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Transcript of 2015 Astronomical Calendar
AntaresAntares
HadarHadar
DenebDeneb
MimosaMimosa
AcruxAcrux
SpicaSpica
AltairAltair
FomalhautFomalhaut
VegaVega
AchernarAchernar
ArcturusArcturus
RigilkentRigilkent
SunSun
CanopusCanopus
SiriusSirius
ProcyonProcyon
RegulusRegulus
CapellaCapella
PolluxPollux
AdharaAdhara
AldebaranAldebaran
CastorCastor
RigelRigel
BetelgeuseBetelgeuse
Astronomical Calendar 2015Astronomical Calendar 2015
DenebStellated stars
COVER PICTURE: Stellated Stars. Before we discovered thatstars are huge globes of hot matter, we saw them aspoints of light with spiky rays sticking out. All stars exceptthe Sun are so far away that they would appear as pointsonly, with essentially no radius, but the optics of the eye—and of cameras—spreads the light of the brighter pointsand adds these shimmering spikes. That is why stars areconventionally drawn as little shapes with radiating spikes.And that is why geometric shapes with triangles stickingout of them are called stellated, “starred.” And if the sym-bol is merely made of radiating lines instead of triangles, itis an asterisk, “little star.”
(Merriam-Webster’s website, after briefly defining stel-lated, adds: “This word doesn’t usually appear in our freedictionary, but the definition from our premium UnabridgedDictionary is offered here on a limited basis. To access thecomplete Unabridged Dictionary, with an additional300,000 words, start a free trial . . .” “What,” commentsLarry Bohlayer, who told me about this, “they will takeaway our word? May we no longer use it once the freetrial period is over?” Well, we will use it.)
Here is a row of polygons (many-sided two-dimension-al figures—Greek polys, “much” or “many,” and gônia,“corner” or “angle”):
They are the triangle, quadrangle, pentagon, hexagon,heptagon, octagon (first two names Latin-derived, the oth-ers Greek). Actually these are just the special cases ofthem that have equal sides and angles, the first two beingthe equilateral triangle and the square. And here they arestellated:
The stellations, if that is what they are called—the tri-angles added to each face—can have any height, or theycould even cut inward; I’ve just chosen a radius from thecenter to the tips that is twice that of the radius to the cen-tral polygons’ corners.
You can see what happens if, instead, this distance ischosen carefully so that the stellation’s sides are in linewith the inner polygon’s sides. (This is impossible with,
only, the triangle and square—the lines would run to infin-ity,) The stellated hexagon (“Star of David”) could bedrawn as two triangles superimposed. The stellated pen-tagon (pentagram, a symbol of life, reminiscent of ahuman being, with head and four limbs), and the 7- and 8-pointed shapes, could be drawn continuously with strokesthat cross over each other in running to non-adjacent tips.
Polygons tend to become heavy with symbolism. I’venoticed that some police badges are, for some reason, anonagon (9-pointed, should be enneagon) with not-quite-continuous short stellations.
And then, polyhedrons, or, if you prefer, polyhedra.They are many-faced three-dimensional figures. Whenthe Greeks came to talk about geometrical solids, the termthey chose for what we call a “face” was hedra, “seat.” (In
2 INTRODUCTION
WHERE?
HIGHLIGHTS OF THE YEAR?
TIME ZONES
BLOCK CALENDAR
4 ALL-YEAR CHART
ALL-SKY CHART
CONTENTS
6 JANUARY
8 FEBRUARY
10 MARCH
12 APRIL
14 MAY
16 JUNE
18 JULY
20 AUGUST
22 SEPTEMBER
24 OCTOBER
26 NOVEMBER
28 DECEMBER
30 SCENES
32 SUN, EARTH, AND SEASONS
34 COVER PICTURE, CONTINUED
35 MOON
37 SPECIAL MOONS
38 YOUNG MOON, OLD MOON
40 MERCURY; VENUS
42 MERCURY AND VENUS HORIZON SCENES
44 MARS
45 OUTER PLANETS
46 JUPITER
48 SATURN
50 URANUS AND NEPTUNE
51 PLUTO
52 ASTEROIDS
54 COMETS
58 OCCULTATIONS
60 METEORS
63 ECLIPSES
68 ZODIAC CHARTS
72 MAGNITUDE GRAPH
ELONGATION GRAPH
73 GLOSSARY
74 RISING AND SETTING
Continued on page 34
Sponsored by
The Department of Physics, Furman University,
Greenville, South Carolina
The Astronomical League9201 Ward Parkway, Suite 100, Kansas City, MO 64114
816-DEEP-SKY www.astroleague.org
Universal Workshopwww.Universa lWorkshop.comRaynham, Mass., and Lyme Regis, England
ASTRONOMICAL CALENDAR
2015
by
Guy Ottewell
2 Astronomical Calendar 2015
Copyright © 2014 by Guy Ottewell. Printed in the United States ofAmerica. All rights reserved. Parts may be reproduced with prior permis-sion and with acknowledgment.
ISBN 978-0-934546-70-6 ISSN 1051-6174
The first small issue of this annual book was for the year 1974.
Some other publications by Guy Ottewell:
The Astronomical CompanionGeneral guide to astronomy (not annual), with many 3-D diagrams
Albedo to ZodiacGlossary of astronomical terms, with pronunciation, origin, meaning
To Know the StarsYoung people’s introduction to astronomy. NEW EDITION 2014
The Thousand-Yard Model, or, The Earth as a PeppercornInstructions for a walk making vivid the scale of the solar system
The Under-Standing of EclipsesThe geometry, history, and beauty of eclipses
Berenice’s HairStory of the stolen tress that became the constellation Coma Berenices.
The Troy Town TaleThe whole legend of Troy, in the form of a novel
Portrait of a MillionPoster conveying the concept of a million, with million-facts
American Indian Map, and Navajo Map
The Arithmetic of VotingLanguage (poems)
Plurry: a musical instrument
The Spiral LibraryStripe Latin: a grammar game
Ten-Minute History of the World; and, Queen Guinevere’s Rules
Think Like a Mother: a photo book of human rights
Turkey, A Very Short History
The Winged Velocipede; or, how to f ly overseas with your bicycle
PrefaceAstronomical Calendar 2015 retains some of the added features of the 2014 issue, while returningto the general layout of previous years. Some readers enjoyed having the material for a monthcollected in one place, others were disconcerted at not finding things where they were accustomedto finding them. Astronomy is multi-dimensional.
I am again heartily grateful to John Goss, now President of the Astronomical League, for proof-reading all parts of the book that I was able to send to him in time. He saved me from many typosand unclarities. And I am grateful to several readers who sent corrections and suggestions.
Alan Hale suggested the comets to be included, and answered my questions about them. The“Meteors” section is founded on the extensive information provided to me by Alastair McBeath.
I’ve been persuaded to start a weblog. I began it with an outburst about the “Multiverse,” andit continues in what may be a wayward manner, with pieces varied rather like the cover-pictureessays of this Astronomical Calendar and not all about astronomy. You might consider visiting it,and if you sign up to it we will stay in touch even if the Astronomical Calendar at last ceases:www.universalworkshop.com/guysblog
Corrigenda to Astronomical Calendar 2014Page 30, section “Earth and Sun in June”: what occurs on June 14 is the earliest sun-
rise, not earliest sunset. This is correct in the “June Events” table on the facing page.72, middle column, paragraph 2: the Earth globes during occultations were oriented,
this time, with celestial north at the top, not ecliptic north.74, column 2, under the heading: delete “The Moon’s varying distance.”85, in the glossary entry for “obliquity”: “98° for Saturn” should be “98° for Uranus.
More information at
www.UniversalWorkshop.com
Earth
Com
et H
alle
y
Oct
May
The path of Halley’s Comet, with sightlinesfrom Earth to Comet during the first four months of 1986
Astronomical Calendar 20145 3
If you are a relative beginner, it may be best to use atfirst only the “Sky Dome” map for the current month(page 6, for instance, if it’s January).
The map is indeed of a dome: it’s center is thezenith (straight overhead), the outer circle is the hori-zon. It’s best as a general rule to have your face (orfeet, if you’re lying on your back or on a long chair) tothe south. This avoids confusion. If at times you wantto face, say, east, rotate the map so that “East” is at thebottom.
If you locate and memorize a few constellationseach month, in a year you’ll know the sky pretty well.
The table on the month’s right-hand page containsbrief entries for many kinds of astronomical events.The times given in parentheses are in Universal Time;TIME ZONES, below, explains how to translate this intoyour clock time.
If the event concerns, say, Jupiter, or a meteor
shower, there will be more information in the JUPITER orMETEORS section later in the book.
Astronomical terms, such as opposition, ecliptic,latitude, retrograde, inferior conjunction, precession,are explained in the GLOSSARY.
Events of the type of “Mars 4.6° N.N.E. of Spica”are conjunctions, or, more exactly, appulses: momentswhen two bodies appear closest to each other from ourviewpoint.
For many events, such as the opposition of a plan-et or the conjunction of two bodies, the exact time maybe when the bodies are below your horizon, but theywill not have moved much a few hours earlier or later.Events most affected by the more exact time and yourposition on Earth are the peaks of meteor showers,and, especially, eclipses and occultations.
The ELONGATION graph, when you get used to it, andeven more richly the ZODIAC CHARTS, allow you to sur-vey the movements of the solar-system bodies in rela-tion to each other throughout the year.
TIME ZONESTimes are mostly given in Universal Time (UT), which is the time at longitude 0°(Greenwich Observatory in England).
To convert UT to the clock time of a time zone, use this map of the zones. For stan-dard time, add the number (if it is negative, subtract it). Then for so-called daylight-saving(summer) time, where used, add 1. If the result is negative, add 24; the date is then in theprevious calendar day. If the result is over 24, subtract 24; the date is in the next day.
For example, UT 0 is these times in America on the previous calendar day:Hawaii 14, Alaska 15, Pacific 16, Mountain 17, Central 18, Eastern 19 Standard TimeHawaii 15, Alaska 16, Pacific 17, Mountain 18, Central 19, Eastern 20 summer Time
Sun Mon Tue Wed Thu Fri Sat2015
Julian Date at1.0 UT of month
12457023.5 2 3
4 5 6 7 8
January9 10
11 12 13 14 15 16 17
18 19 20 21 22 23 2425 26 27 28 29 30 31
12457054.5 2 3 4 5 6 78
February9 10 11 12 13 14
15 16 17 18 19 20 2122 23 24 25 26 27 28
12457082.5 2 3 4 5 6 78
March9 10 11 12 13 14
15 16 17 18 19 20 2122 23 24 25 26 27 28
29 30 31 12457113.5 2 3 45 6 7 8
April9 10 11
12 13 14 15 16 17 1819 20 21 22 23 24 25
26 27 28 29 30 12457143.5 23 4 5 6 7 8
May9
10 11 12 13 14 15 16
17 18 19 20 21 22 2324 25 26 27 28 29 30
31 12457174.5 2 3 4 5 67 8
June9 10 11 12 13
14 15 16 17 18 19 2021 22 23 24 25 26 27
28 29 30 12457204.5 2 3 45 6 7 8
July9 10 11
12 13 14 15 16 17 1819 20 21 22 23 24 25
26 27 28 29 30 31 12457235.5
2 3 4 5 6 7 8
August9 10 11 12 13 14 15
16 17 18 19 20 21 22
23 24 25 26 27 28 2930 31 12457266.5 2 3 4 5
6 7 8
September 9 10 11 1213 14 15 16 17 18 19
20 21 22 23 24 25 2627 28 29 30 12457296.5 2 3
4 5 6 7 8
October 9 1011 12 13 14 15 16 17
18 19 20 21 22 23 2425 26 27 28 29 30 31
12457327.5 2 3 4 5 6 78
November 9 10 11 12 13 14
15 16 17 18 19 20 2122 23 24 25 26 27 28
29 30 12457357.5 2 3 4 56 7 8
December 9 10 11 12
13 14 15 16 17 18 1920 21 22 23 24 25 2627 28 29 30 31 12457388.5
Darker blue means less moonlight in the following night.
WHERE?What parts of the book are true for what parts of theEarth?
When it makes a difference, we refer usually to whatcan be seen from around latitude 40° north (the U.S.A.and Europe). “Around” means that for most purposes afew degrees north or south don’t make much difference.The standard longitude is 0° (Greenwich), but often werefer to what can be seen from eastern North America(around 75° west). All this is “unless otherwise men-tioned.”
Longitude (such as whether you’re in California orEurope) makes no difference to the positions of the starsat, say, 10 PM, very little to the planets; only the rapidlymoving Moon is much affected. It will be about 2° fartheralong its course for each time zone you move westward.
Latitude makes more difference: as you go south,different stars come into view, and for the southern hemi-sphere the sky is considerably different. The large SkyDomes in the monthly pages are for mid-evening at lati-tude 40° north; smaller Domes show the difference at50° north, the equator, and 35° south.
BLOCK CALENDARINTRODUCTION
HIGHLIGHTS OF THE YEAR(See the calendar pages at the dates, and the SECTIONS emphasized.)• Jan: COMET C/2014 Q2 Lovejoy possibly almost at naked-eye brightness.• Feb 8: JUPITER at opposition.• Feb-Mar: clustering of Venus, Mars, Uranus, and the Moon in the evening sky; see SCENES.• Mar 20: total ECLIPSE of the Sun, visible from Faroe, Spitsbergen, and the North Pole!• Apr 4: total ECLIPSE of the Moon, visible from the Pacific region.• May 7: MERCURY highest in evening sky for north-hemisphere observers.• May 23: SATURN at opposition.• May-Jun: VENUS highest in the evening sky.• Jul 6: COMET C/2014 Q1 PanSTARRS at perihelion, possibly at naked-eye brightness.• Jul-Aug: clustering of Venus, Jupiter, Mercury, and Regulus, and the Moon in the evening sky; see SCENES.• Aug: COMET 141P Machholz 2 at perihelion, perhaps magnitude 11.• Sep 13: partial ECLIPSE of the Sun, visible from southern Africa and Antarctica.• Sep 28: total ECLIPSE of the Moon, visible from the Americas, Africa, Europe, much of Asia.• Sep-Oct: clustering of Venus, Mars, Jupiter, Regulus and the Moon in the morning sky; see SCENES.• Oct: COMET 22P Kopff at perihelion, perhaps magnitude 10.• Oct: VENUS highest in the morning sky.• Dec: COMET C/2013 US10 Catalina possibly reaching naked-eye brightness.
4 Astronomical Calendar 2015
13 h 13 h 13 h 13 h
14 h 14 h 14 h 14 h
15 h 15 h 15 h 15 h
16 h 16 h 16 h 16 h 17 h
17 h 17 h 17 h 18 h 18 h 18 h 18 h
19 h 19 h 19 h 19 h 2 0 h 2 0 h 2 0 h 2 0 h 2 1 h 2 1 h 2 1 h 2 1 h 2 2 h 2 2 h 2 2 h 2 2 h 2 3 h 2 3 h 2 3 h 2 3 h
- 10o
- 10o
- 10o
- 10o - 10 o- 10 o- 10 o- 10 o- 10o
- 10o
- 10o
- 10o
- 2 0o
- 2 0o
- 2 0o
- 2 0o - 2 0 o
- 2 0 o- 2 0 o- 2 0 o
- 2 0 o- 2 0 o- 2 0 o- 2 0 o
- 2 0o
- 2 0o
- 2 0o
- 2 0o
- 30o
- 30o
- 3 0o
- 3 0o - 3 0 o
- 30 o- 30 o- 30 o- 30
o
- 30o
- 3 0o
- 3 0o
- 4 0o
- 4 0o
- 40o
- 4 0o - 4 0 o
- 40 o
- 40 o
- 40 o
- 4 0 o- 4 0
o- 4 0
o- 4 0 o
- 4 0o
- 4 0o
- 40o
- 4 0o
-50o
-50o
-50o
- 50o
-50o
-50o
-50o
- 50o
- 5 0 o- 5 0 o- 5 0 o- 5 0 o
-50o
-50o
-50o
- 50o
-6
0o
-6
0o
-6
0o
-6
0o
- 6 0 o- 6 0 o- 6 0 o- 6 0 o
-6
0o
-6
0o
-6
0o
-6
0o
-7
0o
-7
0o
-7
0o
-7
0o
-7
0o
-7
0o
-7
0o
-7
0o
- 7 0 o- 7 0 o- 7 0 o- 7 0 o
-7
0o
-7
0o
-7
0o
-7
0o
-8
0o
-8
0o
-8
0o
-8
0o
-8
-8
-8
-8
- 8 0 o- 8 0 o- 8 0 o- 8 0 o
-8
0o
-8
0o
-8
0o
-8
0o
+ 10 o+ 10 o+ 10 o+ 10 o ++++
+ 10 o+ 10 o+ 10 o+ 10 o
+ 10 o+ 10 o+ 10 o+ 10 o
+ 2 0 o+ 2 0 o+ 2 0 o+ 2 0 o + 2 0
o
+ 2 0o
+ 2 0o
+ 2 0o
+ 2 0 o+ 2 0 o+ 2 0 o+ 2 0 o
+ 2 0 o+ 2 0 o+ 2 0 o+ 2 0 o
+3 0 o+ 30 o+3 0 o+ 30 o +30
o
+30o
+ 30o
+3 0o
+ 3 0 o+ 3 0 o+ 3 0 o+ 3 0 o
+3 0 o+ 30 o+3 0 o+ 30 o
+40 o
+40 o
+40 o
+40 o +4 0o
+ 40o
+4 0o
+4 0o
+ 4 0 o+ 4 0 o+ 4 0 o+ 4 0 o
+40 o
+40 o
+40 o
+40 o
+50o
+50o
+50o
+50o +
50o
+50o
+50o
+ 50o+
50o
+50o
+50o
+50o
+6
0o
+6
0o
+6
0o
+6
0o +
60o
+60o
+60o
+60o
+ 6 0 o+ 6 0 o+ 6 0 o+ 6 0 o
+6
0o
+6
0o
+6
0o
+6
0o
+7
0o
+7
0o
+7
0o
+7
0o
+ 7 0 o+ 7 0 o+ 7 0 o+ 7 0 o
+7
0o
+7
0o
+7
0o
+7
0o
+8
0o
+8
0o
+8
0o
+8
0o +
80
o+
80
o+
80
o+
80
o+8
0o
+8
0o
+8
0o
+8
0o
north
galactic
pole
northecliptic pole
APUS
AQUARIUS
AQUILA
ARA
BOÖTES
CANES
VENATICI
CAPRICORNUS
CENTAURUS
CEPHEUS
CIRCINUS
COMA
BERENICES
CORONA
AUSTRALIS
CORONA
BOREALIS
CORVUS
CRUX
DELPHINUS
DRACO
EQUULEUS
GRUS
HERCULES
HYDRA
INDUS
LACERTA
LIBRA
LUPUS
LYRA
MICROSCOPIUM
MU
SCA
NORMA
OCTANS
OPHIUCHUS
PAVO
PEGASUS
PISCES
PISCIS
AUSTRINUS
SAGITTA
SAGITTARIUS
SCORPIUS
SCUTUM
SERPENS
(CAPUT)
SERPENS(CAUDA)
TELESCOPIUM
TRIANGULUMAUSTRALE
TUCAN
A
URSA
MINOR
VIRGO
VULPECULA
G r e a t S q u a r eo f P e g a s u s
Di
pp
er
L i t t l e D i p p e r
the Teapot
the Teaspoon
the Ci rc let
IGC4603
Bug
St a
r Cl o
ud
s
Veil
North America
Cocoon
Ring
Dumbbell
Saturn Nebula
Helix Nebula
OmegaCentauri
M13
M98
M99
M10
6
M61
M100
M84
M85
M86
M49
M87
M88
M89
NGC4565
M90M58
Sombrero
M59M60
M94
M64
Blackeye
M63
Centaurus A
Whirlpool
M83
Pinwheel
ο
λ
ικ
αγβ
ζ
γαAltair
βδ
εζ
ηθ
λ
ι
µ
ε
β
α
π
η γζζ
θ
ι
λ
τδ
φ
ψ3
ω
ν
ο
σ
α
βγ
δ
εζη
θ
αArcturus
ρ
γβ
µδ
εPulcherrima
ητυπ
ζο
λ
κθ
ξ
σψ
β
α
Cor Caroli
αGiedi
βDabih
ψω
ζε
δ γι θ
ρ
δ
γMuhlifainε
βHadar
αRigilkent
ζ
µν
ι
θMenkent
ηκ
ρ
σ
τξ
φυ1
χ
ψ
αAlderamin
β
γ
ι
ζθη
νε
δ
κ
µ
ξ
π
β
α
βγ
α
β
γ
γαβδ θ
θβαGemma
γδεξ
αε
γGienah
δ η
β
αβ γ
δεθ
ηζ
ι
µ
αDeneb
δ
ζ
λ
ξ
τ
ρ
µ
π
εηζ
αγδ β
κ
αThuban
ιθ
η
ζ
χτε
ρπ
ο ξν
βγEltanin
φδ
µArrakis
σ
αKitalphaβ
δ γ
γλ
δ1
βεζ
αAlnair
ιθ
η
ζε
π
σ
τφ
χ
υ
ρθ
ι
β
αRasalgethi
δ Sarin
γ
ω
λµξο
ν
γπ
α
η
βθ
δε
βα
σ
αZubenelgenubi
βZubeneshamali
γ
ι
ε
υτ
θ
ρα
β
δ
ζ
κ
ε
γη
ιτ
σ
οπλµ
φ1
ω
ψχ
θ
αVega
ζ
βγ
δε
κ
ηθ
γ
αβ
δγ
α
ηγ
δβ
ν
ω
φ
ζ
θ
ξ
ηSabik
υε δ
λ
κ
αRasalhague
βCelbalrai
γ
ν
ψ
ι
σ
µ
ηκδβ
γε
ζ
αPeacock
βScheat
αMarkab
ηπ
ξζ
θ
εEnif
κιλµ
τυ
ψ
βγκλ
ιω
θ
ι
ηλε
αFomalhaut
δ γβ µ
αδ β
γ
µ
λ
δ
εKaus Australis η
γφσNunki
τζ
ξοπρυ
α
β2
ι
θ
ρπ
δ Dschubba
βGraffiasνJabbah
σαAntaresτ
ε
ζηθ
ικ υ
λShaula
ξ
β
γδ
γ
αβ
δ
β
ικ
γ
δλα
ε
µ
νξ
ο
η
θAlya
ζ
εαζ
γε
βδ
αAtria
αγ
ε
δMegrez
ε Alioth
ζMizar
ηAlkaid
Alcor
δ
ε
ζη
γ
βKokab
ηγ
θ
αSpicaλ
κ
ιµ
τ
ζ
δ
εVindemiatrix ο
π
αM
il
ky
W
ay
ec
l i p t i c
c e l e s t i a l e q u a t o r
Coordinates of 2000
-1
0
1
2 3 4 5m
ag
ni
tu
de
s
O
B
A
F
G
K
Msp
ec
tr
al
t
yp
es
open cluster
nebula
planetary nebula
globular cluster
galaxy
CASSIO
PEIA
ANDRO
MED
A
0 h 0 h 0 h 0 h
ψ1ψ2
SCU
LPTOR
δ2
πξλ
CHAMAE-
LEON
υ2
φ2
12 h 12 h 12 h 12 h
B
ig
β1
µ1,2
ω1,2
theKeystone
------------vernnal equinox("First Point of Aries")
CAMELO- PARDALIS
Pipe
Coalsack
+ 5 0 o+ 5 0 o+ 5 0 o+ 5 0 o
- 10 o- 10 o- 10 o- 10 o
- 3 0 o- 3 0 o- 3 0 o- 3 0 o
+ 8 0 o+ 8 0 o+ 8 0 o+ 8 0 o
γSadr
CYGNUSηχ
βAlbireo
κι
θο1ο2
σPelican
ν
NGC6992
υε
Genah
Kuma
TrifidLagoon
Edasich
PHO
ENIX
ALL THE YEAR
ALL THE SKY
AQUARIUS
CAPRICORNUS
LIBRA
PISCES
SAGITTARIUS SCORPIUS
VIRGO
OPHIUCHUS
Altair
FomalhautAntares
Spica
JanVenus
Feb
Nov
Dec
Jan
Mercury
Feb
Mar
Sep
Oct
Nov
Dec
Jan
Mars
Feb
Nov
Dec
Saturn
Neptune
Pluto
-30˚
-20˚
-10˚
0˚
+10˚
24h 23h 22h 21h 20h 19h 18h 17h 16h 15h 14h 13h 12h
+10˚
0˚
-10˚
-20˚
-30˚
e c l i p t i c
Mi
lk
yW
ay
Coordinates of 2000
Venus
Mer
cury
Mars
Astronomical Calendar 2015 5
1 h 1 h 1 h 1 h 2 h
2 h 2 h 2 h 3 h
3 h 3 h 3 h 4 h
4 h 4 h 4 h 5 h
5 h 5 h 5 h 6 h 6 h 6 h 6 h 7 h 7 h 7 h 7 h 8 h 8 h 8 h 8 h 9 h 9 h 9 h 9 h 10 h 10 h 10 h 10 h 1 1 h 1 1 h 1 1 h 1 1 h
- 10 o- 10 o- 10 o- 10 o
- 10o
- 10o
- 10o
- 10o - 10 o- 10 o- 10 o- 10 o
- 2 0 o- 2 0 o- 2 0 o- 2 0 o
- 2 0o
- 2 0o
- 2 0o
- 2 0o - 2 0 o
- 2 0 o- 2 0 o- 2 0 o- 3 0 o- 3 0 o- 3 0 o- 3 0 o
- 30o
- 30o
- 3 0o
- 3 0o - 3 0 o
- 30 o- 30 o- 30 o
- 4 0 o- 4 0 o- 4 0 o- 4 0 o
- 4 0o
- 4 0o
- 40o
- 4 0o - 4 0 o
- 40 o
- 40 o
- 40 o
- 5 0 o- 5 0 o- 5 0 o- 5 0 o
-50o
-50o
-50o
- 50o -
50o
-50o
-50o
- 50o
- 6 0 o- 6 0 o- 6 0 o- 6 0 o
-6
0o
-6
0o
-6
0o
-6
0o -
60
o
-6
0o
-6
0o
-6
0o
-7
0o
-7
0o
-7
0o
-7
0o -
70
o
-7
0o
-7
0o
-7
0o
- 8 0 o- 8 0 o- 8 0 o- 8 0 o
-8
0o
-8
0o
-8
0o
-8
0o -
80
o
-8
0o
-8
0o
-8
0o
+ 10 o+ 10 o+ 10 o+ 10 o
+ 10 o+ 10 o+ 10 o+ 10 o+ 10
o
+ 10o
+ 10o
+ 10o
+ 2 0 o+ 2 0 o+ 2 0 o+ 2 0 o
+ 2 0 o+ 2 0 o+ 2 0 o+ 2 0 o + 2 0
o
+ 2 0o
+ 2 0o
+ 2 0o
+ 3 0 o+ 3 0 o+ 3 0 o+ 3 0 o
+3 0 o+ 30 o+3 0 o+ 30 o +30
o
+30o
+ 30o
+3 0o
+ 4 0 o+ 4 0 o+ 4 0 o+ 4 0 o
+40 o
+40 o
+40 o
+40 o +4 0o
+ 40o
+4 0o
+4 0o
+ 5 0 o+ 5 0 o+ 5 0 o+ 5 0 o
+50o
+50o
+50o
+50o +
50o
+50o
+50o
+ 50o
+ 6 0 o+ 6 0 o+ 6 0 o+ 6 0 o
+6
0o
+6
0o
+6
0o
+6
0o
+ 7 0 o+ 7 0 o+ 7 0 o+ 7 0 o
+7
0o
+7
0o
+7
0o
+7
0o
+7
0o
+7
0o
+7
0o
+7
0o
+ 8 0 o+ 8 0 o+ 8 0 o+ 8 0 o
+8
0o
+8
0o
+8
0o
+8
0o +
80
o+
80
o+
80
o+
80
oANDROMEDA
ANTLIA
ARIES
AURIGA
CAELUM
CAMELOPARDALIS
CANCER
CANISMAJOR
CANISMINOR
CARINA
CASSIO
PEIA
CETUS
CHAM
AELEO
N
COLUMBA
CRATERERIDANUS
FORNAX
GEMINI
HOROLOGIUM
HYDRA
HYDRUS
LEO
LEOMINOR
LEPUS
LYNX
MENSA
MONOCEROS
ORION
PERSEUS
PHOENIX
PICTOR
PISCES
PUPPIS
PYXIS
RETICULUM
SCULPTOR
SEXTANS
TAURUS
TRIANGULUM
URSAMAJOR
VELA
VOLANS
Bi
g
D
ip
pe r
Hyades
Beehive
California
M42
M78
Rosette
Cone
Crab
Owl nebula
Andromeda
G
alaxy
M81
M82
M95M96
M105
M108
M65M66
M109
αδDelta
β
Mirach
γ
Almak
µν
θσ
π
ε
ζη
φ
υ
εα
ι
αHamal β
Sheratan
Mesarthim γεδ
ι
αCapella
βMenkalinan
θ
ζε
ητν
δ
π
κ
α
γ
γ
α
β
βαSirius
π
δWezenσε
Adhara ζFurudωη
ιγ
θ
ν3
τ
αProcyon
βGomeisa
γ
α
Avior
ιScutulum
β
Miap
lacid
us
υθ
ω
χ
βCap
h
α
Shed
ir
γ Tsih
δ
Rukbah
ε
κ
ζ
ο
η
θ
ι
π
ιηθ
ζ
τ
υ βDiphda
οMira
δγ
Kaffaljidhmα
λ µ ξ2
π Cet
α
γ δ
θ
βTarf
δAsellus A
αAcubens
γ Asellus B
ι
βε
αγκ
δ
α
δ
β
γ
θε
ζη
γα
β
λ
χφ
κ
ιθAcamar
υ1
ηAzhaεδ
Ranaπγ
Zaurac
BeidKeid
νµ
ωβλ
νβ
α
εMebsuta
τραCastorσβ
υ
δWasat ζ
Mekbuda
γAlmeisan
ηµTejat
ν
ξ
θ
λ
ι
κ
α
ρη σθ
ι
αAlphard
υ1υ2
µν
ξβ
τ
β
η
α
δε
γ
ν
αRegulus
ηγ Algieba
ζµ
ε λ
κδZosma
θChort
βDenebola
ορχ
φ
σ
ι
υ
βο
εβNihal
γδ
θη ζ
αArneb
µ
ικλ
ν
α
γβ
α
ζ
ε
δ
µλ
δ Mintakaε Alnilamζ Alnitak
β
γBellatrixα
Betelgeuse
κ
ο
φ1λµ
ξ
χ2
ν
ρ
ι τη
ψ
υ
σ
ω
γAlgenib
ρβ
Algol
κ
ι
τη
γ
α
ψδ
νε
ξο
µλ
φ
θ
π
συ
αAnkaaκ
εµ
β
γψ
δ
ζ
η
β
γ
α
δεζµνξα
ο
η
φυ
τ
τ
ν
π
ξρ
ζNaos σ
υ
ο
βα
γ
ζ
βγα
εδ
α
α
ζ
αAldebaran
γ
ε
El Nath
οξ
Pleiades
λ
νµ
δ
κυ
θρ
τι
αMothalla
γ
ββζ
αDubhe
βM
erak
γPhad
ικλµ
νξ
ο
τ
υ
φ
θψ
χ
αPolar
is
δο
γRegor
λ
Alsuhailψ
µ φ κ
ν
β
ζγ
δεβα
e c l i p t i c
c e l e s t i a l e q u a t o r
OCTANS
υ4υ3
τ1τ9 τ6
τ5 τ4 τ3
ο1ο2
ERIDAN
US
φ2
π6 12 h 12 h 12 h 12 h 0 h
0 h 0 h 0 h
TUC
AN
A
CENTAU
RUS
Coordinates of 2000
-1
0
1
2 3 4 5m
ag
ni
tu
de
s
O
B
A
F
G
K
Msp
ec
tr
al
t
yp
es
open cluster
nebula
planetary nebula
globular cluster
galaxy
βM33
Double
Cluster
Sirrah
M74
ξ1
RishaMenkar
M77
southgalacticpole
Achernarα
47 Tucanae
θ
λ
T h r e e L e a p s o f t h e Ga z e l l e
DRACO
Mirfak
ζ
Maaz
βPollux
Propusχ1
π1
π5
π4π3π2
Cursa
RigelSaiph
Mi
lk
y W
ay
ζ δε
λMurzim
ν2ξ2 ξ1ο2 ο1
Aludraλκ
η
Canopus
εFalse
Cross
south eclipticpole
υ2
δDORA
DO
- 7 0 o- 7 0 o- 7 0 o- 7 0 o
Large Magellanic
Cloud
Small
Magellanic
Clo
ud
Muscida
23
CEP
HEU
S
vernnal equinox------------
("First Point of Aries")
Maps of the planets’ movements through-out the year. All the major planets keepto the zodiacal band, not departingmore than 8½° from the ecliptic.Declination (vertical) scale isexaggerated by 1.5.
Maps of the whole celestialsphere. Stars are coloredby spectral type.
Coordinates of 2000
ARIES
CANCER
GEMINI
LEO
PISCES
TAURUS
Procyon
Mira
Castor
Pollux
Regulus
Rigel
Betelgeuse
Aldebaran
Mar
Venus
AprMay
Jun
Jul
Aug
Sep
Oct
AprM
ercury
May
Jun
Jul
Aug
Mar
Mars
Apr
May
JunJul
Aug
Sep
Oct
Jupiter
-10˚
0˚
+10˚
+20˚
+30˚
12h 11h 10h 9h 8h 7h 6h 5h 4h 3h 2h 1h 0h
+30˚
+20˚
+10˚
0˚
-10˚
e c l i p t i c
Mi
lk
yW
ay
Uranus
Pleiades
HELIOCENTRIC VIEW of the orbit of Mars. The view is as in theMercury-Venus picture, but with the constellations omitted from the
front side of the sphere for clarity. A circle on the ecliptic plane showsthe mean distance of Mars from the Sun (1.5237 a.u.). The planets are
exaggerated 700 times in size. Dashed lines (each dash or gap 0.05 a.u.long) connect the positions of Earth and Mars at the dates of several suc-
cessive oppositions, showing how the cycle of oppositions is spaced aroundthe orbit. Before Sun-conjunction Mars is in the evening sky, and after it in the
morning sky, as shown by the respectively black and gray curves. Mars’s summersolstice is (as for the Earth) when its north rotational pole is tilted most toward the Sun,
and autumn equinox is when the pole is tilted most backward. The equatorial plane ofMars makes a circle around the sky perpendicular to this pole, cutting its orbital plane in the
directions of Mars’s equinoxes, which happen to be roughly 90° from those of the Earth.
E CL I P T I CP L ANE
v e r n a l e q u i n ox
d i r e c t i one c l i p t i c
ecliptic
e qu a t o r
equator
AQUAR I US
AR I E S
CANCE R
CAP R I CORNUS
GE M I N I
EO
P I S CE S
T AURUS
E a r t h
M a r s
Sun
m e a n d i s t a n c e
Mar
JanSep
Aug
Jul
Jun
MayApr
OctNov
Dec
Feb
eclip
ticno
rth p
ole
Earth
rota
tional
north
pole
Mar
s ro
tational
north p
ole
2007Dec 24
2005Nov 7
2012 Mar 3
2010 Jan 29
2014
Apr
8
2016
May 2
2
oppositio
n
2018 Jul 27
2003Aug
28
Mar
Jan
Sep
Aug
Jul
May Apr
Oct
Nov
Dec
Feb
northern
winter
solstice
northernmostlatitude
aphelion
spring equinox
Sun-conjunction
44 Astronomical Calendar 2015
ARIESCANCER
GEMINI
LEO
TAURUS
VIRGO
M35Beehive
Procyon Mira
Castor
Pollux
Regulus
Betelgeuse
A
AldebaranSpica
AprMayJunJulAugSepOctNovDec Apr 22
Mercury
May 27
Mercury
Jul 16Mercury
Sep 2
Venus
Nov 3Venus
Oct 17Jupiter
ecliptic longitude
eclip
tic la
titude
-15˚
-10˚
-5˚
0˚
+ 5˚
+10˚
+15˚215˚ 210˚ 195˚ 180˚ 165˚ 150˚ 135˚ 120˚ 105˚ 90˚ 75˚ 60˚ 45˚ 30˚
2 3h
4 h
5 h 6 h 7 h 8 h 9 h 1 0 h
1 1 h 1 2 h
1 3 h
1 4 h
+ 3 0 o+ 2 0 o+ 1 0 o
0 o
- 1 0 oe q u a t o r
e c l i p t i c
Mi
lk
yW
ay
Coordinates of 2015
MarsPleiades
Hyades
Sun-conjunctionJun 14
MARSA non-opposition year, in which Mars is distant and small. It starts low in the sun-set sky, disappears beyond the Sun from about April till August, climbs to quitehigh in the morning sky by December.
Mars alternates between “good” years (when it comes to opposition) and bad ones—approximately.
This fourth planet lies 1½ times farther out from the Sun than Earth, taking 1.88 of ouryears to complete an orbit. On our faster inside track, we take 2.13 years to catch up withMars and pass it at the next opposition. The result of this is that the oppositions arespaced around the sky, slightly less than 1/7 of the circle apart, in a slightly-more-than-15-year cycle.
In an opposition year, Mars makes an apparent retrograde loop as we overtake it; lastyear it did so in Virgo. In a non-opposition year like the present, it travels a semicircle thatkeeps it roughly on the other side of the Sun from us. Thus it appears to move almost incompany with the Sun, only slowly overtaken by it, so on the map of the sky it traces along straight inconspicuous track through eight of the twelve zodiacal constellations.
This semicircle is approximately the northern half of its orbit (it is in the northern celes-tial hemisphere from Feb. 21 till Nov. 18—and is slightly further north still because abovethe ecliptic from April 12 onward). But this northerliness is wasted, since Mars is behindthe Sun almost exactly at the middle of the arching path (Sun-conjunction June 14, north-ernmost declination June 26). Even in years when oppositions fall in the northerly part ofthe orbit they are not the best, since it is also very roughly the outer part of the orbit (aphe-lion Nov. 20).
Earth and Mars are curiously similar in rotation: they spin in 24 and 24½ hours,respectively, around polar axes that are tilted 23.44° and 25° to the planes in which theytravel. Moreover the four cardinal points caused by the tilting, which we call the equinox-es and solstices, are distributed in almost the same four directions around the orbits—but with a right-angle difference: the winter solstice of Mars is in the same direction fromthe Sun as the spring equinox of Earth. The two planets are like a man leaning north anda man leaning east as they walk around in circles (try it but don’t lose your balance!).
If in the low western sky of the early months you manage to get dwindling Mars in your
telescope, you’ll see more of its southern hemisphere, its equator being lifted northward.By contrast, if toward the year’s end you study Mars climbing and modestly swelling in thepre-dawn sky, you’ll glimpse its northern polar icecap.
But the icecaps do not mirror each other. Earth’s perihelion and aphelion eachJanuary and July have almost negligible climatic effect, but Mars’s much more widelyvarying distance from the Sun strongly affects its seasons—it receives 45% more solarenergy when nearest than when farthest. Martian winter solstice (Jan. 11) is only a monthafter its perihelion (2014 Dec. 12). The south hemisphere, bulging toward the relativelynear Sun, has, for Mars, a hot summer; the southern icecap may disappear altogether.The north hemisphere, tipped away, has a relatively mild winter. In contrasting years ofsouthern winter and northern summer, the southern icecap may become larger than thenorthern ever does. Thus the result of the asymmetric orbit is moderate seasons for thenorth hemisphere and extreme ones for the south.
--3--2--1012345
m a g n i t u d e s
mean dist. from sun 1.52 a.u.sidereal period 1.88 years = 687 dayssynodic period 2.13 years = 780 dayseccentricity .093inclination 1.9°diameter 6,790 kmsatellites 2
MAP of Mars’s geocentric track against the starry background, ecliptic-based like the Mercury and Venus maps. The scale for thisyear is 11¤3 mm to 1°. The track is drawn in gray when Mars is in the morning sky (after conjunction with the Sun). Parts of thetracks for the neighboring years are included (in blue). Short blue lines connect Mars to other planets when they appear closest.
TABLE OF PHENOMENA. For explanation see the MERCURY and VENUS section.Mars r.a.(2000)dec. hedis gedis elo mag dia”Jan 1 0 21 34 28 -15 36 1.384 1.970 41 1.1 4.8Jan 10 23 winter solstice 22 4 39 -12 54 1.388 2.015 38 1.1 4.6Jan 19 21 .2ºS of Neptune 22 31 9 -10 18 1.392 2.056 36 1.2 4.6Feb 21 17 on equat.,to nor. 0 5 0 0 -4 1.416 2.203 29 1.3 4.2Feb 21 20 .5ºN of Venus 0 5 17 0 -2 1.416 2.204 29 1.3 4.2Mar 11 20 .3ºN of Uranus 0 55 31 5 33 1.434 2.281 24 1.3 4.1Apr 12 6 ascending node 2 23 44 14 16 1.471 2.404 17 1.4 3.9Apr 23 7 1.4ºS of Mercury 2 55 24 16 50 1.485 2.442 14 1.4 3.8May 27 15 1.7ºN of Mercury 4 36 4 22 30 1.530 2.537 5 1.5 3.7Jun 14 16 conjunc.with sun 5 29 47 23 53 1.553 2.568 -1 1.5 3.6Jun 18 1 spring equinox 5 39 47 24 0 1.557 2.573 -1 1.5 3.6Jun 26 19 max.declin.north 6 5 44 24 9 1.568 2.581 -3 1.6 3.6Jul 16 4 .1ºN of Mercury 7 2 12 23 32 1.590 2.586 -9 1.6 3.6Oct 13 21 max.lat.north 10 53 42 8 29 1.659 2.318 -39 1.8 4.0Oct 17 14 .4ºN of Jupiter 11 2 13 7 37 1.660 2.296 -40 1.7 4.1Nov 3 16 .7ºN of Venus 11 40 60 3 34 1.665 2.184 -47 1.7 4.3Nov 18 10 on equat.,to sou. 12 13 38 0 5 1.666 2.073 -52 1.6 4.5Nov 20 23 aphelion 12 19 14 0-30 1.666 2.053 -53 1.6 4.6Jan 1 0 13 47 28 -9 28 1.658 1.684 -71 1.3 5.6
Sep 12016 Mar 1
2003 Aug 28perihelic opposition
2005 Nov 7opposition
2007 Dec 34opposition
2010 Jan 29opposition
2012 Mar 3opposition
2014 Apr 8opposition2016 May 12
opposition2018 Jul 27opposition
Jan 1Mar 1
2015 Jun 14Sun-conjunction
Sep 1Dec 31
2015
eclip
ticno
rth
equa
toria
lno
rth
north polar cap-----
Ma r s1 P H a l l e y
1982
1 P H a l l e y1987
Ne
pt
un
e
E CL I P T I C P L ANE
--
10
AU--
e q u a t o r
equator
e
ec
li
pt
ic
ecliptic
Ju
pi
te
r
S a t u r n
U r a n u s
P l u t o
opp
osition
Oct
12
opposition Sep 1
opposition Jul 6
opposition May 23
Feb 6
opposition
1 C e r e s
v e r n a le q u i n o x
d i r e c t i on
Astronomical Calendar 2015 45
HELIOCENTRIC VIEW of all the planets from Earth(smallest ellipse) outward. The whole orbits areshown in blue (with stalks to the ecliptic plane atyearly intervals); paths for this year in black (stalksmonthly). Besides the major planets, we show afew minor bodies (of which there could be thou-sands in the picture): dwarf planet Pluto; asteroid1 Ceres (as an example of the Main Belt of aster-oids between Mars and Jupiter); and Comet 1PHalley, which at its last visit was first observed in1982, and now, on the scale of the picture, is 16 cm(6.3 inches) from the Sun, approaching its 2023aphelion. The viewpoint has receded to a distanceof 100 astronomical units. The equatorial andecliptic planes are represented by circles aroundthe sky at a distance from the Sun of 35 a.u. Eachdash or gap in the opposition lines is 0.5 a.u. long.
AQUARIUS
CETUS
PISCES
Mira
JanFebMar Feb 22Venus
Mar 1
1U
ranus
Jan 2
0N
eptu
ne
30˚ 15˚ 0˚ 345˚ 330˚ 315˚+15˚
+10˚
+ 5˚
0˚
-5˚
-10˚
-15˚ 0h
1h
2h
2 2h
2 3h
- 2 0o
e q u a t o r
CAPRI-
CORNUS
2015 Dec 31
Phobos
Deimos
2015 Jan 10-6h UT
OUTER PLANETS
THE DISK OF MARS at some dates in this year, alsoat oppositions from the record-breaking near oneof 2003 through the distant one of 2012 to the nextnear one in 2018. The scale is 1 millimeter to 1 sec-ond of arc. The ecliptic plane (almost the same asthe planet’s orbital plane) is horizontal. Short linespoint to the north and south ecliptic poles; longerlines to the celestial poles. Direction to the Sun isshown by an imaginary stick, starting at the centerof the planet (under the dot) and projecting oneplanet-radius beyond the surface. An arrow alongMars’s equator represents its rotation in 2 hours.
MARS AND SATELLITES at the beginning and end of this year. Equatorial north is at top, tosuit observation in telescopes; lines point from the planet to equatorial north and south,shorter lines to ecliptic north and south. Scale is 1 mm to 1 second. The satellites go aroundMars in almost circular orbits and in planes slightly varying from its equator. Their tracksare shown (in white) for 6 hours, starting at 0h UT, which is 7 p.m. Eastern Standard Timeor 4 p.m. Pacific Standard Time ON THE PREVIOUS CALENDAR DATE. The rest of the orbit is inblue, with ticks at 1-day intervals. The orbits are drawn thicker where the satellites are near-er to us than the center of the planet. Phobos goes around in only 7.65 hours, Deimos in30.3 hours. Since Mars rotates in 24½ hours, Phobos travels more than three times fasterthan the planet’s surface: seen by a Martian, Deimos goes over slowly from east to west(more than 2 days from rising to setting), but Phobos goes in the opposite direction, risingin the west and setting in the east, twice a day! (Compare the arrow on Mars’s equator, rep-resenting rotation in 2 hours, with Phobos’s larger movement in half that time.) The satel-lites are exaggerated 30 times in size. Both are elongated: dimensions of Phobos are27x22x19 kilometers, and Deimos 15x12x11 (as against the 6800 km diameter of Mars).Look closely and you will see that they are shown as ellipses. They rotate synchronously:that is, keep the same face to Mars. They are very faint: the magnitude of Mars is 1.1 onJan, 1, 1.3 on Dec. 31, whereas Phobos and Deimos are about 13 and 14 magnitudes fainter.
60 Astronomical Calendar 2015
Meteoroids are bits of solid matter out in space.Encountering Earth’s atmosphere, and still moving atEarth-relative speeds from about 70 to 10 kilometers persecond, they vaporize from friction, giving off light that isseen as meteors or “shooting stars”; sometimes leavingluminous trains for some minutes, or flaring bright enoughto be called fireballs , or causing sounds. Remnants largeenough to reach the ground are meteorites . Most mete-oroids are small—pebbles or dust—and have separatedfrom comets, typically centuries ago. Those that have notdiffused too far apart orbit around the Sun as streams ,appearing as showers when Earth passes through themat about the same dates each year.
Meteors of a shower can appear anywhere in the sky,but, because they are approaching almost in parallel, theirpaths if traced back appear to come from a radiant pointor, rather, small area. From day to day, radiants moveeast because the direction from which the meteors appearto come changes as Earth proceeds around its orbit.
Because streams are vastly wider than the Earth, ashower may be active over days or weeks, though for partof this time shower meteors may have been detected onlyby means of camera or radar. A shower’s peak may bebroad and indefinite or as sharp as hours or minutes.There may be several peaks, implying sub-streams, per-haps of differently sized particles. The times we give arepredictions by experts and may be best guesses. The cal-endar dates may vary by a day because of leap days(which is why scientists prefer to express them by longi-tudes of the Sun); and over centuries they drift later frommonth to month because of the precession of Earth’s axis.
Counts of meteors per hour are the raw data. Azenithal hourly rate (ZHR) is the average number thatwould be seen at the time if the radiant were at the zenithand conditions perfect. Observations help to define astream’s radiant, peak, composition, and origin.
Meteors hitting Earth’s front—because they are trav-eling in retrograde orbits—are seen after midnight andenter the atmosphere at higher speeds. Meteor observingtends to be best before morning twilight!
Sporadic meteors are those untraceable to streams.But also through most of the year (except when maskedby other showers from near the ecliptic in October andNovember) there are meteors coming at low rates from alarge area roughly opposite to the Sun (culminating about1 AM local time). Formerly there were efforts to distin-guish these into many minor showers, but since 2006 theyhave been treated as a general Antihelion Source .
A radiant at or even below the horizon can produce longbright trails across the upper atmosphere. However, thelower the radiant, the fewer meteors from it you will see,so the more favorable observations are made when theradiant is at least 25° to 30° above the horizon.
The other factors are atmospheric conditions and theMoon : if it is in the sky and bright, its light hides all but thebrightest meteors. A First Quarter Moon sets around mid-night, so does not hinder morning observation; LastQuarter rises around midnight. For the more prominentshowers we mention this year’s Moon phase at the end ofthe entry in bold type, or in bold italic if it is markedlyunfavorable.
Make yourself warmly wrapped and comfortable, as ona reclining chair; perhaps face east and gaze up at about45° (easier than overhead, and you notice meteors any-where between horizon and zenith). If the Moon is up,face away from it. Count the shower members you see inan hour. Don’t include those seen by anyone else.Record sporadics separately.
Jan. 4: Quadrantids (peak 2h Universal Time; active Dec.28–Jan. 12, mostly Jan. 1-5). Spoiled this year by FullMoon on Jan. 5. But this shower is worth describing asan introduction to the others. Its radiant is at right ascen-sion 15h20m, declination +49°, about 15° east of Alkaid (hUrsae Majoris at the end of the Big Dipper’s handle). Theradiant’s name is from a defunct constellation. Jérome de
Lalande, in his 1795 edition of Fortin’s celestial atlas, useda dozen faint stars just south of q and i Draconis to formQuadrans Muralis, the “wall quadrant”: a scale of degreesmarked on a wall, for measuring the altitude of a staraligned with a telescope. A constellation isn’t needed inthis star-poor area, and it dropped out of use—except inthe name of these meteors.
They come to us from slightly behind of north (inclina-tion 72° to the ecliptic), so their speed in the atmosphereis medium, about 41 km/s. The radiant is, for people north
of 41° latitude, in the sky all the time. It is down by thenorthern horizon at the beginning of the night; swingsslowly up in the northeast; is 45° high around 3 AM andnearly overhead toward dawn.
Quadrantids may be noticed visually over about 5days. At the peak, rates may be from 60 to 200 per hour.The ZHR is estimated at 120. Faint Quadrantids causedby small particles may peak half a day earlier, and theremay sometimes be a second peak some hours later,detected partly by radio observations. The peak is fairlysharp. At its predicted time this year, the radiant is over-head in Asia. Watch the Quadrantids on the nights beforeand after peak.
Feb. 8: Alpha Cent aurids (12h). The radiant, near aCentauri (Rigilkent, 3rd brightest star), is far south (decli-nation —60°), so most of the meteors are below the hori-zon for northerners. Alastair McBeath notes that, if thisstream is of long orbital period, “there could be a fresh out-burst from it in 2015.” Moon between Full and LastQuarter.
On Feb. 1 and 13 our calendar page lists two show -ers , coming from the directions of Capricornus andSagittarius. These constellations are where the Sun is inFebruary; in other words, the meteors come at us in thedaytime, cannot be observed visually, and have beendetected by researchers using radio waves bounced offthe meteoric particles. Other such ghostly showers areknown in April, May, June, August, and September.
Mar. 25: Gamma Normids , earlier thought to peak aroundMar. 15. A minor and scarcely-observed shower, whoseradiant is around 16h —50° in the deep-southern MilkyWay and so does not rise for those north of Florida. Onlya brief low peak (ZHR 6) that seems to shift betweenMarch 8 and 18. Moon near First Quarter .
Apr . 23: Lyrids (0h; Apr. 16-25). Derived from CometC/1861 G1 Thatcher, which was seen only in 1861, havinga period of 415 years. Coming down at about 80° intoEarth’s orbit, they are medium-swift (49 km/sec throughthe atmosphere); some are spectacularly bright; 20-25%leave persistent trains. The radiant, on the Lyra-Herculesborder not far from Vega, is above the northeast horizon
by 10 PM and overhead by 4 AM. The ZHR isusually around 15-20, but there were outbursts in
1803, 1922 (96/hour), 1982 (250/hour for a few min-utes). The shower has the longest history, beginning with
a Chinese chronicle of 687 BC (when the peak was onMarch 25) and summarized in Gary Kronk’s invaluablebook Meteor Showers. The shower has a narrow peak.Rates may be enhanced in 2015, even more so in 2016and 2017. Moon just before First Quarter .
Apr . 24: Pi Puppids (5h; Apr. 15-28). By contrast withthe Lyrids, they have a southerly radiant, at 7h20m —45°(now 8° farther south than the star p Puppis). They derivefrom Comet 26P Grigg-Skjellerup, which in its 5-year orbit(one of the shortest) has been seen many times since itsdiscovery (by Pons) in 1808. Up to 38 meteors per hourhave been seen from southern countries but only in yearsof the comet’s perihelion, and the comet’s orbit has nowbeen deflected to outside the Earth’s by Jupiter.
May 6: Eta Aquarids (Apr. 19-May 28) are dust from themost famous comet, 1P Halley, which last came by in1986 and will return in 2061. Its retrograde orbit crossesover the October part of Earth’s orbit and back out justunder the May part; so we see sister showers, theOrionids of October (inward) and the Eta Aquarids (out-ward). In both, the meteors are very swift (head-on toEarth), often leaving trains; and there seem to be sub-streams spread over several days, with different averagesizes of particles. The main radiant, near the Urn orWater-Jar or Y of Aquarius, is just below the celestialequator; for latitude 40° north it rises about 2 AM and ishighest toward 8 AM. For the southern hemisphere, nowin autumn, there are more hours of viewing before dawntwilight, and Australians have said this is the best showerof their year. Hourly rates can be as low as 10 for north-erners, as high as 85 for southerners. There may be a 12-year periodicity caused by Jupiter, with one of the low-ratetimes in 2014-2016. Yet the 2013 May 6 Eta Aquaridswere exceptionally strong, up to 140 an hour; meteor sci-entists think this extra dust separated from the cometthree or four thousand years ago. The enhancement isunlikely to continue this year. Moon 2 days past Full.
May 9: Eta Lyrids (May 3-27), from a radiant in Lyrathat is (for the north hemisphere) high in the sky all night,may derive from Comet C/1983 H1 IRAS-Araki-Alcock of1983. Only about 3 per hour, and the “peak” could be 2days later.
June 16: June L yrids (June 11-21). May or may not stillexist. Discovered in 1966, confirmed in 1968 and espe-cially 1969, later dwindled to nothing except for a possibleshowing in 1996. The radiant, 4° south of Vega, is up allnight (for northern observers).
June 24: June Boötids (June 22–July 2), sometimes
AQUARIUS
CAPRICORNUS
LIBRA
OPHIUCHUS
PISCES
PISCIS
AUSTRINUS SAGITTARIUSSCORPIUS
VIRGO
AltairArcturus
Fomalhaut
Antares Spica
Eta AquaridsMay 6
Piscis Austrinids
Jul 28
Delta AquaridsJul 30
Alpha CapricornidsJul 30
AntihelionMar 15
AntihelionApr 1
AntihelionApr 15
AntihelionMay 1
AntihelionMay 15
AntihelionJun 1
AntihelionJun 15
AntihelionJul 1
AntihelionJul 15
AntihelionAug 1
AntihelionAug 15Antihelion
Sep 1
ecliptic longitude
eclip
tic la
titude
-25˚
-20˚
-15˚
-10˚
-5˚
0˚
+ 5˚
+10˚
+15˚
+20˚
+25˚360˚ 345˚ 330˚ 315˚ 300˚ 285˚ 270˚ 255˚ 240˚ 225˚ 210˚ 195˚ 180˚
+25˚
+20˚
+15˚
+10˚
+ 5˚
0˚
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-25˚ 0h 1 2 h
1 3 h 1 4 h 1 5 h 1 6 h
1 7 h 1 8 h 1 9 h
2 0 h
2 1h
2 2h
2 3h
+ 1 0 o
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e q u a t o r
e q u a t o r
e c l i p t i ce c l i p t i c
Mi
l ky
Wa
y
Coordinates of 2000
METEORS
SUNoverhead
MO
ON
overhead
Qu
ad
ran
tids
ove
rhead
2015 Jan 4 2:00 UT
rota
tion
in o
ne
hour
fligh
t of
the
Earth
1 4 h
1 5 h 1 6 h
+ 4
+ 4 0 o
+ 5 0 o
bNakkar
l
kq
iEdasich
q
c
u
zM
h
Alkaid
Alc
Quadrantid
radiantJu
ne Bootid
s
DRACO
BOOTES
URSA
MAJOR
HER
CU
LES
Astronomical Calendar 2015 61
called June Draconids, derive from Comet 7P Pons-Winnecke, which in its roughly 6-year orbit has mademany returns, some quite close to Earth, though now thecomet’s orbit has moved outward. The peak date has var-ied between June 23 and 27. The radiant is given in north-ern Boötes but also varies; for 40° north it is overhead at9 PM and in the sky all night. There were displays of upto 100 per hour in some past years near the comet’s peri-helion; then after a dormancy of 70 years there was anunexpected outburst in 1998, another in 2004. These tan-talizingly variable meteors can be recognized by theirslowness (“only” 18 km/sec). Moon at First Quarter .
July 28: Piscis Austrinids (July 14–Aug. 10). ZHR maybe as low as 5. The radiant, near Fomalhaut, is in view fornorthern observers only briefly and well after midnight,much longer and higher for the southern hemisphere.
July 30: Delt a Aquarids (July 12–Aug. 23). A diffusestream or group of streams. They are better for southerlyobservers, though for latitude 40° north the radiants are inthe sky most of the night, highest around 2 AM. Two mainsub-streams used to be distinguished, South and North,peaking around July 30 and Aug. 7. But the North DeltaAquarids have been found to be merely part of theAntihelion Source. Delta Aquarids appear sparse,because they are spread widely, but may add up to one ofthe most massive of streams. ZHR at maximum is around20. The meteors are mostly faint, a few bright; 5-10%leave persistent trains; they move medium-slowly, about41 km/sec, because coming in sideways across Earth’sorbit. Moon Full July 31.
July 30: Alpha Capricornids (July 3–Aug. 15).Another diffuse complex, hard to distinguish—except bytheir slow speed of about 23 km/sec—from the DeltaAquarids and the Antihelion Source. They were onceassociated with Comet 72P Denning-Fujikawa, later with45P Honda-Mrkos-Pajdusakova, but the orbits differ toomuch. For mid-northern latitudes the radiant is in the skymost of the night, highest at midnight. Though sparse (5per hour, exceptionally 10), the Alpha Capricornids arephotogenic, being often yellow, often bright, with manyfireballs.
Aug. 13: Perseids (6h; July 17–Aug. 24). The morbidnickname “St. Lawrence’s Tears”—he was martyred on ahot gridiron 258 Aug. 10—may date back only to 1839.Long regarded as our greatest and most reliable shower,later rivaled by the Geminids. Derived from Comet 109PSwift-Tuttle, which (with period around 120 years)appeared in 69 B.C., 188, 1737, 1862, and 1992. Theradiant, in the region where Perseus meets Cassiopeiaand Camelopardalis, is in the sky all night (for northern lat-itudes), at first low in the northeast, overhead toward 6AM. The orbit is steeply inclined to Earth’s (113°, techni-cally retrograde), hence passes near no other planet andis little perturbed. Historical records of the shower go back
to China in AD 36 (when it was in July), Europe in 811; the1866 occurrence was the first for which the link with acomet was made, by Schiaparelli. There were someamazing Perseid outbursts in 1980, the 1990s, and 2004.Numbers seen rise slowly to the peak of 50 or more perhour, then drop faster. Sometimes two peaks have beendistinguished, or more. The meteors are swift, 59 km/sec,which helps to distinguish them from the far less numer-ous Aquarids and Capricornids. Many are bright; white,yellow, green, red, orange; leave spectacular long-lastingtrains; end in flares. There may be an earlier peak, Aug.12 18h, of dust trails from the comet’s 1862 passage.Moon New .
Aug. 14: Kapp a Cygnids (Aug. 6-10). The radiant is(for northern latitudes) much higher than that of thePerseids in the early night, near the zenith around 9 PM.There may be only 3 to 5 per hour, but they are charac-teristically bright, even fireballs, moving slowly (25km/sec).
Sep. 1: Aurigids (14h; Aug. 25–Sep. 10). Discovered in1935 by Cuno Hoffmeister (who later wrote a book onmeteor streams); diminished since to ZHRs up to 5, withoccasional outbursts, the last, in 2007, reaching 130. Thepeak has been on Aug. 31 or Sep. 1 depending on leapdays. The meteors are swift (66 km/sec); many are verybright. They apparently follow the orbit of C/1911 Kiess, along-period comet that will not come by again for morethan a thousand years. The chief radiant is south ofMenkalinan (b Aur); the shower was formerly called AlphaAurigids when the radiant was thought to lie near Capella(a Aur). This area of the sky becomes high only after mid-night and is highest after dawn. The predicted peak timeis after dawn for most of America. Moon just past Full.
Sep. 9: September Ep silon Perseids (22h; Sep. 5-21). Not recognized as an annual shower until an outburston 2008 Sep. 9. The ZHR is given as 5; twice as many ormore may be seen in outburst years. They are swift (64km/sec), often bright. The radiant is nearer to b Persei(Algol) than to e. It is in the sky all night, highest 4 AMlocal time. Waning Moon rises about 2 AM.
Oct. 5/6 : meteors from a radiant in Camelopardalis, pos-sibly, but unconfirmed.
Oct. 9: Draconids (6h; Oct. 6-10) used also to becalled Giacobinids because derived from Comet 21PGiacobini-Zinner, which in its 6.6-year orbit passes closeto Earth’s, last doing so in 2012. The radiant is in theLozenge or head of Draco, only 13° from the north eclipticpole, so that unlike other radiants it scarcely shifts fromday to day. Descending vertically onto the plane of theecliptic, the meteors are slow-moving (20 km/sec). They
typically are faint, and fragment easily. The radiant is highin the early night, low to the northern horizon 3-6 AM. Inmany years no Draconids are seen; but there have beenstrong showers or even storms near the comet’s perihe-lion, such as 1926 (a Draconid fireball “lit up the sky”),1933, 1946 (15 days after the comet passed; up to 10,000an hour seen in the southwestern US in full moonlight),1985, 2005. Waning Moon rises about 3 AM.
Oct. 10: Taurids (Sep. 10–Dec. 10). Complex ofstreams derived from 2P Encke, the comet with the short-est period (3.3 years) and mostfrequent visits. The meteorsradiate from a large area thatmoves eastward along the eclip-tic from Pisces through Aries intoTaurus and is in view throughoutthese nights, highest about midnight. Spread over thistime, they appear sparse on most nights. Because thegeneral orbit lies in the inner solar system, with outer endnear Jupiter, the stream has become perturbed intobranches, which can scarcely be distinguished by thevisual observer. The main ones are the SouthernTaurids , the most abundant, with soft maximum inOctober (till recently it was thought to peak in earlyNovember), and the Northern , with peak Nov. 12. 2015should see a return of the Taurid “swarm” of larger parti-cles, in late Oct. and early Nov., producing higher ratesand fireballs. Taurids appear slow, about 28 km/sec,because they are coming in across our orbit from behind.As the stream goes back out, it encounters Earth’s day-time side and thus produces meteors detectable only asradio showers, the Zeta Perseids and Beta Taurids ofJune.
Oct. 11: Delt a Aurigids (Oct. 10-18). There may ormay not be a real shower, from a radiant at 5h36m +44°.There were past indications, mostly unconfirmed, of sev-eral sparse streams coming from the Auriga-Perseusregion.
Oct. 18: Ep silon Geminids (Oct. 14-27). Minor show-er of very swift meteors (70 km/sec), perhaps derived fromnon-periodic Comet C/1987 B1 Nishikawa-Takamizawa-Tago, whose orbit passed 0.05 AU from Earth’s Oct. 7position (and, on the way out, 0.12 AU from Earth’s July 12position). Up to 3 per hour may be seen, but it is hard toseparate these meteors, radiating from near Mebsuta (eGem), from the more numerous Orionids coming fromtheir nearby radiant. Moon 2 days before First Quarter .
Oct. 21: Orionids (Oct. 2–Nov. 7) are part of thestream coming inward along the approximate orbit ofHalley’s Comet, to be seen on the way out as the EtaAquarids of early May. But because the Orionids’ radiant,in the club of giant Orion near the feet of the Gemini twins,is up throughout a long autumn night for the northernhemisphere (highest at 4 AM), they are more familiar andhave been more fully studied. Orionids are, like the EtaAquarids, swift (66 km/sec); they are sometimes bright,and more than half leave persistent trains. The typicalZHR is 20; it can rise to 70, and sometimes there is morethan one peak, presumably representing thicker clouds ofparticles coming along the orbit. There may also be a 12-year cycle (caused by Jupiter), 2014-16 being a low part.Moon at First Quarter .
Oct. 24: Leo Minorids (Oct. 9-27). Such a weak max-imum (the ZHR is given as 2) that there is small chance ofdetecting them visually. The radiant at 10h48m +37° risesafter midnight and is highest at dawn. Moon 3 daysbefore Full.
ARIES
AURIGA
CANCER
CANISMINOR CETUS
GEMINI
LEO
LEO MINOR
ORION
PERSEUS
PISCES
TAURUS
Capella
Procyon
CastorPollux
Regulus
Betelgeuse
Algol
Aldebaran
AurigidsSep 1
September Epsilon Perseids
Sep 9
Southern TauridsOct 10
Delta AurigidsOct 11
Epsilon GeminidsOct 18
Orionids
Oct 21
Northern TauridsNov 12
Leonids
Nov 17
Alpha MonocerotidsNov 21
MonocerotidsDec 9
SigmaHydridsDec 12
Geminids Dec 14
Coma Berenicids
Dec 16December
Leo Minorids
Dec 20
AntihelionJan 1Antihelion
Jan 15Antihelion
Feb 1Antihelion
Feb 15Antihelion
Mar 1Antihelion
Dec 15
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ay
Pleiades
e c l i p t i c
MONOCEROS
The radiants of most showers mentioned are shown in thisecliptic-based map, and/or the monthly sky maps. Shortlines radiate from the radiants at the peak dates. (Mostactual meteor paths are longer and farther from their radi-ant.) Marks at 1-day intervals show the radiants’ eastwarddrifts during their activity. The persistent AntihelionSource of meteors is represented by approximate positionsof its moving radiant. The smaller charts are at a scale of4 millimeters per degree.
1 8 h
1 9 h
+ 3 0 o
+ 4 0 o
LYRA
q
mxo
n
aVegaz
bShelyak
gSulafat
d
e
k
h
q
LyridsApr 23
Eta LyridsMay 6
June LyridsJun 16
HERCULES
Space-trajectories ofcomet 109P Swift-Tuttleand some of the Perseidmeteors shed from it.
2
3 h
3 h 4 h
4 h
+ 4 0 o
+ 5 0 o
+ 6 0 oCAMELO-
PARDALIS
PERSEUS
DoubleCluster
bAlgol
k
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aMirfakyd
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Sep Epsilon Perseids
Sep 9
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Wa
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62 Astronomical Calendar 2015
For the Northern T aurids , see their Southern sisters inOctober.
Nov. 18: Leonids (4h; Nov. 6-30). The most dramati-cally variable of all. They follow the path of Comet 55PTempel-Tuttle, strike Earth’s atmosphere slightly north ofhead-on (the inclination is 162°) and pierce it at 71km/sec—almost the highest theoretical speed for mete-ors belonging to the solar system. This also means theshower is a morning one: the radiant, in the head of Leo(also called the “Sickle”), rises about 11 PM and is highestabout 6 AM. Leonids are often bright, bluish; most leavepersistent trains. Often only 5 to 20 per hour are seen atthe maximum, but fantastic storms happen usually, but notalways, near the times when the comet comes by in its 33-year orbit, Many were vaguely recorded in early annals(such as 902, Arabic “Year of the Stars”), but it was 1833(thousands per hour, woke people from their beds in east-ern North America) that inspired Denison Olmsted tounderstand radiants and the periodic orbiting of the parti-cles, thus founding meteor science. 1966 Nov. 17(144,000/hour in Arizona, reaching 40 per second!)remains the most intense meteor storm known. Thecomet’s last visit was in 1998, the last storm in 2002. Ifthis year’s peak is at 4h UT, it favors Europe; one expertputs the peak earlier, at Nov. 17 21h. Moon 1 day beforeFirst Quarter .
Nov. 22: Alpha Monocerotids (4h; Nov. 15-25).Usually feeble, with up to 3 swift (65 km/sec) meteors anhour at maximum, but there were brief outbursts in 1925,1935, 1985, and especially 1995: a 30-minute show with a5-minute climax from which was calculated a ZHR of 420.There may not be another outburst for a long time. Theradiant, now in Canis Minor rather than Monoceros, is inthe sky after 11 PM and highest at 4 AM. The peak timewould put the radiant overhead for Europe. Moon 3 dayspast First Quarter .
Dec. 6: Phoenicids (22h; Nov. 28–Dec. 9). The radiant is53° south, in Phoenix but just northwest of Achernar (aEridani), so this is for south-hemisphere observers. Theshower made its astonishing debut on 1956 Dec. 5: first R.Lynch in New Zealand, then others in Australia, the IndianOcean, and South Africa, saw up to 100 per hour, manyexploding as fireballs brighter than Venus. Since thenthey have been recorded only in scattered years, withpeak rates from 2 to 5. They move slowly (18 km/sec). Itwas soon realized that they are debris from 289PBlanpain, which after its 1819 discovery was “the long-lostcomet” (despite an only 5.1-year orbit), yet was rediscov-ered by stages from 2003 to 2013, and returned to peri-helion in 2014. Moon 3 days p ast Last Quarter .
Dec. 7: Puppids (Dec. 1-15). A diffuse and vaguelyknown group of streams with as many as 10 radiants in a20°-wide area of Puppis, Vela, and Carina. (So they mightbe called the “Argonauts.”) Up to 10 meteors per hour(some very bright) may be seen from the southern hemi-sphere.
Dec. 9: Monocerotids (Nov. 27–Dec. 17). Medium-
speed (42 km/sec) meteors derived from Comet C/1917F1 Mellish (discovered 1917, not to return till 2062). Theirradiant, 8° south of the celestial equator, is in view most ofthe night (highest 1 AM) for both hemispheres; but theyare very sparse (maybe 2 per hour at most) and difficult toseparate from the Geminids already starting. Moon 2days before New .
Dec. 12: Sigma Hydrids (Dec. 3-15). Sparse (up to 9an hour but more typically 3), faint, swift (58 km/sec) mete-ors from a radiant, just north of the equator, near the headof Hydra, that rises not long before midnight and is high-est at 3 AM. Various studies have given their peak as Dec.6, 12, or 14.
Dec. 14: Geminids (Dec. 4-17) have since about 1960surpassed the Perseids as most reliable among the annu-al showers. Instead of a sharp peak they have a “plateau,”this year from Dec. 14 1h to 23h, during which from 50 to130 an hour may be seen. Their radiant, near Castor, isup for almost all of the long (northern) winter night, high-est at 2 AM (so I once did a “star vigil,” logging Geminidsand waiting for the constellations that first set to comeback around into view). Geminids are medium-slow (35km/sec) because coming sideways into Earth’s orbit.Their long-sought parent body was discovered in 1983 bymeans of the IRAS satellite, and is not a comet but,uniquely, an asteroid: 3200 Phaethon, 5 km wide, with a1.52-year orbit, shorter than any comet’s, passing overEarth’s orbit by less than 1/10 of the Moon’s distance (theasteroid’s next close approach will be in 2017) and thendipping 3 times nearer than Mercury to the Sun. Thisrocky origin explains the nature of the Geminids: mostlybright, very few leaving trains. Moon only 3 days p ast
New.
Dec. 16: Coma Berenicids and December LeoMinorids (Dec. 12-23). These may be one shower or tworesulting from sub-streams of one stream—experts havechanged their minds as to whether they can be separated.If they can, the former may peak about Dec. 16, and thelatter, slightly more abundant, about Dec. 20. Both yieldonly up to 3 meteors an hour, faint and swift (65 km/sec).The radiant in Leo Minor, the obscure constellation aboveLeo’s back, rises about 10 PM and is up the rest of thenight; Coma Berenices (which was once, according tostory, the tuft on Leo’s tail) is 30° southeast, thus risesafter midnight (for northern observers). Over this time theMoon is from 5 to 9 days old.
Dec. 23: Ursids (2h; Dec. 17-26) radiate from nearKokab, the b star of Ursa Minor, at the other end of theLittle Dipper from Polaris. They were also called (beforenames were regulated by the International AstronomicalUnion) Ursa-Minorids or Umids. This radiant is (for lati-tude 40° north) in the sky all night, 26° above the northhorizon in the early night, almost overhead by dawn.These interesting meteors, filling the long cold winter-sol-stice night, are under-observed; it could be an even bettercandidate for a Star Vigil than the night of the Geminids!The parent comet is 8P Tuttle, which at intervals of 13½years drops steeply from the north through a perihelionclose to Earth’s orbit; it last came by in January 2008.(Comet and meteors revolve almost in the plane of theMilky Way, though in the opposite direction to that of thestars.) The meteors are of medium speed (33 km/sec),mostly faint but with a few fireballs; during the shower’sbrief peak 9 or 10 per hour may be seen, up to 50 espe-cially when the comet is near; in 1945 and 1986 the ratewas over 100. If the peak is as predicted around 2h UT, itwill be early night for America, past midnight for Europe.Moon 2 days before Full.
SUN
MO
ON
Geminids
2015 Dec 1412:00 UT
SUN
overh
ead
MOON
Leonids
2015 Nov 17 4:05 UT
In these globe diagrams, “radiant overhead” is only oneline, probably far from central, in the particle stream,which is vastly wider than the Earth.
5 5 P T e m p e l -
1 P H a l l e y
Leonids
SW3ids
E a r t h
Sun
Quad
rantids
Lyrids
Eta A
quarid
s
Perseid
s
Orionids
Gem
inid
s
Urs
ids
Oct
NovDec
JanSep
Aug
Jul
Jun
May
Apr
Mar
Feb
1 P H a l l e y
T u t t l e
Paths of some streamsin space (blue when south of
the ecliptic plane) and some of their parent comets.
The Perseid meteors and the comet fromwhich they were shed, 109P Swift-Tuttle.The comet was discovered in 1862 butGary Kronk has found that it was seenby the Chinese in 69 B.C. and A.D.188; it is in a 135-year orbit ofhigh retrograde inclination(114°), which comes close toEarth’s and is locked in a1:11 orbital resonancewith Jupiter; it waslast at perihelion(0.958 a.u.from the
Sun) on1992 Dec.
12. The meteorstream, or rather the part of
it that hits Earth, is suggested by particles trav-eling along five “strands,” in each of which one orbital ele-ment—the longitude of perihelion—is increased or reducedby one or two degrees, as if the particles separated from thecomet somewhat before or after its perihelion. This results inthe particles being increasingly (away from perihelion) spreadout in the plane of the orbit, which is roughly what happens inan actual meteor stream. The stream is really far wider, butthe Earth collides with only a tiny fraction of it. The meteorsare shown blue where they are south of the ecliptic plane; thetransition between gray and blue is where we see the meteors.
perihelion
E a r t h
1
09P
Sw
i ft-Tu
t t le
Pers
eids
Sun
Jan
Dec
1992
Nov
Sep
Jul
AugOct
Dec
These charts are of the zodiacal band—the zone aroundthe sky within which the Sun, planets and Moon move. (Theband shown is 40° wide, centered on the ecliptic.) Arrowsshow the planets’ courses during each month.
The Sun is shown at the 1st, 16th, and last day of themonth; its disk is exaggerated 8 times in apparent size. Atthe middle of the month, its glare is indicated schematically.
The Moon is shown for each date at 0h Universal Time(Greenwich midnight). For local midnight at longitude 75°west (in America’s Eastern time zone) it will be 5/24 of theway east (left) toward the next date’s position; for the
Central, Mountain, and Pacific zones, 6/24, 7/24, and 8/24of the way. Its position is as seen from the center of theEarth, i.e. not adjusted for parallax. From a northern lati-tude it will be displaced slightly south. Its size is exaggerat-ed 8 times; it appears slightly larger near perigee (such asJan. 21) than apogee (such as Jan. 9). Gray areas are thedark maria (“seas”). We sometimes show stars and planetsin front of the Moon, which, being exaggerated insize, would otherwise hide them much moreoften than it really does.
68 Astronomical Calendar 2015
AQUARIUS
CAPRICORNUS
LIBRA
PISCES
SAGITTARIUS
SCORPIUS
VIRGO
OPHIUCHUS
Altair
Arcturus
FomalhautAntares
Spica
Jan 12Moon
13Last Quarter
14
15
16171819
20
21New
22
23
24
Mercury
Venus
Mars
Saturn
Neptu
ne
Pluto
e c l i p t i c
e q u a t o r e q u a t o r
Mi
lk
y
Mi
lk
y
Wa
y
Wa
yAQUARIUS
CAPRICORNUS
LIBRA
PISCES
SAGITTARIUS
SCORPIUS
VIRGO
OPHIUCHUS
Altair
Arcturus
Fomalhaut
Antares
Spica
Feb 8M
oo
9
10
11
12Last Quarter
13141516
17
18
19New
20
21
Mercury
Venus
Mars
Saturn
Neptune
Plutoe c l i p t i c
e q u a t o re q u a t o r
Mi
lk
y
Mi
lk
y
Wa
y
Wa
y
AQUARIUS
CAPRICORNUS
LIBRA
PISCES
SAGITTARIUS
SCORPIUS
VIRGO
OPHIUCHUS
Altair
Arcturus
Fomalhaut
Antares
Spica
Mar 8
9
10
1112
1314Last Quarter
1516
17
18
19
20New
TOTALSOLARECLIPSEMar 20
MercurySatu
rn
Neptune
Pluto e c l i p t i c
e q u a t o re q u a t o r
Mi
lk
y
Mi
lk
y
Wa
y
Wa
y
AQUARIUS
CAPRICORNUS
LIBRA
PISCES
SAGITTARIUS
SCORPIUS
VIRGO
OPHIUCHUS
Altair
Arcturus
Fomalhaut
Antares
Spica
Apr 16
Apr 1
Apr 16
30
Apr 4
5Full
6
78
9101112
Last Quarter13
14
15
16
May 1
TOTAL
lunar
ECLIPSE
Apr 4
Saturn
Neptune
Pluto
e c l i p t i c
e q u a t o re q u a t o r
Mi
lk
y
Mi
lk
y
Wa
y
Wa
y
AQUARIUS
CAPRICORNUS
LIBRA
PISCES
SAGITTARIUS
SCORPIUS
VIRGO
OPHIUCHUS
Altair
Arcturus
Fomalhaut
Antares
Spica
Apr 16Apr 16
May 1
2
3
4Full
56789
10
11
Last Quarter
12
13
14
28
29
30
31
Jun 1
Saturn
Neptune
Plutoe c l i p t i c
e q u a t o re q u a t o r
Mi
lk
y
Mi
lk
y
Wa
y
Wa
y
AQUARIUS
CAPRICORNUS
LIBRA
PISCES
SAGITTARIUS
SCORPIUS
VIRGO
OPHIUCHUS
e c l i p t i c
e q u a t o re q u a t o r
Mi
lk
y
Mi
lk
y
Wa
y
Wa
yAltair
Arcturus
Fomalhaut
Antares
Spica
12
3Full
456
7
8
9
10LastQuarter
Jun 25
26
27
2829
30Jul 1
Saturn
Neptune
Pluto
First
Quarter
ZODIAC CHARTS
January
February
March
April
May
June
Libration is shown in these charts by red tabs on the Moon.Each is at the place on the Moon’s limb (edge) most libratedtoward us, and its outward width is proportional to the amount ofthe libration. At and near this place you can see with your tele-scope a few degrees past the average horizon into the foreshort-ened features of the Luna Incognita (“unknown Moon”) on our
neighbor small planet’s far side. But if the place is on the dark halfof the limb, where you can’t see anything, the libration is of noadvantage; this is indicated with a tab of paler color. The libration-spot is always on the hemisphere nearer to the ecliptic, becausewhen the Moon is south of the ecliptic plane we are looking slight-ly “down” on it—its north pole is in view—and vice versa.
Astronomical Calendar 2015 69
ARIES
CANCER
GEMINI
LEO
TAURUS
CETUS
ORION
Capella
Sirius
Procyon
Castor
Pollux
Regulus
Rigel
Betelgeuse
Algol
Aldeb
aran
M35
Jun 11
Moon
12
13
14
151617
New1819
20
21
22
23
24
VenusMars
Jupiter
Uranus
e c l i p t i c
e q u a t o re q u a t o r
Mi
lk
y
Mi
lk
y
Wa
y
Wa
y
Beehive
Pleiades
PISCES
Mercury
ARIES
CANCERGEMINI
LEO
TAURUS
CETUS
ORION
Sirius
Procyon
Castor
Pollux
Regulus
Rigel
Betelgeuse
Algol
Aldebaran
M35
May 15
Moon
16
17
18New
202122
23
24
25
26
First Quarter
27
MercuryVenus
MarsJupiter
Uranus
e c l i p t i c
e q u a t o re q u a t o re q u a t o r
Mi
lk
y
Mi
lk
y
Wa
y
Wa
y
Pleiades
Beehive
19
PISCES
ARIES
CANCER
GEMINI
LEO
TAURUS
CETUS
ORION
Sirius
Procyon
Castor
Pollux
Regulus
Rigel
Betelgeuse
Algol
Aldebaran
M35
Apr 1
2
3
Apr 17
Moon
18
19New
2021
22232425
26
First Quarter27
28
2930
Mercury
Venus
MarsJupite
r
Uranus
e c l i p t i c
e q u a t o re q u a t o r
Mi
lk
y
Mi
lk
y
Wa
y
Wa
y
Pleiades
Beehive
PISCES
ARIES
CANCER
GEMINI
LEO
TAURUS
CETUS
ORION
Sirius
Procyon
Castor
Pollux
Regulus
Rigel
Betelgeuse
Algol
Aldebaran
M35
Mar 16
Mar 12
3
4
5
6Full
7Mar 21
Moon
22
23
24252627
First Quarter2829
30
31
Apr 1
Venus
Mars
Jupiter
Uranus
e c l i p t i c
e q u a t o re q u a t o r
Mi
lk
y
Mi
lk
y
Wa
y
Wa
y
Pleiades
Beehive
PISCES
ARIES
CANCER
GEMINI
LEO
TAURUS
CETUS
ORION
Sirius
Procyon
Castor
Pollux
Regulus
Rigel
Betelgeuse
Algol
M35
Feb 12
34Full5
6
7
Feb 22M
oon
23
24
2526
First Quarter2728Mar 1
Jupiter
Uranus
e c l i p t i c
e q u a t o re q u a t o r
Mi
lk
y
Mi
lk
y
Wa
y
Wa
y
Pleiades
Beehive
PISCESAldebaran
ARIESCANCER
GEMINI
LEO
TAURUS
CETUS
ORION
Sirius
Procyon
Castor
Pollux
Regulus
Rigel
Betelgeuse
Algol
M35
Jan 1Moon
2345
Full67
8
9
10
11
Jan 25
26
27
First Quarter
2829
3031Feb 1
Jupiter
Uranus
e c l i p t i c
e q u a t o re q u a t o r
Mi
lk
y
Mi
lk
y
Wa
y
Wa
y
Pleiades
Beehive
Aldeb
aranH
yades
PISCES
The Moon and planets pass through the twelve constellationsof the traditional zodiac plus Ophiuchus, and some of themcan also wander southward into Cetus, Orion, Hydra,Sextans, Corvus, and Crater, or northward into Auriga,Scutum and Pegasus. Pluto can enter Eridanus, ComaBerenices, Serpens (Caput), Serpens (Cauda), and Boötes,and other minor bodies with high inclinations can be inany constellation. (See Jean Meeus, MoreMathematical Astronomy Morsels, p. 333.)
The zodiacal charts are handy for surveying the state of the sky. “Night” isfrom the Sun leftward and all the way back around to the Sun.
Starting at the Sun, you see to its left the stars and planets that are lowin the evening sky and about to set after it; leftward from them, the bodiesthat are prominent in the early night; leftward again, those that are at or nearopposition (including the Full Moon); leftward again, the morning sky, andfinally to the Sun’s right are the bodies that rise in twilight just before it.
70 Astronomical Calendar 2015
AQUARIUS
CAPRICORNUS
LIBRA
PISCES
SAGITTARIUS
SCORPIUS
VIRGO
OPHIUCHUS
e c l i p t i c
e q u a t o re q u a t o r
Mi
lk
y
Mi
lk
y
Wa
y
Wa
yAltair
Arcturus
Fomalhaut
Antares
Spica
Jul 123
4
5
6
7
Jul 22
23
24
25
2627
28293031
Aug 1
Full
First
Quarter
Full
Saturn
Neptune
Pluto
AQUARIUS
CAPRICORNUS
LIBRA
PISCES
SAGITTARIUS
SCORPIUS
VIRGO
OPHIUCHUS
e c l i p t i c
e q u a t o re q u a t o rM
il
ky
Mi
lk
y
Wa
y
Wa
yAltair
Arcturus
Fomalhaut
Antares
Spica
Aug 1
2
3Aug 18
19
20
21
2223
24252627
28
29
30
31
FirstQuarter
Full
Saturn
Neptune
Pluto
AQUARIUS
CAPRICORNUS
LIBRA
PISCES
SAGITTARIUS
SCORPIUS
VIRGO
OPHIUCHUS
e c l i p t i c
e q u a t o re q u a t o r
Mi
lk
y
Mi
lk
y
Wa
y
Wa
yAltair
Arcturus
Fomalhaut
Antares
Spica
Sep 15
16
17
1819
20212223
24
25
26
27
First Quarter
Merc
ury
Saturn
Neptune
Pluto
AQUARIUS
CAPRICORNUS
LIBRA
PISCES
SAGITTARIUS
SCORPIUS
VIRGO
OPHIUCHUS
e c l i p t i c
e q u a t o re q u a t o r
Mi
lk
y
Mi
lk
y
Wa
y
Wa
yAltair
Arcturus
Fomalhaut
Antares
Spica
Oct 1213
New
14
15
1617
18192021
22
23
24
25
New
FirstQuarter
Mercury
Saturn
Neptune
Pluto
AQUARIUS
CAPRICORNUS
LIBRA
PISCES
SAGITTARIUS
SCORPIUS
VIRGO
OPHIUCHUS
e c l i p t i c
e q u a t o re q u a t o r
Mi
lk
y
Mi
lk
y
Wa
y
Wa
y
Nov 8
9
10
11
1213
14151617
18
19
20
21
New
FirstQuarter
Altair
Arcturus
Fomalhaut
Antares
SpicaMercury
Venus Mars
Saturn
Neptune
Pluto
AQUARIUS
CAPRICORNUS
LIBRA
PISCES
SAGITTARIUS
SCORPIUS
VIRGO
OPHIUCHUS
e c l i p t i c
e q u a t o re q u a t o r
Mi
lk
y
Mi
lk
y
Wa
y
Wa
y
Dec 5
6
7
8
910
11121314
15
16
17
18
New
First Quarter
Altair
Arcturus
Fomalhaut
Antares
Spica
Mercury
Venus
Mars
Saturn
Neptune
Pluto
July
August
September
October
November
December
Astronomical Calendar 2015 71
ARIES
CANCER
GEMINI
LEO
PISCES
TAURUS
CETUS
ORION
e c l i p t i c
e q u a t o re q u a t o r
Mi
lk
y
Mi
lk
y
Wa
y
Wa
y
Dec 1
2
3
4
Dec 19
20
21
22
2324
252627
28
29
30
31
2016
Jan 1
Last
QuarterFull
Sirius
Procyon
Castor
Pollux
Regulus
Rigel
Betelgeuse
Algol
Ald
ebaran
M35
Ura
nus
Pleiades
Beehive
Jupiter
ARIES
CANCER GEMINI
LEOPISCES
TAURUS
CETUS
ORION
e c l i p t i c
e q u a t o re q u a t o r
Mi
lk
y
Mi
lk
y
Wa
y
Wa
y
Nov 123
4
5
6
7 Nov 22
23
24
25
26272829
30
Dec 1
Last
Quarter
Full
Sirius
Procyon
Castor
Pollux
Regulus
Rigel
Betelgeuse
Algol
Aldebaran
M35
Jupite
r
Uranus
Pleiades
Beehive
ARIES
CANCERGEMINI
LEOPISCES
TAURUS
CETUS
ORION
Oct 1
e c l i p t i c
e q u a t o re q u a t o r
Mi
lk
y
Mi
lk
y
Wa
y
Wa
y
Sirius
Procyon
Castor
Pollux
Regulus
Rigel
Betelgeuse
Algol
M35
Oct 12
3456
78
9
10
11
Oct 26
27
28
293031Nov 1
LastQuarter
Full
VenusM
ars
Jupite
r
Uranus
Pleiades
Aldeb
aran
Beehive
ARIES
CANCERGEMINI
LEOPISCES
TAURUS
CETUS
ORION
Sep 30
e c l i p t i c
e q u a t o re q u a t o r
Mi
lk
y
Mi
lk
y
Wa
y
Wa
y
Sirius
Procyon
Castor
Pollux
Regulus
Rigel
Betelgeuse
Algol
Aldebaran
M35
Sep 1
2
3
4
6789
10
11
1213
1428
Full29
30
Oct 1
LastQuarter
New
partial
SOLAR
ECLIPSE
Sep 13
TOTALlunarECLIPSESep 28
Venus
Mars
Jupite
r
Ura
nus
Beehive
Pleiades
5
ARIES
CANCER
GEMINI
LEO
TAURUS
CETUS
ORION
e c l i p t i c
e q u a t o re q u a t o r
Mi
lk
y
Mi
lk
y
Wa
y
Wa
y
Sirius
Procyon
Castor
Pollux
Regulus
Rigel
Betelgeuse
Algol
M35
Aug 4
5
6
78
10111213
14
15
16
17 Sep 1
Last QuarterNew
Merc
ury
Venus
Mars
Jupiter
Uranus
Beehive
Pleiades
9 Aldebaran
PISCES
ARIES
CANCER
GEMINI
LEO
TAURUS
CETUS
ORION
e c l i p t i c
e q u a t o re q u a t o r
Mi
lk
y
Mi
lk
y
Wa
y
Wa
y
Sirius
Procyon
Castor
Pollux
Regulus
Rigel
Betelgeuse
Algol
Aldebaran
M35
Jul 1
Jul 8
9
10
11
1213
141516
1718
1920
21
LastQuarterNew
Mercury
Venus
Mars
Jupiter
Uranus
Pleiades
BeehivePISCES