. Clutter: trashing the night-time environment, and causing confusion as well. 5. Energy Waste: wasted light costs over one billion dollars a year, in the United

States alone.

There are solutions to all of these problems. Quality lighting is the key. These solu-tions preserve the dark skies, improve the quality of the night-time lighting and the night-time environment, and save money as well. It is a Win/Win/Win situation.

Awareness of the problem and of the solutions is needed, of course, but is often lacking, even among lighting professionals. Lack of awareness (rather than resis-tance) is the main problem in implementing these solutions.

Advice from IDA and CfDS

Appendix 8

250 Appendix 8

You can help. Please do. Here’s how: First, become aware. Insist on quality lighting. Use it yourself. Quality lighting

is well shielded (so the light is used, not wasted), uses the right amount of light (not overkill), includes time controls when possible, and includes the use of low pres-sure sodium (LPS) as the light source when possible. (LPS is the most cost-effective light source, excellent where color rendering is not critical.) Quality light is directed downward where it is needed, not up or sideways where it is wasted and causes glare, light trespass, and bright skies.

Second, a non-pro fi t organization, the International Dark-Sky Association (IDA), is very active in raising awareness of the issues and in pushing for solutions to the problem. The IDA also addresses the related issues of radio interference, space debris, and other environmental threats to our view of the universe. All of these problems adversely affect the general public and seriously threaten the future of frontier astronomical research everywhere on Earth.

(Included are several sheets which discuss this issue in greater detail.) I hope you will take the time to read them, and to think about the issue. The IDA, and all who care about the environment and our quality of life, need your help. Please become aware of wasteful lighting, and do what you can to help.

Sincerely yours, Etc.

CfDS sends the following advice to people seeking guidance on countering prob-lems caused by stray light:

If writing to your council, and in spreading awareness about sane lighting, you might consider the following options:

1. Find out who is responsible for lighting. If “A” class roads are lit, it is normally the Highways Agency; minor roads and side streets are normally lit by the county or district council. All councils will have a lighting engineer, and (s)he should be following the guidelines of the Institution of Lighting Professionals (ILP), which recommend minimal upward light. All major lighting companies, dozens of local councils, the Institute of Environmental Health Of fi cers, the Campaign to Protect Rural England (CPRE – joint producers with the BAA of the Starry Starry Night lea fl et), and many other bodies agree with the BAA/CfDS and the ILP that light pollution is a problem to be confronted. Anyone installing glary road lights with upward waste light is simply behind the times and not environmentally aware;

2. Refer your lighting engineer(s) to the ILP, and also to the many lighting fi rms now producing full-cut-off and semi-cut-off lamps. With the latter, there should still be minimal upward light (what lighting people call Upward Waste Light Ratio [UWLR]).

3. Tell friends and neighbors about light pollution, using CfDS material. An astron-omer in a nearby back garden at night is a far more effective security device than any number of 500 W lights! Try to let everybody (local press?) know that the environment above is just as valuable to the human spirit as that below. Get your local environmentalists involved: the CPRE, for example, has produced a “light

251Appendix 8

pollution charter”, and declares itself fi rmly committed to eradicating local light pollution;

4. Resist arguments such as: “it’s not the lights shining upwards. It’s mostly re fl ection off the ground” – anyone standing on a hill over a large conurbation can see with their own eyes that it is the lamps which are glowing brightly, not the ground! Or “cut-off lights are more expensive” – they may be, but what price the environment? The trend is towards environmentally friendly lighting, and councils with glary lights may well have to replace them with something better in the near future. Why not do it now and save money later? Or “you need more lights with FCOs as they have to be spaced more closely together” – no they don’t. The local street lights in the CfDS coordinator’s area have now been replaced with FCO and SCO designs. The night sky is much improved (which further refutes the ground re fl ection argument) and they are on exactly the same columns as the old, wasteful lights. The M5 motorway was recently relit with FCOs – four FCOs for every fi ve old, glary lights, so they are actually now fur-ther apart. It’s column height and the optical re fl ectors in the lamps which con-trol the light spread, not the distance between them. Or “lights have got to be bright to defeat crime” – there is no proof that light and crime are related. Some studies show a reduction in crime where lighting has been introduced or upgraded. Other studies show the opposite, or no change. The vast amount of crime which takes place in broad daylight suggests that ambient light levels do not deter crim-inals. The best friend of the modern burglar is the sideways-pointing 500-W “security” light, which emits a dazzling glare behind which he can work unseen.

CfDS wishes you success in spreading the message that effective lighting and an attractive natural night-time environment are not mutually exclusive.


Guidelines issued by national governments for the reduction of light pollution are few; for example, I have been unable to discover any American governmental agency guidelines on good lighting (if any appear, the IDA website will undoubt-edly feature them). The fi rst such advice was probably that contained in the docu-ment Lighting in the Countryside – Towards Good Practice (ISBN 0 11 753391), issued by the British government’s Department of the Environment in 1997, in col-laboration with the UK Countryside Commission and with input from CfDS, CPRE, ILP and the Royal Fine Arts Commission. Though restricting its brief to rural lighting, this 80-page guide contains advice on all its aspects. In its section on ‘Action on Lighting in the Countryside’ we read:

Lighting in itself is not a problem; it only becomes a problem where it is excessive, poorly designed or badly installed. Better use of the planning system to in fl uence lighting propos-als; better awareness of the potential adverse impacts of light amongst developers, manu-facturers, retailers and the general public; and improved lighting design and landscape design are among the most important ways of tackling issues of overlighting…. For all but the simplest lighting scheme, professional advice whether from the lighting manufacturer or from a quali fi ed lighting engineer/designer, is recommended. The range of lighting standards and lighting products on the market today is very broad…. If action on lighting in the countryside is to be effective it will require the close co-operation and participation of all those involved in planning, designing, and installing lighting schemes. The respon-sibility for tackling lighting issues is very much a shared one …. Local authority planners should recognize the cumulative impacts of lighting on countryside character, and be more pro-active. They should consider the need for policies on lighting in the development plan …. Developers should look differently upon lighting than they did in the past, and should not automatically assume that it is a good thing. This implies a more critical assessment of lighting need and alternatives, and a greater willingness to consider the removal or upgrad-ing of intrusive lighting. In judging the costs of lighting they should take a long term view and give due weight to energy and maintenance costs as well as capital costs …. Lighting

Examples of Governmental

Guidelines on Good Lighting Practice

Appendix 9

254 Appendix 9

engineers and designers should adopt a more structured approach to assessing the environ-mental impacts of lighting installations …. Manufacturers and suppliers of lighting equip-ment should provide a design service that is as impartial and responsible as possible, and should focus increasingly on high quality lighting products …. In relation to security light-ing that is intended for DIY installation, retailers have a special responsibility to ensure that good information is available on how to choose appropriate equipment, minimize light levels, and control light pollution through good installation …. Lastly, members of the public have a vital rôle in the control of light pollution. They are responsible not only for most domestic security lighting, but also for much of the small scale lighting on commer-cial and business premises that does not need planning permission. They should take great care in the selection and installation of lighting equipment, and if in doubt, should always seek professional advice.

(Crown copyright is reproduced with the permission of the Controller of Her Majesty’s Stationery Of fi ce).

In 1998, the Environment Agency of Japan, in collaboration with the CIE Japanese section, published its Guidelines for Light Pollution : Aiming for Good Lighting Environments . In his introduction to this minutely detailed 93-page docu-ment, Syuzo Isobe, of the National Astronomical Observatory at Mitaka, Tokyo, describes the necessity for the intervention of lighting engineers on a larger scale, good monitoring and the increased use of satellite technology in the measurement of wasted energy. The document recommends close inspection of proposed lighting by the use of standardized checking procedures for all lighting tasks, and lists procedures to be undertaken. In the body of the text, we read:

Checklist for outdoor lighting:

Targets: facility maintenance companies, facility managers, designers of environmental lighting, and citizens.

When installing lighting that takes into consideration the lighting environment … Studies for suf fi cient and ef fi cient lighting are necessary. For these studies, it is important to clearly identify the objectives for each individual lighting installation, and this is related to the suppression of spill light or obtrusive light, and attaining a more ef fi cient lighting facility.

Check procedure:

Preparation of an ‘overall lighting plan’:

(1) Understanding the type of facility (e.g. residential, business, public); (2) Selection of lighting group (type of function, e.g. transit, crime prevention, decorative); (3) Understanding the surrounding environment; (4) Arrangement of compatibility of lighting groups; (5) Preparation of ‘overall check sheet’ and ‘lighting group arrangement plan’.

(Reproduced by kind permission of Syuzo Isobe)


“Simple Guidelines for Lighting Regulations for Small Communities, Urban Neighborhoods,

and Subdivisions”

The Purpose of the Regulation Is To

Permit reasonable uses of outdoor lighting for night-time safety, utility, security, • and enjoyment while preserving the ambiance of the night; Curtail and reverse any degradation of the night-time visual environment and the • night sky; Minimize glare and obtrusive light by limiting outdoor lighting that is misdi-• rected, excessive, or unnecessary; Conserve energy and resources to the greatest extent possible; • Help protect the natural environment from the damaging effects of night • lighting.

All outdoor lighting fi xtures (luminaires) shall be installed in conformance with this Regulation and with the provisions of the Building Code, the Electrical Code, and the Sign Code, as applicable and under permit and inspection, if such is required.

The IDA’s

Appendix 10

256 Appendix 10

Comment: Practical Considerations

1. The idea that more light always results in better safety and security is a myth. One needs only the right amount of light, in the right place, at the right time. More light often means wasted light and energy.

2. Use the lowest wattage of lamp that is feasible. The maximum wattage for most commercial applications should be 250 W of high intensity discharge lighting should be considered the maximum, but less is usually suf fi cient.

3. Whenever possible, turn off the lights or use motion sensor controlled lighting. 4. Incorporate curfews (i.e. turn lights off automatically after a certain hour when

businesses close or traf fi c is minimal). This is an easy and fast way to initiate dark sky practices.

Maximum Lamp Wattage and Required Luminaire or Lamp Shielding

All lighting installations shall be designed and installed to be fully shielded (full cut-off), except as in exceptions below, and shall have a maximum lamp wattage of 250 W HID (or lumen equivalent) for commercial lighting, 100 W incandescent, and 26 W compact fl uorescent for residential lighting (or approximately 1,600 lumens). In residential areas, light should be shielded such that the lamp itself or the lamp image is not directly visible outside the property perimeter.

Lighting That Is Exempt from These Regulations

1. Lighting in swimming pools and other water features governed by Article 680 of the National Electrical Code.

2. Exit signs and other illumination required by building codes. 3. Lighting for stairs and ramps, as required by the building code. 4. Signs are regulated by the sign code, but all sign lighting is recommended to be

fully shielded. 5. Holiday and temporary lighting (less than 30 days use in any 1 year). 6. Football, baseball, and softball fi eld lighting; only with permit from the authority

recognizing that steps have been taken to minimize glare and light trespass, and utilize sensible curfews.

7. Low voltage landscape lighting, but such lighting should be shielded in such a way as to eliminate glare and light trespass.

257Appendix 10

Additional Requirements

Lighting attached to single-family home structures should not exceed the height • of the eave. Residential pole height restrictions can be considered to control light trespass on • adjacent properties.

Notes

1. The general belief that more light means better safety and security is just a myth. All that is needed is the right amount, in the right place, at the right time. More light just means wasted light and energy.

2. Use the lowest wattage of lamp as possible. For cost saving purposes, consider compact fl uorescent lamps rather than incandescent, as they use much less energy and have a much longer lifetime.

3. Whenever possible, turn off the lights.


The complete document is available as Information Sheet 91 on the IDA website (see Bibliography). Reproduced with permission.

Ordinance No. 8210. Tucson/Pima County Outdoor Lighting Code, 21 March 1994.

Section 1

Purpose and Intent. The purpose of this Code is to provide standards for outdoor lighting so that its use does not unreasonably interfere with astronomical observa-tions. It is the intent of this Code to encourage, through the regulation of the types, kinds, construction, installation, and uses of outdoor electrically powered illuminat-ing devices, lighting practices and systems … (conservation of) energy without decreasing safety, utility, security, and productivity while enhancing nighttime enjoyment of property within the jurisdiction.

Section 2

…All outdoor electrically powered illuminating devices shall be installed in con-formance with the provisions of this Code, the Building Code, the Electrical Code, and the Sign Code of the jurisdiction as applicable and under appropriate permit and inspection.

Extracts from the Revised Tucson and

Pima County Outdoor Lighting

Control Ordinances

Appendix 11

260 Appendix 11

Section 4 De fi nitions

…Section 4.3. “Outdoor light fi xture” means outdoor electrically powered illuminating devices, outdoor lighting or re fl ective surfaces, lamps and similar devices, perma-nently installed or portable, used for illumination or advertisement. Such devices shall include, but are not limited to search, spot, and fl ood lights for:

(1) buildings and structures; (2) recreational areas; (3) parking lot lighting; (4) landscape lighting; (5) billboards and other signs (advertising or other); (6) street light-ing; (7) product display area lighting; (8) building overhangs and open canopies.

Section 5 Shielding

All nonexempt outdoor lighting fi xtures shall have shielding as required by Table 2 of this Code.

…Section 5.1. “Fully shielded” means outdoor light fi xtures shielded or constructed so that no light rays are emitted by the installed fi xture at angles above the horizon-tal plane as certi fi ed by a photometric test report.

…Section 5.2. “Partially shielded” means outdoor light fi xtures shielded or con-structed so that no more than 10% of the light rays are emitted by the installed fi xture at angles above the horizontal plane as certi fi ed by a photometric test report.

Section 9 Prohibitions

…Section 9.1. Mercury Vapor Lamps Fixtures and Lamps. The installation, sale, offer for sale, lease or purchase of any mercury vapor fi xture or lamp for use as outdoor lighting is prohibited.

…Section 9.2. Certain Other Fixtures and Lamps. The installation, sale, offering for sale, lease or purchase of any low pressure sodium, high pressure sodium, metal halide, fl uorescent, quartz or incandescent outdoor lighting fi xture or lamp the use of which is not allowed by Table is prohibited.

…Section 9.3. Laser Source Light. Except as provided in minor Section 9.4, the use of laser source light or any similar high intensity light for outdoor advertising or entertainment, when projected above the horizontal is prohibited.

Section 9.4. Searchlights. The operation of searchlights for advertising purposes is prohibited in Area A and is prohibited in unincorporated Pima County. In the ter-ritorial limits of the City of Tucson, the operation of searchlights for advertising purposes is prohibited in Area A and is prohibited in Area B between 10:00 p.m. and sunrise the following morning.

261Appendix 11

Section 10 Special Uses

Section 10.1. Recreational Facilities. Any light source permitted by this Code may be used for lighting of outdoor recreational facilities (public or private), such as, but not limited to, football fi elds, soccer fi elds, baseball fi elds, softball fi elds, tennis courts, auto race tracks, horse race tracks or show areas, provided all of the follow-ing conditions are met:

(a) Lighting for parking lots and other areas surrounding the playing fi eld, court, or track shall comply with this Code for lighting in the speci fi c Area as de fi ned in Sections 4.4 and 4.5 of this Code.

Table 2 Shielding requirements (area A: 35 miles around Kitt Peak National Observatory, 25 miles around Mount Hopkins Observatory; area B: all area outside area A outside limits of Indian reservations – BM)

Area A Area B

Fixture lamp type Shielded Shielded Low pressure sodium a Partially Partially High pressure sodium Prohibited except fully shielded on arterial streets

and collector streets of 100 ft or more in right of way width.

Fully

Metal halide Prohibited b Fully c, d Fluorescent Fully e, f Fully e, f Quartz g Prohibited Fully Incandescent greater than

160 W Fully Fully

Incandescent 160 W or less None None Any light source of 50 W or

less None None

Glass tubes fi lled with neon, argon, krypton

None None

Other sources As approved by the Building Of fi cial

a This is the preferred light source to minimize undesirable light emission into the night sky affecting astronomical observations. Fully shielded fi xtures are preferred but not required. b Fully shielded and installed metal halide fi xtures shall be allowed for applications where the designing engineer deems that color rendering is critical. c Metal halide lighting, used primarily for display purposes, shall not be used for security lighting after 11:00 pm or after closing hours if before 11:00 pm. Metal halide lamps shall be installed only in enclosed luminaires. d For fi ltering requirements for metal halide fi xture lamp types see Section 6. e Outdoor advertising signs of the type constructed of translucent materials and wholly illumi-nated from within do not require shielding. Dark backgrounds with light lettering or symbols are preferred, to minimize detrimental effects. Unless conforming to the above dark background preference, total lamp wattage per property shall be less than 41 W in Area A. f Warm white and natural lamps are preferred to minimize detrimental effects. g For the purposes of this Code, quartz lamps shall not be considered an incandescent light source.

262 Appendix 11

(b) All fi xtures used for event lighting shall be fully shielded as de fi ned in Section 5 of this Code, or be designed or provided with sharp cut-off capability, so as to minimize up-light, spill-light, and glare.

(c) All events shall be scheduled so as to complete all activity before or as near to 10:30 p.m. as practical, but under no circumstances shall any illumination of the playing fi eld, court, or track be permitted after 11:00 p.m. except to con-clude a scheduled event that was in progress before 11:00 p.m. and circum-stances prevented concluding before 11:00 p.m.

Exception: (City only.) Any portion of a recreational facility located within 300 ft of a road or street designated as a scenic route shall be lighted using only fi xtures approved for use under this Code for the Area, as de fi ned in Sections 4.4 and 4.5 of this Code, in which said recreational facility is located.

Exception: (County only.) Recreational facilities located along roads and streets designated as scenic routes shall be lighted using only fi xtures approved for the Area in which they are located.

Section 10.2. Outdoor Display Lots. Any light source permitted by this Code may be used for lighting of outdoor display lots such as, but not limited to, automobile sales or rental, recreational vehicle sales, or building material sales, provided all of the following conditions are met:

(a) Lighting for parking lots and other areas surrounding the display lot shall com-ply with this Code for lighting in the speci fi c area as de fi ned in Sections 4.4 and 4.5 of this Code.

(b) All fi xtures used for display lighting shall be fully shielded as de fi ned in Section 5 of this Code, or be designed or provided with sharp cut-off capability, so as to minimize up-light, spill-light, or glare.

(c) Display lot lighting shall be turned off within 30 min after closing of the busi-ness. Under no circumstances shall the full illumination of the lot be permitted after 11:00 p.m. Any lighting used after 11:00 p.m. shall be used as security lighting.

Section 12 Other Exemptions

…Section 12.1. Nonconformance

1. Mercury vapor lamps in use for outdoor lighting on the effective date of the ordinance codi fi ed in this chapter shall not be so used.

2. (City) Bottom-mounted outdoor advertising sign lighting shall not be used. (County) Bottom-mounted outdoor advertising sign lighting shall not be used, except as provided in Section 7.

3. All other outdoor light fi xtures lawfully installed prior to and operable on the effective date of the ordinance codi fi ed in this chapter are exempt from all requirements of this Code except those regulated in Section 7 and in minor

263Appendix 11

Sections 9.3 and 9.4 and in Section 10. There shall be no change in use or lamp type, or any replacement or structural alteration made, without conforming to all applicable requirements of this Code.

…Section 12.2. Fossil Fuel Light. All outdoor light fi xtures producing light directly by the combustion of natural gas or other fossil fuels are exempt from all require-ments of this Code.

…Section 12.3. State and Federal Facilities. Outdoor light fi xtures installed on, and in connection with those facilities and land owned or operated by the federal gov-ernment or the state of Arizona, or any department, division, agency or instrumen-tality thereof, are exempt from all requirements of this Code. Voluntary compliance with the intent of this Code at those facilities is encouraged.

Section 15 Violation

It shall be a civil infraction for any person to violate any of the provisions of this Code. Each and every day during which the violation continues shall constitute a separate offense.

Section 16 Enforcement and Penalty

…Section 16.1. (City only) Pursuant to Section 28–12 of the Tucson Code:

1. When a violation of this Code is determined, the following penalty shall be imposed:

(a) A fi ne of not less than 50 dollars nor more than 1,000 dollars per violation. The imposition of a fi ne under this Code shall not be suspended.

(b) Any other order deemed necessary in the discretion of the hearing of fi cer, including correction or abatement of the violation.

2. Failure of a defendant to comply with any order contained in a judgment under this Code shall result in an additional fi ne of not less than 50 dollars nor more than 1,000 dollars for each day the defendant fails to comply.

Section 16.1. (County only) A violation of this Code is considered a civil infraction. Civil infractions shall be enforced through the hearing of fi cer procedure provided by A.R.S. Section 11–808 and Sections 18.95.030, 18.95.040, and 18.101.60 of this Code (The numbering scheme of the Sections is different in the County Code). A fi ne shall be imposed of not less than 50 dollars nor more than 700 dollars for any individual or 10,000 dollars for any corporation, association, or other legal entity for each offense. The imposition of a fi ne under this Code shall not be suspended.


Ambient light The total light level or effect, or amount of light perceived, in one’s surroundings.

Baf fl e A plate inserted within or just outside a luminaire to shield the light from direct view.

Ballast Electrical devices used in conjunction with a discharge lamp to start and control it.

Candela (cd) or standard candle The SI unit of luminous intensity. CfDS The British Astronomical Association’s Campaign for Dark Skies. See

Appendix A.3 and Bibliography. CFL Compact fl uorescent lamp. CIE The Commission Internationale de l’Eclairage (International Lighting Com-

mission), based in Vienna. See Bibliography. Color rendering/rendition The perceived effect on objects of different colours of

lights of different types. Color temperature This term describes the actual colour of the light source itself,

as opposed to that of the light issuing from it. Column The post upon which a lamp is mounted. Cones See rods and cones . Dark adaptation The transition of visual processes within the eye to darker sur-

roundings. See Rods and cones . Disability glare (veiling luminance) Glare causing reduced visual performance.

See Sect. 1.2. Discomfort glare Glare producing discomfort or annoyance without necessarily

interfering with visual performance. See Sect. 1.2.

Glossary

266 Glossary

FCO This stands for full cut-off, referring to a lamp with a fl at glass panel beneath which, when mounted horizontally, emits no light above the horizontal. See also SCO .

Fluorescent A long-life, relatively cheap whitish light source based on a gas dis-charge process, where electrons pass through a tube and interact with a phosphor coating.

Flux Luminous fl ux is the rate of fl ow of particles of light energy, measured in watts or ergs/s.

Fovea A small central depression in the back of the retina containing cone cells: the area of sharpest vision.

Full cut-off See FCO . IDA The International Dark-Sky Association. See Appendix A.2 and Bibliogra-

phy. IESNA/IES The Illuminating Engineering Society of North America. The USA’s

professional guidance body for lighting engineers. See Bibliography. ILP The Institution of Lighting Professionals. The UK’s professional guidance

body for lighting engineers. See Bibliography. Incandescent Describes a light source based on electricity passing through a thin

fi lament (usually tungsten) which glows brightly. Intrusive light See light trespass KWh Kilowatt-hour: unit of energy equal to the work done by 1,000 W of power

acting for 1 h. LED Light-emitting diode. Light spill The emission of light outside the premises which the lighting is sup-

posed to illuminate. Light trespass (intrusive light) Troublesome light entering areas or premises out-

side the boundary of the premises to be illuminated. UK campaigners against light waste tend not to use the term trespass , which has a speci fi c meaning in law. It is not normally the intention of the owners of intrusive lights to cause a problem. They simply do not realise that they are.

Lumen (lm) The SI unit of luminous fl ux, being the fl ux emitted in a solid angle of 1 steradian by a point source with uniform intensity of 1 candela (q.v.).

Luminaire A word not found in many dictionaries, but widely used in the lighting community to denote the lamp and its surrounding casing and optics.

Lux (lx) The SI unit of illumination, being a luminous fl ux of 1 lumen (q.v.) per square metre. The value for the full Moon is about 0.2–0.3 lux.

Melatonin A hormone (N-acetyl-5-methoxytryptamine) secreted during the hours of darkness by the pineal gland.

Obtrusive light Light emitted where it is not needed, causing nuisance or environ-mental degradation.

Photometry The measurement of the level and distribution of light. Re fl ectance The amount of light re fl ected by a given surface (the ratio of the

re fl ected fl ux to the incident fl ux).

267Glossary

Re fl ectivity The ability of a surface to re fl ect radiation (technically, equal to the re fl ectance of a layer of material suf fi ciently thick for the re fl ectance not to de-pend on the thickness).

Rods and cones Cells in the retina of the eye. Rods are cylindrical cells contain-ing rhodopsin (‘visual purple’), and are sensitive to dim light but not to colour. Cones are conical cells which are sensitive to color and bright light. The process of dark adaptation involves the rods taking over visual duties from the cones. In-terestingly, there are no rods in the centre of the fovea ( q.v. ), which explains the astronomer’s ‘averted vision’ trick (objects appearing more distinct if you look slightly to one side of them).

SCO Semi-cut-off: a lamp type which has a shallow bowl beneath, and emits little or no light skywards.

SON Another name for high-pressure sodium sources (see Sect. 1.3). SOX Another name for low-pressure sodium sources (see Sect. 1.3). Skybeam, sky beam A concentrated beam of light sent into the sky deliberately,

usually for the purposes of advertising (often erroneously called a ‘laser’). Sky glow, skyglow Unwanted light emitted into the night sky from poorly aimed

lamps. Stray light See Light spill . Street furniture All manufactured items commonly seen along roadsides. e.g.

lighting columns, telephone poles. Veiling luminance See Disability glare . Visibility Clarity of vision; how well we see something. The purpose of a good

light should be to increase visibility: to reveal and not conceal. UWLR, ULR, Upward fl ux The abbreviations stand for Upward (Waste) Light

Ratio. All these terms refer to the relative amount of the light emitted above the horizontal.


British Astronomical Association (BAA)/Council for the Protection of Rural England (CPRE) Starry starry night (April 2000, revised 2010)

BAA Campaign for Dark Skies (CfDS) Blinded by the light? A handbook on light pollution (2009) Domestic and commercial security lighting (2009) CfDS Newsletter (twice yearly)

The CfDS Website Has a Light Pollution Reading List www.britastro.org/dark-skies/readlist.htm#tech All BAA/CfDS publications are available from BAA, Burlington House, Piccadilly,

London W1J 0DU, UK. (0)207 734 4145. E-mail: of fi [email protected]

British Standards Institution (BSI) British Standard (BS)5489 (Code of practice for road lighting). Available from the BSI, 389 Chiswick High Rd, London W4 4AL, UK. (0)208 996 9001

Chartered Institution of Building Services Engineers/Institute of Light and Lighting Lighting guides (LG1 Industrial, LG4 Sports, LG6 The Exterior Environment).

Available from CIBSE/ILL, 222 Balham High Rd, London SW12 9BS, UK. (0)208 675 5211

Bibliography

http://www.britastro.org/dark-skies/readlist.htm#tech


270 Bibliography

Commission Internationale de l’Eclairage (CIE) Guidelines for minimizing urban sky glow near astronomical observatories Guide for fl oodlighting Recommendations for the lighting of roads for motor and pedestrian traf fi c Guidelines for minimizing sky glow Guide to the lighting of urban areas. Available from CIE, Central Bureau,

Kegelgasse 27, Vienna, Austria. (001)431 714 3187

Countryside Commission/Department of the Environment (UK) Lighting in the countryside – towards good practice (ISBN 0-11-753391-2).

Available from The Stationery Of fi ce, PO Box 276, London SW8 5DT, UK. (0)207 873 9090

Department of Transport (UK) Road lighting and the environment. Available from DoT Sales Unit, Government

Building, Block 3, Spur 2, Lime Grove, Eastcote HA4 8SE, UK. (0)208 429 5170

International Dark-Sky Association IDA newsletter (quarterly). Available from [email protected]

The IDA website has a great choice of articles, extracts and references www.darksky.org

Illuminating Engineering Society of North America Recommended practice on roadway lighting (IESNA RP-8-00). Available from

IESNA, 120 Wall Street, New York, NY 10005, USA. 212-248-5000. www.iesna.org

Institution of Lighting Professionals (ILP) Guidance notes for the reduction of light pollution Lighting the environment – a guide to good urban lighting Domestic security lighting, friend or foe? Available from the ILP, Lennox House,

9 Lawford Rd, Rugby CV21 2DZ, UK. (0)1788 576492. www.theilp.org

Royal Commission on Environmental Pollution Arti fi cial light in the environment (2009) www.of fi cial-documents.gov.uk/document/

other/…/9780108508547.pdf

Royal Fine Art Commission Lighten our darkness. Available from RFAC, 7 St James’s Square, London SW1Y

4JU, UK. (0)207 839 6537





http://www.theilp.org

http://www.official-documents.gov.uk/document/other/�/9780108508547.pdf

http://www.official-documents.gov.uk/document/other/�/9780108508547.pdf

271Bibliography

Recommended Reading and Websites

Avery D (1999) The proper use of light therapy. Dir Psychiatr 19:379–398 Baddiley Dr CJ (2007) Towards understanding skyglow. Available through CfDS and ILP Bower J (2000) The dark side of light. Audubon Mag 102(2):92–97 Bruce-White C, Shardlow M (2011) Review of the impact of arti fi cial light on invertebrates.

Buglife, Peterborough, www.buglife.org.uk/News/newsarchive/News+Archive+2011/Save+bugs+from+light+pollution

Campaign for Dark Skies (2009) Blinded by the light? A handbook on light pollution. Order via www.britastro.org/dark-skies

Cinzano P, Falchi F, Elvidge D (2001) The fi rst world atlas of arti fi cial night sky brightness. Mon Not R Astron Soc 328(3):689–707

Clark BAJ (2000) Outdoor lighting principles for Australia in the 21st century. www.gsat.edu.au/astrovic

Coren S (1996) Sleep thieves: an eye-opening exploration into the science and mysteries of sleep. Free Press, New York. ISBN 0-684-82304-7, in IDA ( www.darksky.org ) information sheet 108

CPRE (2003) Night blight. www.cpre.org.uk Crow D (1999) The story of light. Light J, Jan–Feb DEFRA (2000) Our countryside: the future – a fair deal for rural England, The UK Stationery

Of fi ce. www.defra.gov.uk/rural/ruralwp/whitepaper/chapter9.htm#9.4.2 Eisenbeis G (2006) Arti fi cial night lighting and insects: attraction of insects to streetlamps in a

rural setting in Germany, chapter 12. In: Rich C, Longcore T (eds) Ecological consequences of arti fi cial night lighting. Island Press, Washington, DC

FLAP: Fatal Light Awareness Program, Toronto. Various publications. www. fl ap.org Haim A, Kloog I, Portnov BA, Rennert HS (2011) Does the modern urbanized sleeping habitat

pose a breast cancer risk? Chronobiol Int 28(1):76–80 Harris J (1993) Lighting the queen’s highway. Light J 58(4):245 Henshaw C (1994) The environmental effects of light pollution. J Br Astron Assoc Lett 104(1):3.

Available in pdf format at http://articles.adsabs.harvard.edu/full/seri/JBAA./0104/0000313.000.html

Henshaw C, Cliff G (2006) Is light pollution killing our birds? Challenge Mag, Summer Huemer P, Kühtreiber H, Tarmann G (2010) Anlockwirkung moderner Leuchtmittel auf nachtak-

tive Insekten. www.hellenot.org Isobe S, Environment Agency of Japan (1998) Guidelines for light pollution: aiming for good

lighting environments Jewkes P (1998) Light pollution: a review of the law. J Plan Environ Law Jewkes P (1998b) Light pollution and the law: what can you do? J Br Astron Assoc

108(5):258–260 Lockley S (2009) Human health implications of light pollution. In: Mizon W (ed) Blinded by the

light? CfDS 2009. British Astronomical Association, London, pp 21–25 Klinkenborg V (2008) Our vanishing night. National Geographic McNally D (ed) (1994) The vanishing universe: adverse environmental impacts on astronomy.

Cambridge University Press, Cambridge. ISBN 0-521-45020-9 Kloog I, Haim A, Stevens RG, Barchana M, Portnov BA (2008) Light at night co-distributes with

incident breast but not lung cancer in the female population of Israel. Chronobiol Int 25(1):65–81

Marchant P (2006) Shining a light on evidence-based policy: street lighting and crime. Crim Just Matter no. 62. The Centre for Criminal Justice Studies, Kings College, London, p 18

Marchant PR (2011) Have new street lighting schemes reduced crime in London? Radic Stat 104:39–48

http://www.buglife.org.uk/News/newsarchive/News+Archive+2011/Save+bugs+from+light+pollution

http://www.buglife.org.uk/News/newsarchive/News+Archive+2011/Save+bugs+from+light+pollution


http://www.gsat.edu.au/astrovic

http://www.gsat.edu.au/astrovic


http://www.cpre.org.uk

http://www.defra.gov.uk/rural/ruralwp/whitepaper/chapter9.htm#9.4.2

http://www.flap.org

http://articles.adsabs.harvard.edu/full/seri/JBAA./0104/0000313.000.html

http://articles.adsabs.harvard.edu/full/seri/JBAA./0104/0000313.000.html

http://www.hellenot.org

272 Bibliography

Mizon B (1998) Heaven’s light. Astron Now. Light pollution Mizar Astronomy/CfDS, 2000 with Baskill D (2010) Stolen stars: a young adult’s guide to light pollution. www.britastro.org/dark-skies

de Molenaar JG et al (2003) Road illumination and nature. IV. Effects of road lights on the spatial behaviour of mammals. Alterra Green World Research, Wageningen

Morgan-Taylor M (1997) And God divided the light from the darkness: has humanity mixed them up again? Environ Law Manage 9(1):32–39

Mostert H (1983) A clear-sky detector using re fl ected arti fi cial light. J Br Astron Assoc 93(5):205–209

Nash D. Filters. www.xmission.com/~dnash Pearce F (1995) Declaring a curfew on aurora metropolis. New Sci 145:44–45 Pollard N (1994) Skyglow-conscious lighting design. Int J Light Res Technol 26(3):151–156 Floodlighting the outdoor environment – a waste of energy? http://www.iaeel.org/iaeel/Archive/

Right_light_proceedings/Proceedings_body/BOK3/200/3099.PDF Purves L (1998) Light pollution. In: Barnett A, Scruton R (eds) Town and country. Cape, London.

ISBN 0-22-405-2500 Ramsey M, Newton R (1991) The in fl uence of street lighting on crime and fear of crime. Home

Of fi ce Crime Prevention Unit (HOCPU) papers 28 and 29. Home Of fi ce, London Ratledge D (ed) (1997) The art and science of CCD Astronomy. Springer, London Rich C, Longcore T (2006) Ecological consequences of arti fi cial night lighting. Island Press,

Washington, DC. ISBN 1-55963-128-7 Sherman L, Gottfredson D, MacKenzie D, Eck J, Reuter P, Bushway S (1997) Preventing crime:

what works, what doesn’t, what’s promising. A report to the United States Congress. Prepared for the National Institute of Justice. Department of Criminology and Criminal Justice, University of Maryland at College Park

Simpson M (1995) Social factors behind the development of outdoor lighting. Light J 60(3):137 Tonkin S (2000) Astro FAQs. Springer, ISBN 1-85233-272-7. Website ( fi lters, etc.). www.astunit.

com Witherington BE (1997) The problem of photopollution for sea turtles and other nocturnal ani-

mals. In: Clemmens JR, Buckholz R (eds) Behavioural approaches to conservation in the wild. Cambridge University Press, Cambridge, pp 303–328

Wright P, Paterson J. Understanding and dealing with obtrusive light – a practical guide to help planners and designers to appreciate and deal with problems of light pollution. www.lcads.com/pollution/ObtrusiveMain.html

A Long List of Articles on Light Pollution Can Be Found on

http://www.weasner.com/etx/lp/index.html

Websites on Light Pollution

calgary.rasc.ca/lp/frame.html www.environmental-protection.org.uk/neighbourhood-nuisance/light-pollution www.globeatnight.org www.jshine.net/astronomy/dark_sky www.lightpollution.it www.lightpollution.org.uk



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http://www.astunit.com



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http://www.jshine.net/astronomy/dark_sky

http://www.lightpollution.it

http://www.lightpollution.org.uk

273Bibliography

www.need-less.org.uk www.njaa.org/light.html www.utahskies.org/light-pollution

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63405-9 Karkoschka E (1999) The observer’s sky atlas. Springer, New York. ISBN 0-387-98606-5 Ridpath I (ed) (1989) Norton’s 2000.0 star atlas and reference handbook. Longman/Wiley, ISBN

0-470-21460-0: USA; 0-582-03163-X: UK Tirion W, Rappaport B, Lovi G (1987) Uranometria 2000.0, 2 vols. Willmann-Bell, Richmond.

ISBN 0-943396-14-X

http://www.need-less.org.uk

http://www.njaa.org/light.html

http://www.utahskies.org/light-pollution


About the Author

Bob Mizon, MBE, FRAS, is a planetarium operator and astronomy lecturer, best known in the scienti fi c and environmental community as the co-coordinator of the British Astronomical Association’s Campaign for Dark Skies, which aims to turn back the tide of light pollution which has seriously affected our view of the stars over the last 60 years.


A a Cap , 155 a Gem , 166 a Lyr , 172 57 Aql , 144 1 Ari , 145 14 Aur , 146–147

B b 918 , 186

C “Cassiopeia” look alike , 149–150 57 Cnc , 150 61 Cyg , 161–162

D 5 and 6 Dra , 164–165

G g And , 139–140 g Vir , 188

H h3945 CMa , 152–153 HU Tau , 182

I IC 4665 , 173 IC 4756 , 180–181 i Boo , 147, 185 i Tri , 184

K k Boo , 147, 185 Kemble’s Cascade , 148

L l Ari , 145 3 and 6 Leo , 169

M M3 , 152 M33 , 108–110, 159, 183 M67 , 150–151 M92 , 167 Mel 111 , 160

N NGC 457 , 155–157 NGC 752 , 140–141, 143 NGC 1582 , 177 NGC 1647 , 181, 182 NGC 1907 , 146

Object Index

278 Object Index

NGC 2419 , 164, 170 NGC 2683 , 171 NGC 2880 , 185 NGC 2903 , 169 NGC 3245 , 170 NGC 3992 , 186–187 NGC 6210 , 167 NGC 6633 , 173–174, 180 NGC 6866 , 163 NGC 6934 , 164 NGC 6939 , 158 NGC 6940 , 188–189 NGC 6946 , 158–159 NGC 7006 , 163–164, 170 NGC 7209 , 167–168 NGC 7296 , 168 NGC 7331 , 5, 175, 176 NGC 7538 , 159

O O S 182 CMi , 154 O S 98 Ori , 175 O S S 254 Cas , 155

P Pairs, Cam-Cas , 149–150 3 Peg , 175 y 1 Psc , 178 p 1 UMi , 187

R R Aql , 144–145 R Ser , 180, 181 RW Cep , 158, 159

S SAO 7611 , 164–165 SAO 50246 , 162–163 13 Sge , 179 15 Sge , 179 S 101 , 160 S 239 , 184

S 297 , 176 S 670 , 181 S 674 , 182 S 680 , 182 S 1149 , 154 S 1374 , 170 S 1639 , 160 S 1795 , 185, 186 S 2391 , 180 S 2398 , 164, 165 S 2813 , 157, 158 S 2816 , 157, 158 S 2819 , 157, 158 S 2838 , 141–142 S 2970 , 142–144 s Ori , 174 s 2 UMa , 184 St 4 , 177

T t 1 Aqr , 142–144 T CrB , 160–161 T Lyr , 172 Tr 1 , 156–157

U 83 Uma , 185–186 U Sge , 178–179

W W CMa , 153 Wristwatch , 148 WZ Cas , 155, 156 WZ Sge , 179

Y Y CVn (La Superba) , 151–152

Z z CrB , 160, 161


A Action, courses of , 127, 213–217, 253 Aerosols , 10, 40 American Medical Association (AMA) ,

80, 82 Andromeda Galaxy , 4, 11, 139–141 Antoniadi scale , 9 Architects , 210–212 Astronomers , 3, 9, 10, 15, 18, 26, 27, 40, 47,

55, 66, 67, 103, 105, 114, 122, 127, 133, 135, 175, 193–196, 198, 199, 203, 209, 212–214, 216, 231, 247–249, 251, 253

Astrophotography , 6 Atmosphere , 8–11, 13–15, 17, 38, 40, 48, 50,

51, 105, 107, 198, 220 Auer von Welsbach, Carl , 35 Aurora , 9, 17, 19, 227, 228 Authorities, local , 59, 67, 69, 72, 89,

193, 199, 206–210, 214, 224, 228, 243, 244, 246

B Bats , 70, 71, 227 Birds , 67, 69, 70, 72–74, 227, 240 Bortle Scale , 107–112 British Astronomical Association (BAA) ,

48, 70, 77, 145, 188, 194, 197, 204, 227, 230, 231, 254, 269, 273

Buildings, fl oodlighting , 74, 113, 194, 209, 210, 212

C Campaign for Dark Skies (CfDS) , 7, 46–49,

53, 61, 62, 67, 74, 99, 119, 127, 193–196, 200, 203–205, 213, 214, 216, 227, 229, 230, 233, 253–255, 257, 269

Campaigning , 127 Cancer, links between lighting and , 79, 82, 83 Carbon dioxide (CO

2 ) , 57–59, 82, 228, 248

CCDs , 127, 128, 131–133, 135 Chemistry, atmospheric , 83 Church fl oodlighting , 209, 210, 212 Clan du Néon , 54, 55 Clean Neighbourhoods and Environment

(CNE) Act , 66, 67, 228, 244 Clear sky detector , 105 Coatham, David , 105 Commission Internationale de l’Eclairage

(CIE) , 196, 224, 258, 269, 274 Contrails , 10–12 Corneille , 30 Cost of wasted light , 53, 54, 57, 59, 205, 214,

240, 253 Crawford, David , 48, 49, 216, 247 Crime , 41, 89–101, 127, 209, 212, 214, 216,

239, 245, 250, 255, 258

D DEFRA , 57, 58 Deneb , 24, 25 Digges, Leonard , 3

Subject Index

280 Subject Index

E Earthshine , 14, 15 Edison, Thomas , 35 Education , 59, 74, 127, 195, 202, 203, 205,

206, 214, 221, 238 Eisenbeis, Gerhard , 67 Electromagnetic spectrum , 13, 14, 251 Elements, stellar origin of , 26 Energy waste , 53–56, 59, 216, 229, 247, 253 Environment, adverse effects on , 62–75 Environmental Health Of fi cers , 97, 228, 254 Eye, human , 3–8, 23, 26, 34

F Fatalities , 78 Filters , 114, 127–131, 135, 183 Fossil fuels , 16, 62, 83, 228, 267 Foster, Russell , 6 Fovea , 6, 270, 271

G Galileo , 12, 14 Gegenschein , 30–31, 108 Glare , 38, 39, 43, 53, 62–65, 77, 81, 89–94,

97–100, 115, 116, 124, 135, 172, 195, 200, 201, 206, 208, 209, 215, 216, 228, 229, 235, 236, 239, 240, 247, 249, 250, 253–255, 259, 260, 266, 269, 271

Globe lights , 117–123, 196 Glow-worms , 70, 71, 227 Good Lighting Award , 62, 74, 194, 197,

204, 207 Great Wall , 50 Greenhouse gases , 62, 203, 235, 246 Guidance notes, ILP , 97, 99, 112, 203, 209,

235–241, 274 Guidelines, governmental , 257–258

H Health, lighting and , 77–84 Herschel, William and Caroline , 118 Highways Agency (HA) , 61, 204, 254 Hipparchus , 26 Home Of fi ce , 92, 96, 97 Hunter, Tim , 48, 49

I IDA advice , 214, 253–255 Illuminating Engineering Society of North

America (IENSA) , 63, 270, 274

Insects , 4, 67, 69, 70, 73, 240 Institution of Lighting Professionals (ILP) , 97,

105, 112, 122, 196–198, 201, 203, 231, 235–241, 254, 257, 270, 274

International Dark-Sky Association (IDA) , 48–50, 54, 83, 96, 115, 122, 127, 194, 196, 203, 213, 214, 216, 224, 225, 238–239, 247–251, 253–255, 257, 259–261, 263, 270, 274

Invertebrates , 68, 69

J Janssen, Zacharias , 3 Jewkes, Penny , 67, 243 Jupiter , 7, 13, 16, 19, 21, 108

K Knowles, Joseph , 112

L Lamps

compact fl uorescent (CFL) , 35, 36, 99, 116, 260, 261, 269

cost of , 112, 116, 240, 251, 257, 261 discharge , 35, 36, 113–116, 228, 269 early , 33–40, 118, 198, 228 fl uorescent , 99, 116, 264 full cut-off (FCO) , 61, 64, 99, 101, 123,

124, 136, 251, 254, 260, 270 LED , 36, 113, 116, 117, 211, 229, 232, 270 mercury , 35, 36, 70, 115, 129, 228, 249,

250, 264, 266 metal halide , 36, 37, 70, 113, 115, 116,

136, 139, 232, 249, 264 optics in , 60, 79, 112, 122, 123, 270 security ( see Security lights) shielding of ,

67, 71, 122–124, 212, 239, 240, 250, 260, 264, 265

sodium , 35–37, 56, 59, 61, 70, 113–115, 123, 129, 229, 232, 249–250, 254, 264, 271

tungsten-halogen , 99, 100, 113, 115, 229 types of , 113–122, 228–230

Legislation , 67, 74, 193, 195, 202, 203, 205, 244, 245

Legislators , 103, 195, 197, 203–206, 214 Lighting

adverse impacts of , 53–75, 103, 241, 254, 257

development of , 69, 208, 228, 236, 238, 243, 257

281Subject Index

rural , 65, 90, 98, 99, 108–109, 116, 130, 199, 200, 208, 209, 211, 213, 227, 240, 257

Light intrusion, trespass , 65–67 Light, re fl ected , 22, 37, 69, 105–107, 115,

119, 123, 228, 255, 270 Light therapy , 80 Lippershey, Hans , 3 Local Plans , 206, 208–210, 214 Lockley, Steven , 7, 79, 80

M M31 , 4, 5, 11, 110, 111 Macfarlane, Robert , 206 Magnitudes , 18, 19, 24, 26, 27, 38, 47, 48,

108–112, 140, 144, 147, 151, 153–158, 160, 162, 165, 166, 168–171, 173, 174, 176, 177, 183, 185–187, 189, 199

Manufacturers , 92, 97, 99, 103, 122–124, 196–203, 247, 249, 251, 257, 258

Mars , 18, 19, 21 McManus, Francis , 67 Measurement , 103–107, 156, 243, 258, 270 Media , 194, 213, 229 Melanopsin , 7 Melatonin , 8, 79, 270 Mercury , 18, 20 Milky Way , 4, 5, 11, 14, 16, 24, 27, 29, 38, 42,

108–111, 137, 153, 159, 164, 167, 175, 178–180, 214, 227, 245, 247

Missions, space , 12 Mohar, Andrej , 53 Moon , 3, 4, 14, 22, 23, 26, 27,

35, 71, 74, 112, 128, 135, 173, 179, 180, 270

Moonlight , 14, 22–23, 183, 186, 211 Morgan-Taylor, Martin , 49, 57, 93, 245 Mostert, H.E. , 105 Murdoch, William , 35 Myths, lighting , 227, 247–251

N Nash, David , 130, 131 National Institute of Justice , 93 Novae , 27, 28, 160, 161, 179, 188

O Olbers’ Paradox , 15 Organisation, anti-light-pollution , 91, 202

P Plans, local , 206, 208–210, 214 Pole Star , 24, 25, 199 Provencio, Ignacio , 7 Proxima Centauri , 24 Ptolemy , 26, 27 Purves, Libby , 42, 43

Q Quality of life, effect on , 77–84, 206, 221,

251, 254

R Reserves, dark-sky , 105, 203 Retailers , 96, 97, 201, 202, 212, 257, 258 Retina , 6, 23, 270, 271 Rhodopsin , 6, 23, 271 Rhythms, circadian , 6–8, 69, 72, 79, 80 Rods and cones , 6, 269, 271

S Saturn , 7, 19, 215 Scagell, Robin , 70 Science and Technology Select Committee ,

97, 193, 205 Security lights , 43, 62, 72, 78, 80, 92–95, 97,

99, 197, 201, 209, 212, 215, 216, 245, 250–251, 255

Seeing , 9, 91, 110, 143, 146, 147, 151, 154–158, 162, 163, 165–169, 171, 173, 174, 176, 177, 183, 185–187, 189, 206, 229, 232, 239

Sensor , 38, 97–100, 201, 238, 239, 241, 250, 260

Shielding , 9, 66, 67, 71, 97, 118, 122–124, 136, 212, 239, 240, 250, 260, 264, 265

Simpson, Michael , 198, 199 Skyglow , 40–48, 53, 62, 97, 103, 105, 111,

113, 115, 119, 124, 129, 135, 187, 194, 199–201, 209, 216, 221, 227–229, 235, 241, 248, 249, 253, 271, 274

Skyglow, measuring , 103–107 Sky quality meter (SQM) , 103, 104 SQM See Sky quality meter (SQM) Starlight , 15, 24–30, 50, 71, 129, 219–224 StarLight Conference , 50, 219–224 Starry starry night, 227–230, 254, 273 Stearn, C.H. , 35 Sullivan, Woody , 47

282 Subject Index

Sun , 3, 4, 9, 11, 15–18, 24, 26, 30, 31, 40, 63, 105, 128, 151, 162, 167, 179, 186, 187

Sunlight , 11, 14, 16–22, 29, 30, 81, 83 Supernovae , 26, 27, 129, 159, 188 Survey, CfDS , 46, 47, 74 Swan, Joseph , 35, 36

T Tonkin, Stephen , 131 Topham, Frederick , 35 Tucson , 115, 193, 206, 263–267 Turtles , 71, 72 Tycho , 27

V Venus , 13, 18, 20, 108

W Water, in atmosphere , 10 Watling Street , 24 Webster, Tom , 49, 231 Wildlife, effects on , 53, 67–75, 221, 240 Wimborne , 95

Z Zodiacal light , 29–30, 108–110, 228

Light Pollution: Responses and Remedies

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