BY DAVE GILL

The cycle of the seasons has brought us aroundto spring once again. The grass is greening up. Weare teased by warm days followed by cold relapses.But on the warm days of early spring, we aretempted to open the windows and let in the freshair. Likewise, we open up the window on the uni-verse in the spring – looking out the top of theMilky Way where the dust is thin. We get a view ofthe distant neighborhoods like the Virgo and Comaclusters of galaxies. Spring is galaxy season. Getout and drink in some ancient light!

The first few months of 2003 have been verybusy for us. In part because of joint promotionwith Hoover-Price Planetarium for the appearanceof Saturn, we have had really good crowds for ourpublic nights. The March night was good – withabout 45 visitors. But February…. We had nearly100 guests! Thanks to all who have been comingout and manning telescopes, giving programs orjust helping with answering questions and manag-ing traffic flow. It shows once again the greatpotential we have to reach the public with astron-omy education. We also had three successful out-reach programs in March – at Inspiration Hills,Clearmount School, and Midvale. Thanks to Johnand his crew of usual suspects with warm heartsand cold feet.

We are experiencing a “changing of the guard”in the club. All TWC clubs have a member ofTWC’s staff as a liaison between the club and TWC.This person handles all sorts of issues for the club,usually involving scheduling, helping to negotiateunusual requests, etc. The WCAC has been fortu-nate to have Joann Ballbach as our liaison for 15years – I think she acted in that role even beforethere was an official “position” as liaison. But ourrelationship with Joann has run much deeper thanthat. Many of us consider her a close friend. Manyof us have helped her in her role as EducationDirector – whether in developing programs, actingas a volunteer, or (in John’s case) having Joann asa customer (who he has taken special care of). Inreturn we have also got special treatment. Joannhas, of her own volition, been a paying member ofthe WCAC. She worked with us through the diffi-cult times we had in getting the AEB built and

AAtt PPrriimmee FFooccuuss

Vernal Equinox, 2003

continued on page 2

Inside HorizonUnder Distant Skies . . . . . . . . . . page 3

Choosing a CCD Camera . . . . . . page 6

Review, Apogee Widestar 80 . .page 9

Parallax, Serendipityand the Comet of 1577 . .page 11

May 15/16 Total Lunar Eclipse . page 13

Landscapes of the Spirit . . . . . . page 15

Variables in Corona Borealisand Bootes . . .page 16

And More!

started up. Well, Joann decided she wanted a bit ofa change. With recent turnover in TWC staffing,there was need for some new liaison relationships.Joann is taking on the Nature Photo Club. And weare adopting Tammy Seikel as our new liaison.Tammy is no stranger to TWC – she has beenactively involved as part-time staff for a number ofyears involved mostly in the annual EarthlyDelights auction. She recently took HowardRubin’s place as Development Director. So, wewant to offer Tammy a big WCAC welcome. Pleaselet us know what we can do to help you out. At thistime in our history, it is good that we have thischance to cultivate a close relationship with youbecause we need your help to finish the KellerTelescope. And Joann – please don’t be a stranger.We know that we’ll still be working with you onoutreaches and other educational activities. Butwe sure hope you’ll come around to meetings andstarwatches, too, because it isn’t just your role welike – it is YOU.

We elected officers for the next 12 months atthe March meeting. Bill Castro, Gene Rickenbrodeand Dave Gill return as President, VP, andTreasurer. Norma Breehl joins the officers asSecretary. Welcome aboard, Norma! And manythanks to Christopher Buehler for his year as sec-retary. You did a nice job. We wish you all the bestas you head for college next fall.

Odds ‘n’ EndsPlease see inside for our upcoming programs –

we have a couple outside speakers coming in Apriland May… If anyone has a crazy idea about takinga college astronomy course, I’ll be teaching PH 120– “Astronomy: A Survey” at Mount Union this sum-mer – two nights a week for 8 weeks…. We’re par-ticipating in a TWC “Clubs Open House” onSunday, May 4th from 1-5. We can use all kinds ofhelp. Please contact John Waechter to volunteer…Jim Quinn and Rick Breehl have been training touse the planetarium, and are about to be turnedloose – go get ‘em, boys. And Dave Ross has beenfussing around making a new projector dog houseto mount digital or slide projectors to project intothe dome…. And Dave has been working to helprelieve indoor light pollution by finding legal meth-ods to temporarily extinguish the exit light in the

Silk Planetarium. Stay tuned…. Welcome to newmembers Steve & Judy Kramer, Gerald & RochelleKramer (no connection as far as I know), BrianGray, and Steve Lenarz… Gotta go – See you at astar watch, a meeting or other event!

Da Editor

HHOORRIIZZOONN is the quarterly newsletter ofThe Wilderness Center Astronomy Club.

Editor: . . . . . . . . . . . . . . . . . . . . Dave Gill

Contributors: . . . . Bill Castro, Phil Hoyle,Dave Ross, John Weiss,

Ralph Geschwind

Layout & Printing . . . . . . . John Waechter

WWCCAACC OOffffiicceerrss::

President: . . . . . . . . . . . . . . . . . Bill CastroVice President: . . . . . . Gene RickenbrodeSecretary: . . . . . . . . . . . . . . Norma BreehlTreasurer: . . . . . . . . . . . . . . . . . Dave Gill

Program Director: . . . . . . . . . . Dave RossPlanetarium Coordinator: . . . . Dave RossObservatory Coordinator: .John WaechterEducation Outreach: . . . . John Waechter

WWCCAACC AAddddrreessss::P.O. Box 202

Wilmot, Ohio 44689-0202

Web Site: http://www.twcac.org

H O R I Z O N2

BY DAVE ROSS

Whatever is in the heavens and on earth,Let it declare the Praises and Glory of Allah…He knows what enters within the earth and

what comes forth out of it,What comes down from heaven and what

mounts up to it.(Koran 57)

Each year more than two million Muslims fromall parts of the world undertake the pilgrimage toMecca known as the Hajj. The fifth pillar of Islamis the obligation for the believer, in so far as he orshe is able, to visit the holy city and pray before“the house of Allah,” the Kaaba. The word meanscube, which roughly describes the ancient granitebuilding which is considered the holiest sanctuaryin all Islam.

The Hajj is a celebration that takes place in the12th month in the Muslim lunar calendar over aperiod of just a few days. But, when Muslims any-where make their daily prayers they turn and bowin the direction of Mecca, determined by calcula-tion or the observation of certain celestial eventsand called the Qiblah, in order to align themselveswith the spiritual power that emanates from theKaaba. It is the cosmic center of their religion.Not surprisingly, as with other examples of the axismundi encountered in many other cultures, thecosmic center at the Kaaba is marked by astro-nomical alignments and by the presence of asacred object that is believed to bridge Heaven andearth. The Northeast wall of the Kaaba faces theSummer solstice sunrise. Its Southeast wall facesthe place where Canopus, second only to Sirius inbrilliance, rises on the horizon. And at theSoutheast corner the well known Black Stone ofthe Kaaba is set in its silver frame. It has oftenbeen described as being a meteorite.

When pilgrims arrive at the Kaaba for the Hajjthey walk in prayer circling counterclockwisearound the draped sanctuary seven times. Thenumber is an ancient symbol of cosmic wholeness.With each circuit they make their way closer to the

Kaaba until they are able to salute the stone bytouching it, kissing it or, if nothing else is possible,greeting it with a reverent gaze.

The prophet Mohammed, founder of Islam, issaid to have overseen the erection of the Kaaba,which Muslims believe to be a restoration of a tem-ple originally built on the site by the patriarchAbraham in honor of the birth of his son Ishamel,ancestor of the Arab peoples. Abraham’s altar wasitself a restoration of one built by Adam and Eve.The angel Gabriel delivered the stone to Abraham,which was originally white, as a gift from Heaven toserve as the cornerstone. In the faith of Islam it isa heaven sent stone, whether or not it happens tobe an actual meteorite, and it continues to serve asthe symbol of Islamic identity and unity.

The second century Christian theologianClement of Alexandria, writing some four hundredyears before Mohammed, commented on the Arabpeoples being great worshippers of stones. Suchsacred stones were given the name “baetyl” stones,

H O R I Z O N 3

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The Black Stone of the Kaaba in its silver frame atthe SE corner of the sanctuary. The stone is

actually bound in mortar as it has been brokenover the centuries. Although very dark some say

the stone is also tinged with red. Even stonymeteorites contain enough iron to rust. Much of

the lore surrounding the stone suggests a meteoritebut there is no conclusive evidence to say for

certain. The stone has no doubt been smoothedand stained by centuries of human touch.

from the Hebrew Beth El, “House of God,” as in thestory of Jacob’s dream. So it seems reasonable tospeculate that the Kaaba stone may indeed be anobject venerated by untold generations. Islamiclegend accounts for this by claiming that afterAbraham his temple at Mecca fell into the hands ofidol worshippers until the time of Mohammed,whose prophetic mission was to unite the tribalfactions of the Arabian peninsula under the wor-ship of the one true God, Allah. The white stonehad over the course of those long centuries turnedblack with the stain of human sins. Indeed, this ispart of its function in the religion of Islam.Pilgrims pray that by touching the stone they willexperience release from their sins and be granted afresh start as they return to their daily lives afterthe Hajj.

Since the founding of Islam in the 7th centuryA.D. the stone has apparently been physicallyattacked, stolen, and temporarily lost. As seentoday the stone is in fragments held together withmortar. Whatever the stone is it cannot be an ironmeteorite. But a stony meteorite cannot be ruledout. Stony meteorites can be fractured and aresometimes light in color underneath a darkenedfusion crust that forms with the heat of enteringearth’s atmosphere at cosmic velocities.

Since non-Muslims are strictly barred (and weknow what that means, historically!) from Mecca,let alone from approaching the Kaaba, the fewdescriptions that circulated down to the nine-teenth century were sketchy at best. Since then,Muslim writers have themselves commented of thestone’s history and appearance. But no reliablescientific investigation has ever been permittednor is one likely anytime soon. Other Islamic leg-ends about the stone relate how it was once recov-ered after being stolen because of a rather unusualproperty. It floats on water! Meteorites can drawa magnet, but float on water? If the Kaaba stonemust really answer to all that is said about it, more

recent writers tend to discount descriptions of it asa meteorite. But there may still be a connection.

In the 1930’s the British explorer, Harry St.John Philby, went to Arabia in search of the lostcity of Ubar, destroyed by Allah in ancient timesSodom and Gomorrah style. Guides showed him aplace in the Empty Quarter of Eastern Arabia thatlocal peoples claimed was the site. Philby found noruins to suggest a city, but what he did find was acircular structure and strange iron bearing rocks.He came to believe it was the site of a meteoriteimpact, confirmed by later tests on samples hereturned to England. Those early tests suggestedan age of 6000 years.

In 1995, the world’s preeminent impact scien-tist, Eugene Shoemaker, accompanied geologistJeffery Wynn on an expedition to study Philby’scrater, dubbed Wabar. They found two circularfeatures that were partly hidden by the shiftingdunes. In the crater rims they found what theydescribed as a “fallout deposit of glassy black slag.”Such material is called impactite, a product of thehigh temperatures and shock that accompanymeteorite impacts. Some speculate that impactite,if frothy with enough bubbles of trapped gas, mightfloat on water in the manner of volcanic pumice.

H O R I Z O N4

The alignments of the Kaabaare illustrated here with

respect to the four winds.Medieval texts specifically

mention the alignments withthe solstice and the rise pointof Canopus and have beenconfirmed in modern times.

Searching for the lost city of Ubar, Philby stumbledupon the impact site he names Wabar, about 340miles Southeast of Riyadh, the capital city of SaudiArabia. An ancient ruin in northern Oman is now

believed to be the lost city.

Mystery solved? Who can say? By its verynature the Black Stone of the Kaaba remains tan-talizingly unapproachable. Shoemaker and Wynnsuggested a more realistic age for the Wabar cratersbetween 100 and 400 years. Such fragile featureswould be obliterated beneath the sands if mucholder. This would not be old enough to fit the tra-dition of the Black Stone’s great age. But, who’s tosay some earlier event, lost to the sands of time,didn’t once rock the trackless wastes of theArabian desert and produce a unique and unusualstone that tribesmen treasured as a gift fromabove?

(The stain of human sin… The stone mustsurely be black indeed! Which leaves us wonder-ing why the Hajj is only held for those few days inthe 12th lunar month, Dhul-Hijah; why not extendthe hours to accommodate the anticipated longlines? The most recent festival was held February10-13th, 2003. Since the lunar calendar precess-es backward, next year’s Hajj is set for January30th – February 2nd. But, since this is a strictlylunar calendar everything depends on an actualsighting of the crescent moon. Whereas in theChristian West it was the date for Easter thathelped keep Medieval astronomy and mathemat-ics alive during the Dark Ages, in the Islamic Eastit was the calculation of the Qiblah, the sacredline of Mecca, that concentrated much of theirscholarly attention. As Mr. Weiss’ fine article lastFall in these pages notes, Western civilizationremains in their debt in many ways, this morerecent time of troubles not withstanding.

–The Demiurge)

H O R I Z O N 5

A frothy piece of impact slag from Wabar. From:Meteorites: A Journey through Space and Time by

Alex Bevan and John de Laeter (2002).

UUppccoommiinngg PPrrooggrraamm UUppddaatteess!!Please note the following changes to previously announced meeting programs:

April 25 - “Ion Propulsion and Future Outer Planet Exploration Missions” presented by Scott Benson from NASA’s Glenn Research Center

May 30 - “Thermal Management in Newtonian Telescopes” – Bryan Greer

June 27 - “Show and Tell” – Bring and share your latest gadgets, gear and books

H O R I Z O N6

BY BILL CASTRO

Many articles talk about what scope works bestwith a given camera. Since most of us already owna scope, this article discusses selecting a camera towork best with an existing scope.

The goal of the scope and camera combinationis to optimize the amount of sky coverage eachcamera pixel sees with the object you are trying toimage. This gets into sampling theory that is dis-cussed in detail in the references below. The basicequation for this is expressed in arc-sec/pixel. Thisequation is derived form the relationship of an arclength being the product of the radius of an arctimes the angle (expressed in radians). The equa-tion is:

Arc-sec/pixel = 206.265 * pixel size /focal length (1)

Where 206.265 is converting radians to angularmeasure, pixel size is in micro-meters (µ) and focallength is in (mm). I will leave the derivation of thisas an exercise to the math enthusiast. This approx-imation is good for focal lengths of 200mm orgreater. Not a problem with most telescopes.

The field of view of a camera is:

FOV = arc-sec/pixel * the number of pixels in that direction (2)

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My Stellacam CCD camera has the following:

HHoorriizzoonnttaall – 768 pixels and 8.4µ pixel size in thehorizontal direction.

VVeerrttiiccaall – 492 pixels and 9.8µ pixel size in the ver-tical direction.

Matched to a telescope with a 2000 mm focallength (my 8 inch SCT) results in:

The horizontal resolution is:

Arc-sec/pixel = 206.265 * 8.4 / 2000 = 0.866 arc-sec/pixel

The horizontal field of view is

0.866 arc-sec/pixel * 768 pixel = 665 arc-sec

To convert to arc minutes:

665 arc-sec / 60 = 11.09 arc-minutes.

Similarly the vertical resolution & field of view is:

1.011 arc-sec/pixel and 8.3 arc-minutes.

The first equation (for arc-sec/pixel) is what isused to match the pixel size to the focal length.This expression tells us the relationship of sensi-tivity and resolution. Fainter deep sky objects needmore sensitivity. Planets, sun and moon need moreresolution. The higher the arc-sec/pixel number is,the more sky will be covered, the resolution will belower but the sensitivity will be increased. Thereare limits to this number. Operating at too large anarc-sec/pixel number and stars appear like blocksinstead of points of light and images are undersampled. Operating at too small of an arc-sec/pixelnumber there are too many pixels per star, resolu-tion is increased but sensitivity is lowered. Theseimages are over sampled. The general rule ofthumb to image deep sky objects is to use 1.5 to2.5 arc-sec/pixel. For planetary imaging, more res-olution is needed to see details on the planet and0.3 to 0.5 arc-sec/pixel gives good results. Theseare general rules of thumb and variations can stillgive adequate results.

The two factors to adjust the arc-sec/pixel num-ber is the focal length of the scope and the pixelsize.

Focal lengths can be easily adjusted. Barlowlenses increase the focal length by their multiply-ing number. 2x to 5x barlows are commerciallyavailable for most scopes.

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My 2x barlow with my 8 inch f/10 SCT resultsin a 2 * 2000mm = 4000mm focal length. My 2xbarlow and my 80mm f/5 refractor results in a 2 *400mm = 800mm focal length.

Focal reducers are lenses that reduce the focallength by the numbered ratio. An f/6.3 reducerreduces the focal length by a factor of 0.63 and af/3.3 reduces the focal length by a factor of 0.33.

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For example my f/6.3 reducer on my 8 inchSCT results in 0.63 * 2000 = 1260mm focal length.

f/3 to f/6 reducers are commercially availablefor many types of scopes. The amount of focallength change a barlow or reducer will achieve willdepend on the distance from the camera to thebarlow or reducer. Many barlows work at 2x wheninserted between the scopes diagonal mirror andthe eyepiece while giving 3x when insertedbetween the scope and the diagonal mirror. TheMeade f/3.3 focal reducer for SCT’s comes with dif-ferent spacers for a range of f/3 to f/5 reduction.The further the camera is from the reducer lensthe more reduction takes place. There are limits asto how much a given lens is designed to increase ordecrease the focal length. There is also a limit as tohow much focus travel your scope can accommo-date to work with these lenses. Check with thescope manufacturer to make sure these lenses willwork in your scope.

Pixel size can be adjusted if the camera allowsfor binning. Binning combines smaller pixels into abigger one. A camera with 9µ pixels binned 2 x 2will have 18µ pixels and when binned 3 x 3 willhave 27µ pixels. (Remember when calculating thefield of view to reduce the number of pixels in agiven direction by the number of pixels you arebinning.) Binning will not effect the field of view.The CCD active area will.

If your interest is only in one area such as deepsky OR planetary then select a camera with a pixelsize that complements that arc-sec/pixel with yourscope focal length (and barlow or reducer) and youare done. If your interest is in both then you needto compromise. You will need to add lenses and orpixel binning (depending on the camera you areconsidering) to get the range of sampling you need.For a range of 0.5 to 2.5 arc-sec/pixel you need afocal length change of 2.5/0.5 or 5. For 0.3 to 2.5you need a range of 8.3. How you get this willdepend on what barlows and reducers are availablethat will reach focus with your scope.

FFoorr eexxaammppllee

f/10 SCT has 2X and 3X barlows available. Theyalso have an adjustable f/3 to f/5 reducer available.This gives a range of 3/0.3 or 10, which is morethan enough.

With this telescope arrangement it would bebest to choose a pixel size to get 0.5 arc-sec/pixelfor average nights with a 2x barlow and go up to 0.3arc-sec/pix with the barlow at 3x on nights of goodseeing. For deep sky you need a focal reducer thatwill achieve 2.5 arc-sec/pixel on average nights and1.5 arc-sec/pixel on better nights. This range willalso help in framing the object to get the right fieldof view depending on the object size.

For an example with the 10 inch f/10 scope (Fl= 2500 mm) the following pixel size is determined.

For planetary viewing, 2X barlow and try to get0.5 arc-sec/pixel. Rearranging equation 1 and solv-ing for pixel size results in:

Pixel size = Arc-Sec/pixel * focal length / 206.2.65

With the 2X barlow the focal length becomes

Fl = 2 * 2500mm = 5000mm

The pixel size is:

Pixel size = 0.5 Arc-Sec/pixel * 5000mm focallength / 206.2.65 = 12.12µ.

To get 2.5 arc sec/pixel with the 12.12 µ pixelsfor deep sky imaging the focal reducer needed isfound by rearranging equation 1 to solve for focallength:

Focal length = pixel size * 206.265 / Arc-sec/pixel

Focal length = 12.12 * 206.265 / 2.5 = 1000mm

The focal reduction is found by dividing thedesired focal length by the focal length of the unal-tered scopes focal length or

Reduction = 1000mm/2500mm = 0.4

This is an f/4 reducer.

Meade sells an f/3 to f/5 reducer that wouldwork quite nice for this.

The desired pixel size calculated is a startingpoint in searching for a CCD camera. There areonly so many sizes available and most likely evenfewer sizes in a given price range. With this start-ing point look for a pixel size some where close towhat you calculated (+/- 30%). I know for a factthat the Stellacam with 8.4 by 9.8µ pixels workswill with 2000 mm and 2500mm focal length SCT’swith the 2X barlow and the f/3.3 reducer. Theselenses have a good operating range to adjust thefocal length to that desired. For the 10 inch f/10

H O R I Z O N 7

H O R I Z O N8

with the 2X Barlow, the sampling is 0.347 arc-sec/pixel and with the reducer operating at f/3 thesampling is 2.31 arc-sec/pixel. The 8 inch f/10 SCTis 0.433 arc-sec/pixel and 2.88 arc-sec/pixelrespectively. Both do a good job. A camera with27µ pixels wouldn’t be a good choice in the aboveexample.

Other considerationsThe field of view must also be considered in

imaging an object. If the CCD size is too small to fitthe object of interest then it will be of no interestat all. If you want to see an eclipse for example youwill need at least 0.5 degrees field of view to imagethe entire moon or sun. For most Messier objects a0.5 degree field of view will also work. Jupiter andSaturn are lost in this field of view. A field of viewof 2 to 10 minutes is better for planets as well asseeing detail on individual lunar craters andsunspots. The equation 2 used above for calculat-ing the field of view should also be used in deter-mining this at the desired focal length the camerawill be used at.

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10 inch f/10 SCT with the f/3 reducer, theStellacam 8.4µ pixels at 768 pixels across (hori-zontal) results in

arc-sec/pixel = 206.256 * 8.4 / (2500 * 0.3) = 2.31arc-sec/pixel

Horizontal field of view = 2.31 arc-sec/pixel * 768pixels = 0.49 degrees

Integration time is also important. If you wantto take deep sky images you will need a camerathat can integrate for 1 or more seconds even min-utes or hours depending on the cameras sensitivi-ty and scope aperture. A video camera with a stan-dard frame rates (and no integration) will not dodeep sky objects and will be only limited to plan-ets, moon and the sun with proper filters. Othercamera controls are helpful such as gain, shutterspeed and contrast. If in doubt see examples ofwhat a specific camera can do with scopes of dif-ferent aperture. CCD camera manufacturers oftenlist examples.

SummaryThe first consideration in choosing a CCD cam-

era for astro imaging is in choosing a pixel sizethat gives a good sampling for your scope. The gen-eral rule of thumb to image deep sky objects is touse 1.5 to 2.5 arc-sec/pixel. For planetary imaging,more resolution is needed to see details on theplanet and 0.3 to 0.5 arc-sec/pixel gives goodresults. This can be obtained with the addition ofbarlow and/or focal reducer lenses. Other factorsthen weigh in such as making sure the object fits inthe cameras field of view, integration time andother camera controls.

References(1) Holmes, Alan, Optimizing a CCD Imaging

System, Sky and Telescope webpage:http://www.skyandtelescope.com

(2) Apogee Instruments Inc. Telescope Opticsand Pixel Size: http://www.apogee-ccd.com

H O R I Z O N 9

BY PHIL HOYLE

For quite some time I’ve been looking for a lensor small telescope for piggyback photography witha longer focal length than my current 135mm tele-photo and 205mm zoom camera lenses. Fast, longfocal length professional camera lenses, althoughthe ideal choice, are way out of my price range.Most refractor telescopes small enough to ride pig-gyback on my 10-inch SCT have long focal ratiosand since I hate taking really long exposures, arenot a good choice for me. In comes the ApogeeWidestar 80.

Sky and Telescope and Astronomy magazinesboth run advertisements for Apogee Inc. In themonths before Christmas, their ads showed aphoto in a small box of the Widestar 90. In an evensmaller box, was a text only ad for the Widestar 80.The text says that it is the same scope as theWidestar 90 except that the objective is an 80mmf/5. Since my 205mm zoom camera lens is f/4.5,going to an f/5 shouldn’t really be that much of asacrifice to get nearly twice the focal length. Thatsmall text ad started looking really intriguing.What was even more intriguing was the introduc-tory price: $119.95! (Does not include shipping.)

When my wife and kids started asking me whatI wanted for Christmas, the Widestar 80 was nearthe top of my list. On Christmas morning, therewere two oddly large boxes under the tree with myname on them. One of the boxes was an officestyle chair for use at the computer, the other, quitesmaller than the box with the chair, was theWidestar 80. I decided to assemble the scope assoon as I opened the box.

When I opened the box, what I found greatlysurprised me, considering the advertised price ofthe scope. Most obvious was the aluminum tripod.Then of course was the German Equatorial mount.Last, but not least, was the telescope tube itself. Tothose familiar with the Celestron and Orion 80 mmf/5 scopes, the Widestar 80 is very similar. Thebiggest difference that I can see is the heavy plas-tic tube on the Widestar compared to the alu-minum tube on the Orion and Celestron models.

The telescope also came with a 25mm Plossl eye-piece an erect image diagonal and a ‘red dot’ andstyle finder.

As you all know, this has not been a great win-ter for observing. I did, however, manage to get outwith this new little scope a couple of times. Myimpressions are these:

I really like having a scope that I can pick up,mount and all, and just plop it down somewhereand start observing. (In contrast, my SCT takes aminimum of 15 minutes to set up.)

The optics seem quite sharp. This is somewhathard to test, since the eyepiece the scope comeswith delivers a whopping 16-power magnification.After trying out the scope with barlows and short-er focal length eyepieces, I quickly realized thatthe upper limit on magnification of this scopewould be limited. The problem isn’t so much thequality of the optics as much as the short focallength. While the short focal length is great forwide field views of deep space objects, it makes itvery difficult to get a good focus at high magnifica-tions. This is because the critical focus zone getsvery small with short focal length objectives andeyepieces. It is definitely not going to be a goodplanetary scope, but with the right eyepiece/barlowcombination, magnifications between 50 and 100 xshould be usable for most people. That being said,I wasn’t really interested in using the scope as aplanetary scope anyway.

The only negative I’ve found with the optics sofar is that the scope is probably not adequately baf-fled. While trying to point it at the Moon one night,there was a lot of light spilling to the eyepiece thatwas being reflected from the inside if the dewshield. There was so much light, in fact, that withthe red dot finder not yet aligned, it was difficult toaim it at the Moon, even at a magnification of only16 power.

The only other negative that I’ve come acrosswith the scope is that it did not come with direc-tions. That seemed really odd to me. Here was anear ideal scope for a beginner, someone thatwould really need the directions, and no direc-tions! I have since been in touch with Apogee Inc

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H O R I Z O N10

via E-mail. I have been told that directions shouldhave come with the scope and are on the way.(Apogee Inc. was very prompt with their reply.)

With the 16-power that results with the sup-plied eyepiece and the 80mm diameter objective,this little scope is essentially equivalent to one sideof Phil Creed’s 16x80 binoculars. For observing, Ithink I prefer the little scope though. The reasoncan be summed up with two words: the mount.The mount is quite simple to use if you are accus-tomed to a German Equatorial. It comes withmanual slow motion knobs and can also be pushedby hand easily. The mount is also ready to accept

a clock drive. I doubt that I would ever buy one forthis scope, mainly because my other scope alreadytracks, but if this were my first scope, it would bean accessory that I would probably want to pur-chase.

My over-all impression of this little scope is thatit is quite a bargain. Similar competitor’s scopesretail for more than twice as much when sold withan equivalent mount.

So how does the scope work for piggyback pho-tography? I’ll let you know after the weatherclears!

BY BILL CASTRO

This is an excellent introduction to videoastronomy. For most users it is the only referenceyou will need. The chapter titles pretty muchexplain what is covered. They are: Clear skiesthrough video eyes, How video cameras work,Selecting a video camera, Video signal processors,Choosing a VCR, Videocassettes cables and con-nectors, Combining video with computers, Hardcopy, The moon, The planets, Occultations andtransits, Eclipses, The deep sky, Meteors, Time-lapse animation, The sequential movie player,assembling a compact video camera, Resourcesand suggestions for further reading, Equipmentand supplies. The index and illustrations are excel-lent.

Many different CCD based cameras are dis-cussed such as camcorders, security cameras, webcams, Astrovid 2000 and STV. There is no mentionof the Astrovid Stellacam. This is most likely due tothe Stellacam being a very new camera. Althoughthere is mention of using barlows, there is no men-tion of using focal reducers. Field of views areimplied for different size CCD chip formats but theequations for calculating them for a specific optical

system are not given. The sampling suggestedusing Dawes limit and Nyquest Sampling Theoremseems a bit optimistic at 0.285 arc-sec/pixel for an8 inch f/10 SCT. But then again, just try it and it iseasy to back off the power to get a good picture onthe screen depending on the seeing conditions.The bottom line on this book is ….BUY IT!

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★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★

BY JOHN WEISS

On the evening of Wednesday November 13,1577 a young Danish aristocrat was out trying tocatch some fish for dinner from one of his well-stocked ponds when he noticed an unusuallybright star in the western sky. He quickly deter-mined that new star was not a planet. Saturn wasthe only planet visible at the time; he knew hisplanets and he knew that this was not Saturn.Furthermore, this star was a fuzzy blue-white ballwith a long reddish tail. It was a comet. He hadnever seen a comet before but the well-educatedaristocrat knew that this was a comet. In hisexcitement he forgot all about dinner.

That same autumn a German housewife fromthe small village of Leonberg led her five year oldson outside the village and up to the top of a hill toobserve the very same comet. It was a moment theyoung boy would never forget.

People in the late middle ages believed thatcomets were portents (usually doom and gloomportents) of the future. While most modern peoplereject such thinking as silly superstition, it istempting, at least in retrospect, to view the cometof 1577 as portending something positive. For itwas from this moment in history that the destiniesof the young Danish aristocrat, Tycho Brahe, andthe young boy, Johannes Kepler, appear to begin toconverge. Twenty years later it would result in oneof the greatest collaborations in the history of sci-ence.

In 1577 the independently wealthy Tycho, whodesigned and built his own precision crafted astro-nomical instruments, was already Europe’s mostfamous astronomer. Young Kepler, on the otherhand, who was already suffering from poor eye-sight, would never be much of an astronomicalobserver, but would grow up to become one of his-tories most important theorists.

Nothing illustrates Tycho’s skills better than hisobservations of the comet of 1577. Using his cus-tom built instruments that could make measure-ments down to a few minutes of a degree he dis-covered that the comet was moving 2-3 degrees

every day. Because he correctly assumed that thecomet was quite close to the earth he repeatedlytried to measure it’s parallax* and therefore, ofcourse, it’s distance. Unfortunately because it’shigh proper motion this proved to be more difficultthan he had anticipated.

His parallax measurements five years earlier ofthe nova of 1572 (we now know it was really a typeI supernova) were less ambiguous. The starshowed no parallax shift but also it didn’t exhibitany proper motion. Therefore, Tycho argued itmust be much farther out in space than the moon.

The Greek astronomer Hipparchus had suc-cessfully used parallax shift measure the distanceto the moon in the 3rd century B.C. Logically thenanything that didn’t show a parallax shift must beat a far out in the planetary or celestial sphere.Furthermore, Tycho argued that this showed thatthe Aristotelian teaching popular at the time wasdeeply flawed.

The Greek philosopher Aristotle (384-322B.C.) taught that the celestial sphere beyond theMoon, including the stars and planets were madeout of a special quintessential substance that wasintrinsically unchanging in it’s essential state.Tycho argued that the supernova of 1572, whichhad intrinsically brightened then dimmed, provedconclusively that Aristotle was mistaken.

H O R I Z O N 11

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However, Tycho was not satisfied simply argu-ing from negative results. Trying to measure “forreal” the parallax of something other than themoon became something of a lifelong obsession forhim. He tried on repeated occasions to measure heparallax of the planet Mars. He reasoned correctlythat the best time to attempt to measure its paral-lax was during opposition, which occurs aboutevery 25 months. He also knew that he would haveto be very accurate in his measurements to haveany chance of succeeding. He even tried to takeinto account the effects of atmospheric refraction.Unfortunately, we now know that the naked eyeinstruments that Tycho used, which could measure2-3 arc minutes, were simply not accurate enoughto detect the parallax shift of Mars. Parallax meas-urements would have to wait the invention of thetelescope.

Fortunately, Tycho’s failure to measure Mars’parallax was not all in vain. After Tycho’s death in1601 Johannes Kepler used Tycho’s careful andmeticulous records of Mars’ astronomical positionas a starting point to try to figure out the orbitalmechanics of the Solar System. Kepler discoveredafter months of tedious trial and error hand calcu-lations that, much to his surprise, the orbit Marswas a very subtle ellipse.

Ironically, no other set of measurements, madeby any other astronomer living up to that time inhistory, would have been accurate enough to revealthat Mars’ orbit was an ellipse. Only the carefuland meticulous measurements made by Tycho,using the gold and brass instruments that he haddesigned and built himself, were accurate enoughto yield the elliptical orbits that Kepler’s calcula-tions teased from the data.

It was something that neither Tycho, norKepler, nor anyone else had been looking for. Yetit was this seemingly minor discovery that trans-formed the Copernican theory into a theory thatwas not only simple and elegant, but one that wascapable of making highly accurate predictions.

It was an accidental but fortunate discoverythat Kepler stumbled onto. We have a special wordfor that kind of thing. It’s what we call Serendipity.

What is parallax? Try this little experiment.Shut one eye and extend your finger so that is atarms length. Position your finger so that it blocksout a picture on the far wall in your living room.Now repeatedly open one eye and close the other.You will notice that because of the difference ofperspective of each of your eyes your fingerappears to jump back and forth in relationship tothe background (the picture and the wall).Astronomers see this same kind apparent shift fornearby planets and stars against more distant“background stars” due to the earths movement onit’s axis or in it’s orbit. This movement changes theperspective of an earth bound observer. By meas-uring how much the foreground planets or starsappear to shift the astronomer can mathematicallycalculate its distance.

SourcesFerguson, Kitty. Tycho and Kepler: The

Unlikely Partnership That Forever Changed OurUnderstanding of the Heavens, Walker andCompany, New York, 2002.

Hirshfeld, Alan W. Parallax: The Race toMeasure the Cosmos, Henry Holt and Company,New York, 2001.

H O R I Z O N12

BY DAVE GILL

If weather permits, we have will see a fine lunareclipse on the evening of Thursday, May 15/16. Ithought I’d take this opportunity to write aboutwhat goes on during a lunar eclipse, how to inter-pret the standard presentation of eclipse circum-stances, and little about observing and photo-graphing it.

I’ve included the figure from pg. 149 of theObservers Handbook 2003. This is prepared byFred Espenak, and is found on his web page at:http://sunearth.gsfc.nasa.gov/eclipse/LEplot/LEplot2001/LE2003May16T.gif

Of course, what goes on during a lunar eclipseis that the moon wanders through the Earth’s shad-ow in space and is briefly darkened. For this tohappen, the moon must be exactly opposite thesun – with the Earth in between. But why doesn’tthis happen every month? Isn’t that what fullmoon is? Well, sort of.

If the moon orbited the Earth in the exact sameplane as we orbit the sun, then we would haveeclipses every month. But, the moon’s orbit is tilt-ed or inclined to our orbit about the sun (called theecliptic) by about 5 degrees. So most of the timewhen the moon is opposite the sun it is above orbelow the conical finger of shadow reaching outfrom the Earth. The line where the two planescross is called the line of nodes. This line slowlyregresses along the ecliptic over a period of 18.61years. Usually during two months during the year,we have “eclipse seasons” when the moon is closeenough to the nodes to eclipse or be eclipsed.

When the moon passes through the Earth’sshadow, it experiences two types of shadow. Thefirst is a shallow shadow, called the penumbra.The penumbra results from part, but not all of the

sun’s light being blocked. Penumbral eclipses arefar from obvious. The deeper the moon enters thepenumbra, the darker it becomes.

The full shadow of Earth is the umbra. Whenthe moon enters the umbra, you begin to noticedefinite shadow line on the face of the moon. Asthe moon penetrates the umbra more deeply, theshadow marches across the face. As the moon getscloser to being totally eclipsed, we notice that thedark shadow region is now revealing details. Howcan this be? In the shadow of Earth, the moonshould be dark. It would be, except that the Earthhas an atmosphere. That thin layer of air acts likea thin, annular lens. A small amount of sunlightgets refracted and scattered by the atmosphere.The result is a dim illumination of the moon – kindof like a night light.

One of the big question marks about anyeclipse is how dark the umbra will be. The dark-ness of the moon is a function of how deeply themoon penetrated the umbra (easy to predict) andhow dusty Earth’s atmosphere is (much harder topredict). If the air is filled with aerosol particles,like from a volcanic eruption, much of the lightthat would normally be refracted to redden themoon ends up scattered by the dust. The Dajonscale given below is how the darkness of eclipsesare rated.

L = 0 Very dark eclipse.Moon almost invisible, especially at mid-totality.

L = 1 Dark Eclipse, gray or brownish in col-oration.

Details distinguishable only with difficulty.

L = 2 Deep red or rust-colored eclipse.

Very dark central shadow, while outer edge ofumbra is relatively bright.

L = 3 Brick-red eclipse.

Umbral shadow usually has a bright or yellow rim.

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L = 4 Very bright copper-red or orangeeclipse.

Umbral shadow has a bluish, very brightrim.

Reading the DiagramThe eclipse diagram gives times in

Universal time. Subtract 4 hours to getEastern Daylight time.

“Greatest Eclipse” is the time of maxi-mum immersion into the shadow. It is givenas 3:40 UT or 11:40pm EDT.

Eclipse timings are given as “contacts”.P stands for penumbral; U for Umbral.

P1 is the first contact of the moon withthe Earth’s penumbra. It will be a whilebefore you notice any darkening. But beforethe first umbral contact, you should noticethe moon looking somewhat darker.

U1 is the first umbral contact – when thefirst edge of the moon touches the umbra. Atthis point, you begin to see the umbra cross-ing the face. You can often find tables listingwhen various craters will pass into the shad-ow.

U2 marks the point of full immersion.The moon is fully in the umbra. U3 marksthe point where the moon begins to emergefrom the umbra, Between U2 and U3 themoon is totally eclipsed, in this case fornearly 53 minutes. During that time you cannote changes in the darkness and color ofthe eclipse.

U4 marks the final umbral contact, whenthe moon fully leaves the umbra. A finalpenumbral passage ends the eclipse at P4.

ObservingYou don’t need any equipment if you don’t have

any. Binoculars or a telescope allow you to betterfollow the progress of the shadow. Photography iswell explained in the references below.

http://www.mreclipse.com/LEgallery/LEphoto.html

http://www.u-net.com/ph/mas/observe/lunar-p/lunar-p.htm

http://skyandtelescope.com/observing/objects/eclipses/article_89_1.asp

H O R I Z O N14

BY DAVE ROSS

The loss of the Columbia space shuttle made usaware of the seven extraordinary people whoserved as her last crew on that fateful mission.Mixed with the many tears that were shed in thewake of the disaster were perhaps a few for ateenage boy who died nearly sixty years ago.Israeli astronaut Ilan Ramon carried into orbit apencil drawing by Petr Ginz called MoonLandscape. It was part of the collections of the YadVashem museum in Israel, dedicated to remember-ing martyrs and heroes of the Holocaust. Ginz wasfourteen years old and imprisoned in theTheresienstadt ghetto in 1942 when he drew hisvision of what the earth might look like from thesurface of the moon. He was killed at Auschwitztwo years later, but surviving family and friendssaved his many drawings, poems and stories whichare now preserved at the Yad Vashem museum.Officials there selected the drawing believing itstheme would make a personal connection with theastronaut whose mother was herself a Holocaustsurvivor.

The drawing is striking in its own right, butnow more so as we know part of its story. When Ilook at it I wonder what might have inspired Petr

Ginz to draw it as he did. In happier days as achild did he ever look through a telescope at themoon’s stark landscape? Did he dream often ofthat ‘magnificent desolation’ that greeted the firstastronauts to walk its forbidding surface? Had heread about the moon in popular astronomy bookswith depictions inspired by the works of J. H.Nasmyth and James Carpenter? The sharp thornytops of the mountain he drew remind me of someof the jagged and craggy features of lunar land-scapes inspired by their 1874 book on the moon.(See: Epic Moon by Sheehan and Dobbins, ch. 14.)Why are there three peaks to each mountain? Orare they extinct volcanoes, as Nasmyth andCarpenter believed? Are they intended to suggestwhat a hostile place the moon must be, or do theyreach longingly for an earth made heavenly in ayoung man’s imagination? I wonder about thedreams of those brave seven that helped carrythem into space, and of other young people whowill still be inspired, despite or because of theirsacrifice, to follow them.

Perhaps Col. Ramon’s comments say it best. Inan interview during his training in Huston he said,“I feel that my journey fulfills the dream of PetrGinz 58 years on. A dream that is ultimate proofof the greatness of the soul of a boy imprisonedwithin the ghetto walls, the walls of which couldnot conquer his spirit. Ginz’s drawings… are a tes-timony to the triumph of the spirit.” Triumph ofthe spirit. So be it.

H O R I Z O N 15

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Petr Ginz (1928-1944)

BY RALPH GESCHWIND

Temperatures should be getting warmer at night as the spring constellations are coming up from theeast. Here are some variables that I observe with my 10-inch f/5.6 reflector.

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1552+29 Z CrB Mira 10.0-14.1 259d

1544+28a R CrB Irr 5.9-15.0 __

R CrB-type stars are very unusual variable stars. They stay at maximum for years and suddenly startto descend to minimum magnitude. In February R CrB started to fade, but suddenly stopped after itreached 12.7-13.0 magnitude and it looks like it is slowly getting brighter. I have been observing this starfor many years. The AAVSO finder chart for R Coronae Borealis is on the following page.

1544+28b TT CrB SrB 10.9-12.1v 60dthis is a semi regular star (located near R CrB)

1517+31 S CrB Mira 7.0-12.8 361d

1545+36 X CrB Mira .0-13.6 238d

1546+39 V CrB Mira 7.8-11.3 358d

1611+38 W CrB Mira 8.3-13.0 238d

1555+26 T CrB Irr 2.0-10.6 —

T CrB is called a recurrent variable star because it acts like a nova star and its take a very long timeto erupt. It erupted in 1946 and won’t again till 2026 - 80 years. Maybe I will get to see it.

1418+54 S Boo Mira 8.5-13.4 271d

1425+39 V Boo Mira 7.5-10.7 260d

1433+27 R Boo Mira 7.1-12.3 223d

1449+18 U Boo Mira 10.0-12.2 199d

If you are interested in starting to observe variable stars, contact me, Bill Castro or Dave Gill

H O R I Z O N16

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H O R I Z O N 17

April 20034th: Planetarium show and Public Viewing Night

7:30 @ TWC – Clear or Cloudy!

25th: WCAC Meeting - 7:30pm @ TWC IB Program: NASA Speaker Scott Benson, “Ion Propulsion and Future Outer PlanetExploration Missions” Refreshments: Gene Rickenbrode

27th: Planetarium show - 2pm @ TWC AEB

May 20032nd: Planetarium show and Public Viewing Night

8:30 @ TWC - Clear or Cloudy!

4th: TWC Open House, 1-4, (set up at 11) @ TWC

14th: Planning Committee – 7:00pm @ John’s house

25th: Planetarium show - 2pm @ TWC AEB

May 200330th: WCAC Meeting - 7:30pm @ TWC IB

Program: Telescope Thermal Improvements By Bryan Greer Refreshments: Ralph Geschwind

June 20036th: Planetarium show and Public Viewing Night

7:30 @ TWC – Clear or Cloudy!

22nd: Planetarium show - 2pm @ TWC AEB

27th: WCAC Meeting - 7:30pm @ TWC IB Program: Show and Tell Gadgets & Books Refreshments: TBD

July 20034th: CANCELED- Public Viewing Night

25th: WCAC Meeting - 7:30pm @ TWC IB Program: TBD Refreshments: TBD

TThhee EEvveenntt HHoorriizzoonn

The Wilderness Center Astronomy ClubP.O. Box 202Wilmot, Ohio 44689