the newsletter of th e QUEEN ELIZABET H PLANETARIUM DEC. 80/JAN . 81 and the EDMONTON CENTRE, RASC 50*

the rings of Saturn from Voyager 1 Will giant earthquakes occu r in 1982 ? Do sunspot s affect lif e on eart h ? What were the Martian canal s ? Did ancient civilization s possess advanced astronomical knowledge ? Are UFO' s rea l ?

TO FIN D OUT, SEE...,

narrated by Leonar d Nimoy

NOW PLAYIN G AT A PLANETARIU M NEA R YO U

Queen Elizabet h Planetarium SHOWTIMES : Tuesda y - Friday at 8 pm Saturday, Sunday an d Holiday s at 3 pm and 8 pm (no show s Christmas and Ne w Year's Day) Vol. 26 No . 1 di DEC. 80/JAN . 81

- A Deep-Sk y Portfoli o JOH N LEADE R 8 At my observatory near Medicine Hat it is possible to photograph 12 months of the year, even in high summer, due to our southern latitude. How Radi o Telescope s Wor k DAV E BEALE .... 1 4 Radio astronomy is basically similar to optical astronomy except that the Editor received radiation is at a much lower frequency. Alan Dyer A Continent-Wid e Radi o Telescop e 1 8 Assistant Editor If approved, the VLBA would create a significant advance in our knowledge of Stewart Krysk o the universe. Contributing Editors Ted Cadlen John Hault Dave Holmgre n Mark Leender s The Fron t Pag e Editor' s Message 2 Andrew Lowe Rod McConnel l Astronomy Basic s Th e Messier Catalogue 4 Anthony Whyte General Meetin g Notice 5 Typesetting Discoveries Hundred s an d Hundreds of Ring s 6 Loma Mllllga n RASC New s 2 1 Graphic Arts Dave Belche r At The Planetariu m 2 3 Rick Corrigan Look Bac k Tim e 5 0 and 100 Years Ago 2 4 Printed by What's U p ? Let' s See Orion Again 2 5

The City Of EDMONTON Parks and Recreation COVER: O n Nov . 12, Voyage r 1 passe d withi n 125,000k m o f Saturn , returnin g spectacular close-up photos of the planet, Its rings, and its moons. In this photo, taken on Oct. 30 from a distance of 16 million km, we can see the full extent of the rings, from the outer edge of the bright A-rlng, past Encke's Division, the remaining major portion of the A-rlng, Casslnl's Division, the B-rlng, and the dark Inner C-ring. The shadow of the rings on the planet ca n also be seen. See page 6 for mor e details.

Deadline lo r Feb./Mar . issue : Monday , Januar y 1 2

STARDUST, the newsletter of the Queen Elizabeth Planetarium and the Edmonton Centre, RASC, is published bi-monthly and is available free to all members of the Royal Astronomical Society of Canada, Edmonton Centre as a benefit of membership. Single copies are available at the Planetarium Bookstore for 50* . STARDUST i s also available by subscription fo r $4.50 per year for 6 issues ($9.00 for two years for 12 issues). Please make all cheques or money orders payable to: The Queen Elizabeth Planetarium. Write to: The Editor, STARDUST; c/o Queen Elizabeth Planetarium; CN Tower 10th Floor, 10004 - 104 Avenue; Edmonton, Alberta, T5J OK1. Unsolicited articles or photographs pertaining to any aspect of astronomy are welcome. EDITOR'S MESSAGE I'd like to take the opportunity t o wish all our readers, wherever they ma y be , a very happ y holida y season , an d a prosperous Ne w Year. I hope that one of your resolutions for 198 1 is to write an article or two for Stardust. Item s of any length are welcome, whether they be short observing reports or feature length articles. Astro-photograph y is particularl y welcome , preferabl y i n the for m o f btack-and-whit e prints. All I ask is that to avoid disappointment pleate hand in material before th e deadline. I n 198 1 i t woul d b e so nic e i f I didn't hav e t o the continually pro d people into submitting their promised contribution s to Stardust o n time. If you ar e putting together a major article (i.e. longer than on e front Stardust page) , please let me know about i t beforehand so I can fit it into a n upcomin g issu e a s soon a s possible . I generally hav e th e overall contents of issues planned 3 or 4 months in advance, and the page more lea d time I have for big articles, the better I like it. The next issu e (Feb./Mar.) will feature an item by Paul Deans on life at the Jet Propulsion La b during the Voyager Saturn flyby, and an article b y Kare n Finstad on observin g a t the University of Toronto's observing sit e in the southern hemisphere . The Apr./May issu e will again centre around STARNIGHT, tentatively scheduled fo r May 8/9. Throughout this issue , on th e other hand , you'l l fin d constan t reminders that it's time once again to renew your RASC membership. In fact, i f you haven' t renewed to date , then yo u ar e receiving this issue for free , as an enticement t o join again . But the Centre can't afford to kee p sending ou t free Stardusts to last year's members, so those who are not on the "paid - up members" list by Dec. 31 will no longer receiv e Stardust\d as I know you are by this prospect, may I kindly sugges t tha t this fate can b e avoided b y payin g you r dues. Give the Centre a Christmas present! If for some strange reason you do not intend to rejoin the Centre this year , bu t stil l wis h t o receiv e Stardust, yo u ca n d o s o b y subscribing fo r $4.50/year . Make all Stardust subscriptio n cheque s payable to "The Quee n Elizabeth Planetarium." Cheque s for RAS C membership renewal s (which include s a year's worth o f Stardusts} should b e payabl e t o "Th e Edmonto n Centre , R.A.S.C. " Bot h payments can be mailed to the Q.E.P. at the usual address on the back cover. Thank you for your continuin g support. —Alan Dye r Hours 8:30a m • 4:00pm; 6:30pm - 9:00pm Tues. - Fri . 1:30pm - 4:00pm; 6:30pm • 9:00pm Sat. & Sun. Coronation Park , Edmonton PH 455-011 9 Looking fo r a n astronomica l Christma s present ? Th e Bookstore has a wide variety of items suitable for gifts - everything fro m stockin g stutter s an d noveltie s t o complete telescopes. Drop by and se e us!

E D

Introducing the MEAD E SYSTEM 2000: a new 8-inch f/10 Schmidt-Cassegrain telescope . MeadeS- Schmidt-Cassegrain 31250.0 0 Meade 4= Schmidt-Cassegrain: with fork mount $8650 0 wtth German equatorial mount $7700 0 Equatorial wedg e tor 4= or 8= $6 5 00 Reid Tripod $1900 0 4= f/2.64 Schmidt Camera $670.0 0 Looking fora CELESTRON, the most Doputartetescope in the world? Loo k no further CetestronS ..S1450.00 C8 Package , wtth wedge and tripod. ..$1575.00 Cetestron 5 ..$116000 C6 Package, wtth wedge and tripod. ..$127500 C90 Telescope ....$750.00 C90 Spotting Scope ....$53000 C90 Tetephoto Len s ....$40000 o/lionomy bo/ic / the me//ie r catalogu e

There ar e thousand s o f sta r clusters , In fact , Messie r ofte n use d achromati c nebulae, and galaxies within reac h of amateur refractors of this size. telescopes. Ho w ca n the novic e observe r sort Another question tha t usually comes up is out the bes t and the brightest fro m this wealth how many objects are actually on Messier's list? of deep-sk y wonders ? It' s simpl e — someone His Catalogue was published in 3 installments. has already don e th e sorting for you : Charle s The first, published in 1774, listed 45objects, 40 Messier. of which wereoriginal Messierdiscoveries. M40 He was a French astronomer wh o live d i n is actually only two stars. Messier knew this but the lat e 1700's , when observational astronomy listed i t anyway since previou s observers had was becoming a fine and noble art. Messier was reported i t as being nebulous. Even though they interested i n discoverin g comets , a tas k a t were alread y well-know n objects , M42 , M43 , which he was very successful. During his career M44, an d M4 5 were als o added , likel y just t o he discovered 21 comets. But h e is best known "round off" the list at 45. today for hi s list of other discoveries, of those pesky little nebulous patche s he kept bumpin g into a s he scanned the sky for comets. Lest he and othe r observer s mistak e thes e "fals e comets" for the real thing, Messie r decided to compile a catalogu e o f comet-lik e objects . Messier's catalogu e remain s toda y a s a compilation o f mos t o f th e fines t clusters , nebulae, and galaxies in the sky, and is the best starting poin t for amateur astronomers getting into deep-sky observing . Messier himsel f di d no t discove r al l th e objects o n hi s list . Som e wer e know n abou t long befor e Monsieu r Messie r cam e along , objects lik e th e Pleiade s (M45) , the Beehiv e cluster (M44) , an d the Orion Nebula (M42) . I n his late r years , Messier was assisted by Pierr e Mechain, wh o checke d ou t Messier' s findings and i n th e proces s discovere d a numbe r o f deep-sky object s o f his own. All o f Messier' s object s ca n b e see n in a telescope as small as a 60mm refractor, though The firs t supplemen t t o th e origina l the fainte r one s woul d requir e som e hunting . catalogue cam e ou t i n 1780 , and include d 2 3 According t o historia n Owe n Gingerich , new object s bringin g th e tall y u p t o 68 . A Messier use d a t on e tim e o r anothe r ove r a second supplement , publishe d i n 1781 , added dozen telescopes. The largest, and his favorite, 35 mor e objects , 2 7 of whic h wer e found b y was a Gregoria n reflecto r o f 7 1/2-inche s Mechain. This brings the Messier Catalogue to aperture. Keep in mind, however, that reflectors the classi c 10 3 objects. in thos e days , wit h thei r speculu m meta l Messier planne d a thir d revisio n t o hi s mirrors, wer e fa r les s efficien t tha n today' s catalogue, bu t th e Frenc h revolutio n telescopes. Th e 7 1/2-inch wa s equivalen t i n intervened, and the new supplement was never light-gathering power to a 3 1/2-inch refractor. published. I t wa s t o contai n som e mor e o f Mechain's discoveries, objects now referred to respectively.) as M10 4 - M109 . Toda y w e ofte n hea r o f a n Why ar e Messier' s object s scattere d a t M110 a s well . Thi s i s NG C 205 , on e o f th e random around the sky? The Catalogue was not companion galaxie s t o M31 , th e Andromed a the resul t o f a systematic searc h for nebulou s Galaxy. The basis for this modern addition is an objects - - tha t wa s lef t t o th e Herschel s wh o 1807 memoi r o f Messie r whic h contain s a n were active as Messie r was ending hi s career. engraving showin g M31 , an d bot h o f it s Messier, on the other hand, recorded objects as companions, M3 2 an d NG C 205 . Neithe r he came across them while persuing his favorite Messier o r Mechai n referre d t o NG C 20 5 as pasttime, searching for comets. A reordering of "M110", though i t appears as if Messier was its all the objects by right ascension wa s planne d discoverer. He simply neve r published the fact. as part of the third supplement. Messier' s failing So today, after some modern tinkering, we health i n th e earl y 1800' s prevente d hi m fro m have a Messier Catalogue with 110objects, but completing this work. He died in 1817, at age 87. with at least two objects (M91 and M102) whose When was he born? —In 1730, exactly 250 years identity i s stil l debated . ( A good cas e can b e ago this year. made fo r identifyin g thes e tw o troublesom e — Alan Dyer objects a s NG C 454 8 an d NG C 586 6

NOTICE o f GENERA L MEETING S

MONDAY, DECEMBER 8

MR. ALAN DYER MR. FRANKLYN LOEHDE Edmonton Centre, RASC Edmonton Centre, RASC "Collecting Storiigh* ft? "The Universal Key " to Deep-Sky - Astronomers lear n abou t th e univers e b y The hobt»- analyzing Ight and other forms of radiation that reaches us here on earth from distant space. One of the mai n techniques used to to disperse the .cessortes, •ght Into a spectrum. In one of Ms rare speaking 6^- ails fascinatin g engagements befor e th e Edmonto n Centre , << a s a n excellen t Franktyn Loehd e wil l tel l u s abou t wha t suc h |ust startfn g ou t I n spectra can tell us about the universe and al Its myriad contents . I t promises to be an excellent and enlghtenlng presentation.

Both meeting s at: 8:00 PM : MUSI C ROOM , EDMONTO N PUBLI C LIBRAR Y Guests an d member s o f th e publi c ar e invite d di/coucfic/ Q/tronomy new / updat e

HUNDREDS AN D HUNDRED S OF RINGS ! "The bizarre has become the rule." Travelling outwar d fro m Saturn , the next That wa s th e opinio n o f E d Stone , Chief stop i s Mimas . I t i s uniforml y saturate d wit h project scientist for the Voyager mission on the craters, wit h on e hug e impac t crate r an d a occasion o f Voyage r 1' s closes t approac h t o central pea k dominating it s surface. The event Saturn. O n Nov. 1 2 it flew to within 125,000km that create d thi s structur e mus t hav e bee n of Saturn' s cloudtops , returnin g photograph s powerful enoug h t o almos t shatte r th e littl e that are the most beautiful results yet from over moon. Mimas's sister moon, Enceladus , is very two decade s of space exploration. different, wit h a smoot h surfac e devoi d o f Discoveries poure d i n wit h ever y ne w prominent features . Wh y th e difference ? N o photo and data bit : one know s yet . Tethy s again show s lot s o f Voyager confirmed the existence of 3 new craters, plu s on e hug e canyo n scarrin g it s moons discovered from earth in 1980. They are surface. Dion e an d Rhe a ar e als o siste r now calle d S10 , S1 1 and S12 . S1 2 shares th e satellites, bot h exhibitin g heavil y cratere d same orbit with Dione . S10 and S11 are known surfaces. Her e w e fin d brigh t highlan d area s as the "co-orbital " satellites, as they, too, share and darke r mar e area s as on ou r ow n moon , nearly identica l orbits . Thei r distanc e fro m plus brigh t ray s an d wisp s o f ic y materia l Saturn differs by only 5 0 km, meaning that one spewed acros s th e surface . Thes e ar e world s co-orbital moo n travel s slightly faster than the that als o resembl e Ganymede' s patch y other. When they come together (as they will in appearance i n many respects. January, 1982) , it isthoughtthey avoidcollision Then we come to Titan, largest moon in the by switchin g orbits . Fro m Voyage r photos , solar system . Voyage r wa s confronte d wit h these tw o strang e satellite s ar e clearl y essentially anothe r Venu s — th e Titania n fragments o f som e large r object . Voyage r surface wa s nowher e t o b e seen , burie d photographed th e shado w o f a previousl y beneath a thick an d featureless atmosphere of unknown rin g crossing the surfaceof one of the reddish methane and nitrogen clouds. Voyager co-orbitals. photographed layerin g o f clou d i n th e uppe r Voyager the n discovere d 3 ne w moons , atmosphere o f Titan . Th e da y afte r th e Tita n ones previously unsuspected, even from recent flyby, projec t scientist s speculate d abou t earth-bound research . Thi s bring s th e tota l oceans o f liqui d nitroge n beneat h th e clouds. Saturnian moo n populatio n u p to 15 . S13 and Titan's atmospheric pressure , long a mystery, is S14 orbit on either side of the newly-discovered now know n t o b e denser than the pressure of thin F-ring, itsel f situated above the bright outer earth's atmosphere. Thi s is a world we need to A-ring. Satellite s 1 3 an d 1 4 ar e know n a s know muc h mor e about. "shepherd" satellites , sinc e throug h thei r Astronomers kne w ther e wa s something gravitational tug, they keep the ring particles "in unusual about lapetus long before Voyager was the pack " orbitin g i n th e F-ring . S15 , a tiny ever launched . Th e spac e prob e confirme d moon 80 0 km above the A-ring an d only about suspicions tha t on e hemispher e o f lapetu s i s 100 km in diameter, performs the samefunction substantially darke r tha n th e other , an d for the A-ring particles , keepin g this larg e ring evidence seem s t o poin t t o interna l geologi c intact, o r a t leas t definin g it s shar p oute r forces a s th e reason , rathe r tha n externa l boundary. bombardment. A close-up o f Casslnl's Division, bounded b y the two dark gaps but containing a t least 6 distinct ringlets.

But when it came to Saturn' s rings, no one The mysteriou s black spoke s i n the ring s expected to see what Voyager revealed —the A, that radiat e outward from Satur n and mov e as B an d C-ring s al l resolve d int o hundred s o f the ring s revolved , turne d ou t t o loo k brigh t rings each . Cassini' s division, the broa d black when seen from the otherside of Saturn looking gap separating th e A and B-ring, was found to back towar d th e su n an d earth . Thi s contain not empty space, but at least 6 smaller immediately suggested that the spoke patterns rings, with one of them eccentric. Asymmetrical were create d b y dust-lik e particle s i n o r jus t rings shouldn' t exis t aroun d Saturn , but the y above the rings . do. Th e oute r F-rin g i s twisted and braided i n We learne d mor e abou t Satur n i n places, an d ha s a clump y appearance . November than w e have been able to discover Previously th e gravitationa l influenc e o f th e about th e plane t sinc e Galileo first trained hi s inner satellites was thought t o b e the cause of telescope o n i t 370 years ago. Muc h ha s been the few rin g divisions see n from earth and by learned even in the first few days after the hectic Pioneer 11 . But now, with rings where divisions close encounter , bu t a s man y discoverie s as should be, and a wealth of divisions where there these stil l remai n stored i n th e ream s of data , should b e a soli d swar m o f particles , th e ol d waiting to b e analyzed. I t will take years. satellite "resonance " theor y need s reworking , Meanwhile, Voyage r 2 i s closing in , fo r a to say the least. One scientist felt that a whole rendezvous with Saturn in August, 1981, the last new science of orbital mechanic s may have to space prob e unti l 1986 . be develope d jus t t o explai n th e Saturnia n Watch for mor e on the Voyager 1 - Satur n system. encounter i n the nex t issue of Stardust. n Deep-Sky Portfolio

Taking advantage o f the clear skies of south-eastern fllberta, a small but active astronomy clu b has been formed in Medicine Hat. One of it s organizers i s an avid astro-photographer. His photographs o f deep-sky objects have recently won several awards in an international competition.

text an d photographs by JOHN L€flD€R The WHIRLPOOL GALAX Y (M51 ) In Canes Venatlch __ 2 5 minutes a t f/5, Celestro n 8 103ae film, negativ e prin t The southeaster n Albert a dr y land s ar e task tha t i s fa r easie r sai d tha n done . Th e • considere d b y man y t o b e an inhospitable telescope i s drive n b y a cloc k driv e whil e an area. Prickl y pea r cactu s aboun d an d auxiliary "guide " telescope , workin g a t hig h rattlesnakes ar e no t uncommon , bu t fo r th e magnification, i s used to monitor the position of study o f som e o f th e dimme r astronomica l a brigh t sta r nea r th e objec t bein g objects, thi s are a offer s man y definit e photographed. Durin g th e exposure, I observe advantages. Du e t o th e sparcenes s o f th e this guide star, making corrections for any shift population i n thi s par t o f th e province , dar k in th e positio n o f th e telescop e befor e errors skies so necessary for deep-sky observing and crop up on the film. photography ar e easily found. I t is possible t o The accuracy wit h whic h th e telescope is photograph durin g twelve months of the year, polar aligned i s very critical. Any misalignment even i n hig h summe r du e t o ou r "southern " will caus e excessiv e imag e drif t an d wil l latitude. necessitate guidin g correction s whic h wil l Deep-sky photograph y refer s t o lon g inevitably result in those "football" star images. exposure photograph y (u p t o on e hou r Black and whitefilmsthatare usually found duration) of faint astronomical objects such as: at the corner drug store such as ASA 400 Tri-X supernova remnants , hydroge n emissio n are mad e for th e recording o f reflected light at nebulae, spiral galaxies, globular an d open star the bottom of earth's atmosphere, and are quite clusters. Th e advantag e o f deep-sk y insufficient for deep-sky photography. Ther e is photography i s that the film used has the ability an answe r though . Koda k ha s bee n to build up the image collected by the telescope manufacturing specia l blac k an d whit e over a period of time. Thus a time exposure can emulsions for astronomy for many years. These record muc h mor e detai l o f a dim object than are calle d "spectroscopic " films . Thes e films the fully dark-adapte d ey e can perceive. are perhap s thre e times faster tha n Tri- X and The observator y wher e I carr y ou t m y will efficientl y collec t ligh t ove r a n hou r photography i s located 20km south of Medicine exposure. On the other hand, Tri-X after about Hat, at Woolchester, Alberta. The Woolchester ten minutes reaches almost zero sensitivity. To Observatory, a small home-built 2-meter dome, my knowledge , thes e spectroscopi c film s houses an equatorially mounte d 8-inch (20cm) designated 103a-E, 103a-F, and 103a-Oare not Celestron telescope . available i n Canada , bu t ca n b e purchase d My Celestro n 8 is equipped t o operat e a t through th e mai l fro m America n suppliers . two foca l ratio s fo r photography , either a t f/5 Consult th e majo r astronom y magazine s fo r {giving a foca l lengt h o f 1000mm ) o r a t f/1 0 ads for firms that carry these films i n stock. (2000mm). The shorter focal length produces a I have found tha t developing m y own film smaller but brighter imag e on thefilm, reducing helps me to enjoy my hobby to the fullest. There exposure time , whil e th e longe r foca l lengt h is a real excitement when the negatives from the produces a mor e magnifie d imag e whic h previous night' s photograph y sessio n ar e contains mor e detail . developed, giving m e the first look at the spiral To obtain astro-photos that are pleasing to arms of an elusive galaxy. look at , sta r image s mus t b e sharp, i.e . the y — Joh n Leader must loo k lik e dots , no t footballs, worms, etc. This mean s that the object has to be accurately tracked acros s the sky during the exposure, a 10 - It is possible t o photograp h during 1 2 months of the year. I Rattlesnakes ar e not uncommon, b for astronomy, this area offers son definite advantages. t There i s a real excitement uuhen the negatives from the previous night's sessio n ore developed. Don't le t all th e fancy electronic s frighten you . Radi o astronom y i s actually very similar t o optical astronomy I n many respect s

The objec t o f professiona l astronom y i s t o 300 metres, while for F M radio frequencies, the • gathe r informatio n abou t th e universe , A = abou t 3 metres . Re d light , o n th e othe r information carrie d vi a electromagneti c hand, a t a frequenc y o f 0. 3 thousand millio n radiation. Thi s radiation could be in the form of million H z has a A of one mi I Month of a meter. In radio waves , ligh t waves , X-rays , o r eve n radio, the polarity o f the radiation is defined as gamma rays . W e ar e al l familia r wit h ho w the direction of the electric field lines--the field astronomers receiv e and manipulat e ordinary shown i n FIG . 1 i s verticall y polarize d fo r light, but i n radio astronomy , how on earth do example. astronomers extrac t informatio n abou t th e Radio astronomy, then, is basically similar universe from what sounds like only a stream of to optica l astronom y except that th e received radio static ? radiation i s at a much lowe r frequency. THE ELECTROMAGNETIC SPECTRU M THE RADI O TELESCOPE ANTENN A Electromagnetic radiatio n can be thought Optical telescopes collect electromagnetic of a s particles (calle d photons) o r a s waves. If energy, magnif y i t an d for m a n image . Radi o the wav e theor y i s used , whic h i s mor e telescopes don't form images normally, for very ^appropriate at radio frequencies, then the name good reasons . For one thing, to form an image, says i t all . Th e electromagneti c radiatio n reasonable resolutio n i s required. This in turn consists of an electric field and a magnetic field requires a large aperture compare d to the size at right angles, illustrated i n FIG. 1. Referring to of th e wavelength being received . To see how "FIG. 2 , w e se e a sine wave, whic h al l large, we can figure out how many wavelengths electromagnetic radiatio n can be measured as. there ar e i n th e diamete r o f a 20c m (8" ) On th e vertica l axi s o f thi s grap h th e telescope: "amplitude" or strength o f the signal is plotted, The wavelength of green light , the color i n the and o n the horizonta l axis , we plot time. I f the middle o f th e visibl e spectrum , i s abou t on e strength o f a n electri c o r magneti c fiel d i s millionth of a meter (10~6m),soa20cm mirror is: measured vs . time, w e fin d tha t i t varie s in a 20x10-2 4 - 10' 6 -2x10-5 regular fashion , a "sinusoidal" patter n in fact. or 200,00 0 wavelength s o f gree n ligh t i n Note that the polarity changes and that the sine diameter. wave repeat s itsel f a t a specifi c rate . Thi s i s At 1000MH z ( a middle frequency i n radi o called th e frequency, measure d i n cycles per astronomy) the wavelength isaboutlOcm. Even second o r Hert z (Hz) . the Ver y Larg e Arra y radi o telescop e i n New Radio radiation, like all othertypes, travels Mexico ha s antenna s o f onl y 24. 5 meter s i n at th e spee d o f light , s o i f w e measur e a diameter. Thi s correspond s t o onl y 24 5 frequency, w e ca n calculat e th e physica l wavelengths a t 1000MHz , about equivalen t t o separation of peaks in the wave pattern. This is looking throug h a n optica l telescop e smalle r called the wavelength and it equals the speed of than a millimeter i n diameter! Now you begin to light divided by the frequency. In mathematical suspect that radio telescopes will never be able terms, we can put i t like so: to resolv e anything! a m eL A\ ,3.00 m) , 10 , »— Ai 1 ., <- For reason s becomin g a littl e mor e M H 7) apparent, radio telescope antennas (equivalent The wavelengt h o f ligh t i s muc h shorte r to the lens or mirror i n optical telescopes ) are than most of the familiar radio frequencies. For used as "flux collectors" rathe r than as devices example, for AM radio, the wavelength (\ = to form images. They collect energy, preferably

14 The largest radio telescope in Canada I s the Algonquin Radi o Observatory i n Ontario. strength o f th e signa l afte r bein g receive d by the antenna , compare d t o som e well-define d Un»» Of theoretical value. We can increas e the gain by Fore* narrowing th e radiatio n pattern , an d b y increasing th e receivin g are a o f th e antenna . Let's narro w the pattern first . A very narrow patter n i s a good thin g — it avoids confusio n a s t o wha t objec t i s bein g observed. I t also permits sweeping the antenna to produc e a crud e picture . I f a wir e o r ro d ElMtrtc Urw » of Fore* called a "reflector " i s place d paralle l t o th e dipole a t a critical distance and ha s a specific Direction at wivt i* out ol pag e length, an antenna design called a two element FIG. 1 lowird reirJrr Yagi i s formed , wit h a radiatio n patter n a s shown in FIG. 3. Again of 5db will be obtained. A decibel o r d b is a unit of power difference; it can b e thought o f a s analogous t o magnitude for ou r purposes . Th e decibe l scal e i s a logarith mic one— a gain of 5d bis almost 4 times the signa l power . A thre e elemen t Yag i i s formed b y addin g a wir e o r ro d calle d a "director" i n front of the two element antenna. This design ha s a gain o f 7d b at best, In the same manner, more directors can be added bu t wit h diminishin g effect . U p t o 1 0 FIG. 2 elements can b e added fo r a gain of 13db , but beyond thi s ther e i s n o significan t improvement. These antennas are sensitive to from only on e direction. Th e basic antenna is a radiation that is polarized in the same direction piece of wire strung in the air. Experimenters in as the rod s are oriented. If the rods are vertical, the early days of radio soon found that the wire the antenn a i s sensitive to vertically polarized became mor e efficien t i f i t wer e a n exac t radio waves . B y no w you'v e probabl y multiple o f th e wavelengt h the y wishe d t o recognized thi s typ e o f antenn a a s th e styl e receive. Th e standar d antenn a no w use d t o commonly use d fo r roofto p T V antennas, but define al l othe r antenn a design s i s th e "hal f the design has applications i n radio astronomy wave dipole " see n i n FIG . 3 . Thi s antenn a i s as well. directional i n a donut o r torus pattern at righ t Gain can also be increased by using more angles to th e wire. This i s called the radiation receiving element s lik e dipoles . Th e spacin g pattern, s o name d becaus e a n antenn a wil l between the m i s ver y critical ; wit h imprope r transmit radiation in this pattern — but they will spacing the incoming radi o waves cancel each receive radiation i n the same manner. other ou t instea d o f addin g together . Thi s The directivity o f the antenna i s the angle technique, whe n properl y done , effectivel y between the "half power " points of the pattern. increases th e receivin g area . I f a reflectin g The gain of the antenna is a measurement of the surface i n th e shap e o f a parabaloi d i s used, 16 mm ANTI I

•1/2 A

Two-Element Yagj. outpu t r*c«tv«» (ram thli direction

Radiation Patter n

Three-Element - dlpol i Yagi director

^-- dipol e 0" '•id* lob*i" or cllflrecticn Hn g Radiation Patter n

Radiation Patter n

then the receiving area increases dramatically, elements i n a radi o telescope need only b e in and the radiation pattern becomes very narrow. the orde r o f 1m m o r so . Fo r thi s reaso n i t Gains in excess of 30db are common. This is the becomes possible to to combine the ouputs of design use d b y mos t o f th e world' s radi o more tha n on e antenn a t o simulat e a "ver y telescopes. large" antenna . Usin g thi s technique , In comparin g radi o telescope s t o thei r resolutions o f minute s o r eve n fractions of a optical counterparts, we can even include the second of arc are practical. effects of diffraction. I n optical telescopes this Using a techniqu e calle d interferometr y effect ca n b e see n as the familia r diffraction much mor e information ca n be extracted from rings aroun d sta r images . I n radi o antennas, the signal. In this method, two or more antennas these sam e diffraction ring s are produced bu t are used , space d some known distance apart are called side lobes. and connected s o that their signals add. As an Since most radi o wavelengths are so long, object is observed, ti will also be moving relative the accuracy of the spacing between receiving to the antennas, and most of the time it will be 17 A CONTINENT-WIDE RADIO TELESCOPE

The instrument would be unique. I t would form video cassett e machine s fo r recordin g radi o images of the radio sky showing details as small telescope data . as 0.0004 arc seconds, approximately 100 0 times Each element o f the proposed VLBA would be better tha n eve n th e fines t optica l telescopes , a 25 m antenna , capabl e o f workin g i n a even surpassin g th e forthcomin g spac e wavelength rang e fro m 1.3c m t o 1 metre. Th e telescope. entire arra y woul d b e operate d fro m on e What is it? The radio telescope capable of such location, wit h eac h telescop e recordin g it s resolution woul d not b e a single instrument, but output o n 6-hour vide o cassette recorders. Th e a serie s o f eigh t antenna s locate d a t ke y technology fo r remotel y controllin g multipl e positions acros s Canada . Th e constructio n o f dishes has already been developed on a smaller this "Very-Long-Baseline Array,"as it is called, is scale in the U.S . for the Very Large Array in New being propose d a s th e nex t majo r projec t fo r Mexico. Canadian astronomy. The array would b e ideal All eigh t antenna s woul d b e locate d a t a for investigating powerful energy sources within latitude of 49.3 ° North , with spacing s designe d cores o f activ e galaxie s an d quasars , fo r so tha t combination s o f antenna s coul d b e observing the interstellar clouds where stars are utilized for a variety of baseline lengths. I t is not forming, searching for planetary systems around necessary t o locat e th e dishe s i n "radi o quie t stars, and even for research into the geophysics sites" sinc e an y unwante d loca l radi o nois e i s of th e earth . cancelled out when the signal is combined with

The antenna s o f th e proposed VLB A woul d b e situated a t eigh t location s across Canada. Th e sites of the Dominio n Radi o Astro- physical Observator y an d the Algonqui n Radi o Observatory ar e als o shown the output from another antenna. The majority of Canada is an ideal location for such a string of antennas would likel y be in western Canada. In radio telescopes because of the country's large addition, th e presen t radi o telescope s a t th e east-west dimension . A n undertakin g o f thi s Dominion Radi o Astrophysica f Observator y i n nature i s no t unprecedente d fo r thi s country , Penticton an d a t th e Algonqui n Radi o since Canadia n astronomer s wer e pioneer s i n Observatory coul d b e incorporate d int o th e the field o f long-baselin e interferometry . I n the system fo r specia l observations . Th e 100 m mid-60's, signal s fro m th e Algonqui n an d telescope at Effelsberg, Wes t Germany is also at Penticton radi o telescope s wer e "linked " vi a 49° North , and if tied into the array could giv e a synchronized videotap e machines . Sinc e then , baseline of over 120 ° i n longitude . this technique has been adopted by other groups The estimated construction cost o f the VLBA around th e world . is $23,000,000. The project is still in the proposa l In th e las t tw o years , Canadia n radi o stage, bu t i f approve d i t woul d creat e a astronomers hav e bee n th e firs t t o us e a significant advanc e i n ou r knowledg e o f th e communications satellit e t o lin k radi o universe, an d provid e a n excellen t researc h telescopes, an d th e firs t t o us e conventional opportunity fo r Canadia n science.

18 4 « A TYtPOOA L

Final • Ignal proc»iiing

moving at a different rate at each antenna. This O° Kelvi n (Absolut e zero o r -273°C) som e of causes the signal to add or subtract alternately, these electron s periodicall y wande r off . No w producing "fringes " jus t a s i n optica l consider a wir e (ou r antenna ) mad e o f thes e interferometry. atoms wit h periodicall y wanderin g electrons . THE RADI O TELESCOPE RECEIVER Electrons ar e electri c charge s (negative ) an d Most o f u s ar e familia r wit h radi o an d the flo w o f electrons i s what we ar e trying t o television receivers . Modern equipmen t take s detect. I f we watch the end of our antenn a we the for m show n i n FIG , 4 . A typica l radi o will se e electron s flowin g no w an d the n a t receiver consist s o f a serie s o f "frequenc y random intervals . This i s called thermal noise selective elements" that narrows the incoming because i t i s caused by thermal (heat ) energy inducing th e electron s t o wander . Th e signal dow n t o jus t th e frequencie s w e ar e interested in , intersperse d wit h amplificatio n magnitude o f th e nois e i s expresse d mathematically by : stages. A t the end of the proces s the signal is converted into a usable form by rectifying it in a "detector" stage . The detecto r i s followed b y Vrms = V^KTRB either a n audi o amplifie r (a s i n a n ordinar y Vrms - nois e voltag e (AC ) household radio ) o r specia l processin g K - Boltzmann' s Constan t circuitry (a s in a radio telescope). T = temp. i n °K A typical radi o reciever will detect a signal R = resistance o f wire from the antenna of only .2 5 /W (a quarter of a B = bandwith millionth of a volt). This is only about 10~ 15 watts or a thousandth of a millionth of a millionth of a This nois e i s a continuou s spectru m i n watt! Unfortunately , eve n a t thi s leve l o f frequency; i f w e could hea r it , it would soun d sensitivity, only about 8 celestial "radio objects " like his s or "white noise. " Nois e o f this nature are visible or detectable! The y ar e listed i n the can b e reduced b y : back sectio n o f th e RAS C Observer's -- reducing the resistance of the wire (which is Handbook. Wh y can' t w e jus t ad d mor e unfortunately no t possible due to the nature of amplifiers t o mak e ou r receive r (telescope ) the antenna) more sensitive? The answer to that gets us into -- reducing th e temperature the realm of the sub-atomic particles . — reducin g th e bandwidt h Matter i s compose d o f atoms . Atom s are For reason s we'l l com e acros s late r on , composed o f a nucleu s wit h a clou d o f reducing the bandwidth i s not desirable, so we electrons surrounding it. At tempertures above are left with "refrigerating" th e antenna and, in 19 "Even a n automobile ignitio n 15k m awa y wil l rui n some radi o observations. W e are indee d speaking of tremendous sensitivity."

practice, th e initia l R F amplifier . Mos t radi o characteristics as the antenna i s swept across telescopes hav e th e radio-frequenc y o r "RF " the object . B y modifyin g th e receiver , i t i s amplifier a t th e antenn a itself , wher e i t i s possible t o rapidl y swee p it s frequenc y o f immersed i n liqui d nitrogen , o r eve n liqui d operation a s well , permittin g a "spectru m helium! The reaso n for these drastic measures analysis" to b e made. is that th e first amplifier ha s about 95 % of th e The signal s produce d b y mos t celestia l effect of setting the nois e value in a receiver. !f radio source s are similar to ou r thermal nois e the nois e i s ba d a t th e R F amplifier stage n o sources in that they are composed o f impulses amount o f fancy circuitry wil l improv e i t later producing a continuum o f frequencies. At one on. So most telescopes have very expensive RF specific frequenc y ver y littl e powe r i s amplifiers and only ordinary electronics for the produced, bu t i f th e receive d bandwidt h i s remainder of the receiver. As an exam pie, with a made as large as possible, then the strength of bandwidth o f 10kH z an d a 5 0 O antenna , the receive d signa l wil l increase , makin g i t reducing th e temperature from 273°K (0°C) to easier to detect. This i s why large r bandwidths 10° K (th e temperature of liqui d nitrogen), the are desirable , eve n thoug h the y mea n mor e noise become s on e hundre d time s lower. The noise. signal-to-noise rati o i s improve d b y 15db , As i t turn s out , ther e ar e certai n something tha t hi-f i fan s wil l b e abl e t o "preferable" frequencie s i n radi o astronomy , appreciate. ones a t whic h th e commo n interstella r atoms and molecule s lik e t o radiate . Throug h ANALYZING THE SIGNA L international agreement, astronomers have had Once you have a signal emerging from your bands around thes e importan t frequencie s set receiver, yo u hav e t o recor d an d analyz e it . aside fo r radi o astronom y onl y (n o radi o There are several types of analysis or observing transmitters o r "light pollution" allowed). Even programmes tha t th e radi o astronome r ca n so, radi o interferenc e i s a definit e problem , carry out . H e or she can loo k for: since eve n a n automobil e ignitio n wil l rui n — Amplitud e variation s a t on e frequency o r a t observations u p to 15k m away. We are indee d all frequencie s speaking o f tremendous sensitivity . — changing amplitud e wit h frequenc y With th e radi o communication s spectru m ~ changing frequency wit h tim e overcrowded already , radi o astronom y ma y -- phas e change s wit h tim e face a crisis in spectrum pollutio n lon g befor e -- polarization of signal an d changes with tim e optical astronomy . ~ spatia l variation s i n signa l strengt h (i.e. : sweeping the sky to produce a map of any of the above variations) ED. NOTE: I n this article Dave has covered th e The informatio n extractio n i s don e b y basics of radio telescope design. In an article computers, an d thi s equipmen t i s secon d i n scheduled for an issue next summer, Dave will expense onl y t o th e antenn a i n mos t continue the discussion by delving into the installations. Th e computer produce s th e sor t specifics o f th e design o f amateu r radio of prett y "radi o pictures " see n i n Astronomy telescopes and the objects that can be received. magazine. I t does thi s b y analyzing th e signa l So, stay tuned! 20 io/c new /

THIS I S YOUR LAST STARDUST...... if your nam e is not on this list of paid-up With th e larg e numbe r o f ne w member s RASC members as of Nov. 15,1980. (If you have added t o las t year's membership, w e currently renewed you r membershi p betwee n Nov . 1 5 have 120 RASC members receiving Stardust. If and the time you received this issue.then please everyone who was a member last year (1979-80) ignore thi s plea . O f course , subscribers t o renews thi s year, w e have the potential for the Stardust nee d no t b e concerne d abou t highest membershi p figure s in our Centre' s membership renewa l either.) history. A. Abbott M . Leenders Please rene w you r membershi p befor e S. Adamson N . Leenders Dec. 31 , 198 0 i f possible , t o ensur e a n K. Atchlson A . Lowe uninterrupted suppl y o f Stardusts, RAS C Journals, an d Newsletters, an d th e 198 1 D' Aufler D . MacDormand Observer's Handbook. Fee s can be paid to ou r D. Baker C . Makarowski D. Beal e R . Marti n Treasurer, Me l Rankin , a t th e Decembe r 8t h J- Belm a E.B.McDonoug h General Meeting , o r b y mai l wit h th e hand y D. Belcher P. McMillan form on the insid e bac k cover. K. Berglund J. Musgrave Tired of being pestered every year for those B. Butler annual RAS C dues ? The n wh y no t conside r S. Nunwelle r T. Cadle n taking ou t a Life membership ? Fo r $200, your A. Platano w R. Carrier Life membershi p pay s fo r itsel f i n 1 0 years at W. Polloc k R. Carson today's rates , bu t thos e annua l fee s ar e G. Prideaux M. Clark e guaranteed t o increas e i n th e nex t couple o f L. Priest R.J.Connor years. C. Constant M. Rankin V. Cottrel l E. Rask o OBSERVERS PRESEN T THEI R GREATES T D. Cross L. Rodes HITS D. Routledg e A. Dyer At th e Novembe r 3 Genera l Meeting , N. Rowlands several member s regale d th e 5 0 o r s o i n D. Elli s J. Rusch attendance wit h som e super b result s o f thei r G. Flnle y A. Whyte observing, astro-photography , an d telescop e H. Gibbon s D. Wlndrum making activities. Fo r example, Mar k Leender s J. Wooley B. Heartwel l amazed everyon e b y demonstratin g hi s D. Holmgre n L. Yaklwczuk completed 15c m (6" ) refracto r wel l befor e th e W. Yeung previously schedule d completio n dat e o f R. Kin g J. Klassen M. Zalcik October, 2004 ! Crai g Makarowsk i als o se t u p S. Krysko his shoe-string-budget 25c m (10" ) Newtonian . R. Kunze Another telescopic attraction was Roger Hunt's new 13.1 " Odyssey 1 Dobsonian reflector from As of Nov. 15,1980, 54 people were paid up Coulter. For many this was their first encounter members of the Edmonton Centre, including 8 with a real live Dobsonian . Life members. Compare this to last year's total Stew Krysk o playe d th e infamou s membership of 99, and you can see that we still "Kleopatra tapes " which recorde d fo r al l time have a lon g wa y t o g o i n gettin g al l thos e the soun d o f tw o chipmunk s observin g a n procrastinators out there to send in their dues. asteroid occultation. —continued

21 The RAS C i n ' RASC NEWS continue d

* MONlht y Dave Beale , Dav e Belcher , Bo b Kin g an d * obsERVJN q ACTIVITIE S Andrew Low e sorte d throug h umptee n * 6 ISSUE S of SiARdus i incompatible slid e projector s t o presen t a * ih E 8 1 ObsERVER' s HANdboo k beautiful collectio n o f astro-photography, of a * iM t COMplETJO N O f OUR 17,5 " TtUsCOp E quality tha t deserve s to grace the pages of the * PhAS E 2 of Buc k MOUNTAI N glossy astronomy magazines . To conclude th e * STARNICH T '8 1 I N MA y evening, th e Observer' s Grou p leader , Dav e * T!I E Viciom A C.A . JI N JUN E Holmgren, tol d u s of hi s obsession wit h faint, * FRE E PlANETARit M Adwissio N fuzzy galaxies that fluctuate i n flux. * 6 ISSUE S o f ih e JOURNA ! & NATJONA ! NEWS!ETTE R A RECORD ATTENDANCE ? While w e hav e n o officia l records , th e ALL THI S AN D MOR E FO R ONLY attendance at October's General Meeting must $20.00 ($12.0 0 FO R Thos e UNC|E R 18 ) have bee n nea r record-breakin g levels . Some PlcAsc RENE W youR MEMbERshipbEfoRE Dec. 71,1980. 90 members , guests , visitors , an d QE P astronomy cours e registrant s were present to hear a fine talk b y Dr . Gordon Rostoke r of the U.of A . on th e topic, "Aurora : Violenc e in our Skies." DONATE TO YOUR FAVORITE CHARITY -US! The Edmonto n Centre , RAS C i s no w officially registere d with Revenu e Canada as a non-profit charitabl e organization . This status will b e of enormous value to u s in the years to Q.E.P. come for fund-raising program s and solicitin g donations. Astronomy ROLF MEIER'S HAT TRIC K Yes, he' s done i t again ! Rol f Meie r o f th e Courses Ottawa Centr e ha s discovered hi s third come t in onl y tw o years . Designate d a s 1980q , thi s - Introductor y Astronomy - comet will reach perihelion on Dec. 9,1980 at a - Advance d Leve l Astronomy - distance o f 1.5 2 Astronomical Units . Her e ar e estimated position s and magnitudes fro m IA U - Telescop e User's Seminar - circular 3539 : R.A. Dec. Mag. Dec.7 17h54m +28° 26' 10.1 Dec.12 17h53.7m +27°05' Phone Stew Krysko at the Planetarium Dec.17 17h53.5m +25°54' 10.3 for mor e informatio n (455-0119 ) Dec.22 17h53.3m +24° 53' Dec.27 17h53.2m +24°OV 10.4 This places the comet in southern Hercule s for th e remainde r o f the year. 22 at th e planetariu m

Halloween Nigh t sa w the premier e o f ou r have take n plac e sinc e th e initia l desig n new show, Illusions. The public response to the sketches were published i n Stardust back in the show so far has been excellent, in terms of both summer. Bot h th e exterio r desig n an d th e attendance and comments. The strong point of interior layou t of the building ar e considerably illusions i s it s variet y — it ha s it s seriou s an d different i n detail now, though the main shape eerie moments, interspersed liberally with a few and concept of the structure has been retained . laughs. Pleas e tr y t o catc h thi s programm e Ian McLennan , wel l know n t o man y RAS C before i t closes Feb. 22 . members a s the first director o f th e QEP , ha s Accompanying Illusions during Novembe r been assigned the task of assembling a design was a 12-minut e "mini-show " calle d team fo r th e larg e exhibi t gallery . Som e very Discoveries tha t deal t wit h curren t scienc e exciting idea s are coming togethe r i n this area news ~ item s lik e th e ne w theory o f earthly as well. rings, Mt . St . Helens , SS433 , th e mysteriou s Finally, Planetariu m staf f member s wer e March 5 gamma-ray burst, the European comet able t o witnes s the Voyage r fly-b y o f Satur n probe, an d hunter-kille r satellites . Beginnin g as-it-happened, thanks to a dish antenna set up about th e firs t wee k o f December , this new s at a loca l vide o stor e t o receiv e th e direc t show will be replaced with one of similar format, satellite broadcast s transmitte d b y NASA . A but dealin g strictl y wit h Voyager . Throug h total o f 6 hour s o f Voyage r coverag e wa s mini-shows o f thi s natur e w e ca n kee p th e captured out of the sky from a communications public informe d o n scientifi c discoverie s and satellite and put on videotape. (As it turned out, theories while the y remai n in the news. these program s were available on a Canadia n Illusions an d th e Voyage r mini-show wil l cable channel but on a delayed basis and with a continue throug h Christmas . For the first time highly unpublicized schedule, since the federal in the 20-year history of the QEP, we will not be government decided to allow their broadcast in presenting a special Christmas show. Ou r K- 1 Canada only a matter of hour s befor e the first school sho w A Fantasy o f Stars wil l b e program was to begin.) I t wasan exciting 3days presented at 1:3 0 pm each day from Dec. 22 to in mid-November, seein g Saturn and its moons Jan. 4 (except Christmas and New Year's Day). revealed for th e first time vi a live satellite TV. This shoul d appea l t o thos e wit h youn g children lookin g fo r holida y activities. The fall serie s of astronomy courses went very well , wit h overal l community astronom y attendance up considerably from last year. The annual Junior Astronomy Clu b which began in October wil l b e continuin g o n Saturda y mornings a t th e Planetariu m i n December . Ideas fo r som e ne w communit y astronom y programmes fo r 198 1 are materializing , ideas like noon-hou r astronom y talk s downtown. A new serie s o f astronom y course s star t i n January; contac t Ste w a t 455-011 9 fo r mor e information. Plans for th e ne w Spac e Sciences Centr e Video technician s preparin g a dis h antenn a fo r th e are progressin g ver y quickly , wit h revise d reception o f NASA/JP L Voyage r program s direc t drawings appearing every week. Many changes from a geosynchronous satellite . 23 look boc k tim e year/ og o

JANUARY, 1881 : JANUARY, 1931 : "The so-calle d Nov a of 1600 , which i s 34 "Le planete Mars b y E.M . Antoniad i i s Cygni of Flamsteed, and P Cygni of Schonfeld's unquestionably on e o f th e mos t importan t catalogues of variable stars, was discovered by books on Mars ever published, and it will remain Wilhelm Janson, a pupil o f Tycho Brahe's, and always a standar d wor k o f referenc e for th e entered upo n hi s globe i n that year. It has been period covere d b y th e author' s researches . erroneously stated in some astronomical works Chap. // ' contain s a n accoun t o f instruments , (as i n Cassini' s Elements d'Astronomie) tha t stations an d condition s mos t favorabl e for a Kepler was a co-discoverer of this star, of which successful study of this interesting planet. It will he himsel f inform s u s t o th e contrar y i n hi s be noted her e that M . Antoniadi — who firs t in treatise publishe d i n Pragu e i n 1606 . Keple r 1909 ha d th e immens e advantag e o f usin g gave the position of the star for the position of systematically fo r th e stud y o f Mar s th e grea t the star for the end of 1600 in R.A. 300° 46', Deck 32.7-inch refractor of the Meudon Observatory +32°52'. H e observed it during nineteen years; -- himself prefers refractors to reflectors, but it it becam e fainter i n 1619 , and disappeare d in will be something of a surprise to some readers 1621, thoug h Fortun i Licet i date s a that h e doe s no t conside r th e secondar y reappearance i n tha t sam e year . I n 165 5 spectrum a serious drawback i n the use of such Dominique Cassin i observe d i t again ; i t instruments for planetar y work . The following increased during fiv e years, until it attained the chapter contain s detail s o f th e orbita l an d third magnitude , an d afterwards diminished. " physical elements of Mars, after which we come to a general account of the surface features as telescopically observed , includin g change s o f JANUARY, 1931 : "The Adle r Planetariu m i s a ne w an d colour, "th e illusio n o f th e canals, " th e pola r caps, cloud s an d othe r atmospheri c striking featur e on th e shor e betwee n a small phenomena, the habitability o f the planet, and lagoon and Lake Michigan (i n Chicago). In plan the two satellites. This concludes the first part it i s a dodecagonal: the walls face d wit h large of the volume. slabs o f re d granite an d i t i s surmounted b y a dome. Th e principl e objec t o f th e ne w It was the wonderful views of Mars with the institution i s explaine d o n th e dedicatio n great telescop e a t Meudo n whic h le d t o th e plaque tha t confront s th e visito r whe n h e author's fina l conclusio n tha t th e so-calle d crosses th e threshol d o f th e entranc e 'canals' o f Scniaparelt i an d Lowel l wer e lobby....For thi s purpos e th e principl e illusionary, i n the sense that their geometrical instrument i s a large projection apparatus built appearances wer e th e resul t o f optica l an d by th e fir m o f Zeis s by which larg e audiences physiological causes . Another poin t whic h M. can watc h th e movement s o f th e starr y Antoniadi's researches--and, indeed, the work firmament a s projected upon the insid e of the of man y othe r observers , lik e Prof . W.H . great dome of 68 feet in diameter. On the north Pickering — reveal that, despite its shortage of and south sides of the dome are two spacious water, Mar s i s b y n o mean s a s ye t a dea d exhibition halls, while to the east of it are library, planet." lecture an d work-rooms, an d also the office of —Edited from Nature the director, Dr . Philip Fox. " Compiled by Ton y Whyte 24 uihoiV up ? onon ••

Orion, perhaps the most spectacular o f all the constellations, straddles the celestial equator an d dominates the sky for observers worldwide .

** CLAS S I OBJECTS ** Burnham's has "much complex interior detail." Bright, easy to find It's proximit y t o £ Orionis , th e lef t sta r i n Within Orion' s swor d lie s on e o f th e Orion's belt , cause s a problem, though. Glare brightest nebula e i n th e entir e sky , M42, the from thi s sta r often washes out th e nebul a i n Orion Nebula. In a pair of binoculars it appears less than perfec t skies. as a nebulous patch . In a very small telescope it Just 2° north and a little east of £ Orionis is looks lik e a greyish haz e across the eyepiece . M78, an 8th magnitud e smudge . This i s one of But given a 15 or 20cm telescope, a magnificent the rare examples of a bright reflection nebula - greenish glo w wit h intricate swirls and details M78 shines by the ligh t reflecte d from nearb y spans th e field . Thi s i s obviously on e o f ou r stars, and not by glowing hydrogen gas. M78is Class I object s thi s month . Eve n vetera n small, only 8' x 6 ' in size. deep-sky observers return to the Orion Nebul a Moving to the northeast corner of Orion, we season after season, since one can never see all come across an open cluster, NGC 2194, one of the detail presen t in this celestial showpiece at many i n the winter Milk y Way. This one is well one observin g session . M4 2 i s liste d i n worth the search, being large and fairly rich. It Burnham's a s 5th magnitude . A t a n ideal site, contains about 10 0 stars which combine to give therefore, i t should appear to the unaided eye NGC 2194 a magnitude of 9. as a fuzzy star. Our next object, M43, isactuallyadetached ** CLAS S III ** portion o f the Orio n Nebula . Novice observers Challenge objects will ofte n se e this objec t withour realizin g its Of al l th e challengin g deep-sk y objects , identity. It is located just north of the larger and there i s non e mor e famous, nor mor e difficult more impressive M42. than ou r firs t Clas s II I objec t thi s month . Another candidate fo r Clas s I this month is Extending southwar d fro m £ Orioni s i s th e a regio n o f nebulosit y tha t carrie s three NG C famous Horsehead Nebula. It is extremely faint numbers, NGC 1973/5/7. This object is a bluish and ver y large , abou t 1 ° i n length , wit h £ reflection nebul a a degree o r s o north o f th e Orionis o n th e norther n end. The Horsehea d M42/M43 pair . Wit h suc h spectacula r area contains two objects , an emission nebul a neighbors nearby , NG C 1973/5/ 7 i s usuall y called 1 C 43 4 an d th e dar k "horse' s head " neglected, bu t i t i s a fine nebulou s are a in it s nebula itsel f calle d B33 . For thi s on e ma y I own right . recommend at the very least a 20cm Rich Fiel d Telescope, a goo d dar k sit e an d perhap s a ** CLAS S II ** nebula filter . Th e glar e fro m £ Orioni s ma y Fainter, but distinctive once agai n pos e a problem — try keepin g thi s We can star t Clas s II off wit h yet another star out of the eyepiece field to the north . diffuse nebula, NGC 2024 . It is easy enough t o NGC 202 2 i s a littl e 12t h magnitud e find a s it occupies th e sam e field of view as £ planetary nebul a locate d betwee n A an d a Orionis. I t is about 20 ' in size and according t o Orionis. Bein g about 25" across, this planetary 25 Constellation Chart courtesy of Hubbard Press DEEP-SKY OBJECT S

OBJECT TYP E MAG . SIZ E

Class 1 • •

M42 E N 65' M43 E N 20X15' NGC 1973/5/ 7 R N 40'X25

Class I I

NGC 202 4 EN M78 RN NGC 219 4 OC 9 8 ' is starlike in appearance at low powers, but i s not that faint. We've seen it in the Ellerslie 20cm Class II I — refractor. Finally, fo r a n objec t tha t definitel y 1C 434/B33 EN + represents a challenge , try anothe r planetary Dark N - called J320 . Burnham' s list s i t a s "ver y faint , small, and round,"or more precisely, 13th mag., NGC 202 2 PN 1 2 25" and 10" in diameter. It is plotted on the Skalnate J320 PN 1 3 10" Pleso Atlas of the Heavens, but it is not labelled. It lies about 3° east of ir k Orionis, butfrom there use a good sta r atlas! OC Open Cluster As a footnote , w e migh t ad d tha t Ke n GC Globular Cluster Hewitt-White in Vancouver reports seeing one EN _ _ Emission Nebula of las t month' s challeng e objects, the Bubbl e RN Reflection Nebula Nebula. He was using the 16" f/5 reflector of the PN.... Planetary Nebula Ottawa Centre's India n Rive r Observatory , but reports tha t the object was barely visible. -- Ste w Krysko the /olo r /y/te m

THE TRIPLE CONJUNCTIO N 1° sout h o f Saturn , whil e bot h planet s ar e In 198 1 w e will b e abl e t o witnes s a rare moving westward or "retrograding. " Jupite r is astronomical event — atriple conjunction of two at opposition o n March 25, Saturn on March 26. planets, i n thi s case , Jupite r an d Saturn . O n The third conjunction occurs on July 30 , 1981 January 14,1981 , Jupiter will pass only 1° south as Jupite r overtake s Satur n whil e movin g of Saturn, with both planet s in the morning sky eastward. The pair of planets will be visible low in Virgo. On Feb. 19,1981, Jupiter again passes in the west after sunset in lat e July. 26 ob/erving report /

CHASING ASTEROIDS October an d Novembe r wer e "asteroi d occultation" month s fo r observer s in Alberta. On Nov . 23 , th e asteroi d 13 4 Sophrosyn e passed in front o f the 8th magnitude sta r SAO >M 74963 i n Triangulum . Whil e th e mai n iif'1 occultation pat h was predicted to pass through the southern U.S., astronomers all across North America wer e asked to observ e the event , in case an y unexpecte d secondary occultation s occured du e t o unknow n satellite s orbitin g Sophrosyne. A s o f thi s writing , observer s i n Edmonton wer e plannin g t o tak e par t i n thi s event and a complete report will appear in the next issue. Earlier, i n th e we e hour s o f Sunday , October 26 , the asteroi d 1 2 Victoria occulte d the 9.8 mag. star BD+1° 2457. This event should have bee n visibl e fro m centra l Afberta . Observers both in Edmonton and Calgary were -i- ready t o fa n ou t acros s th e provinc e fo r tha t event, bu t cloud s mad e shor t wor k o f A photometri c tracing of th e ligh t dro p durin g th e everyone's plans. Kleopatra occultatio n Oct. 1 0 obtained by Dr. Dou g Better luc k wa s ha d o n th e nigh t o f Oct . Hube at the Devon Observatory. 9/10, when 216 Kleopatra occulted the 8.8 mag. star SA O 12806 6 i n Pegasus . Calgary Centr e observers were at thei r post s a t the predicted Nevertheless, Dr. Doug Hube at the U.o f A. time, but misse d seeing the occultation a s the Devon Observatory , acquire d a super b path passe d wel l t o th e wes t o f al l thei r photometric tracin g o f th e 11-secon d observing groups. disappearance o f th e star . (Se e above ) Th e In Edmonton , w e wer e mor e fortunate. 5 undersigned, alon g wit h Ste w Krysko , observing team s wer e hastil y arrange d an d stationed jus t wes t o f Tolfiel d o n Hwy . 14 , stationed roughly on an east-west lin e aroun d observed a 6-second disappearance, with some Edmonton. We say "hastily", since the word that unusual flickering at the end of the event. If this the occultation path had shifted to pass over us was real, then we may have observed some sort reached Centr e members only a few days prior of "grazing occultation", as it is thought that we to the event. Originally, we were thought to be were nea r th e eas t edg e o f th e asteroid' s too fa r eas t to se e anything, an d n o amateur shadow path . observations ha d been planned . A full repor t ha s been submitted to Davi d Of th e 5 groups, only tw o acquire d usefu l Dunham o f th e Internationa l Occultatio n data. People at 2 of the stations missed seeing Timing Association . I f ther e ar e other s the event entirely for reasons too embarrassing interested i n participatin g i n mor e asteroi d to publicize . A thir d grou p saw the even t but chases in 1981, please let us know. It's great fun! failed to properl y recor d the pertinent data . — Alan Dye r 27 ob/erving cictMtie /

The pas t tw o Observer' s Corner meeting s prepared t o kee p warm! featured shor t talk s on telescop e makin g and JANUARY using. Crai g Makarowsk i spoke at the October meeting o n th e constructio n o f hi s 25c m The O.C . fo r thi s mont h i s o n Monday , Newtonian telescope , a well-built devic e with January 26 , beginning a t 8:00 pm a t the usua l many part s scrounge d resourcefull y from th e location of Rm . 445 in the U.of A. Physics Bldg. junk yard . Rich-fiel d telescop e observin g i s Our feature d speake r i s long-tim e Centr e something no t many of us have done, but at the member an d activ e observer, Mark Leenders, November O.C. , Stewart Krysko enlightened us speaking on "Telescopes I Have Known. " (!) on the special techniques an d problems . We hav e bravely scheduled a n Observing Unfortunately, w e mus t apologiz e for th e Session fo r th e dea d o f winter ! Hopefully, th e slight inconvenienc e caused to a few members night will be clear and not unbearably cold. On on th e nigh t o f Saturday , Nov . 1 . A "sk y Saturday, Jan . 2 4 we'l l b e a t th e Ellersli e familiarization session " wa s planne d a t th e Observatory fo r a n evenin g of genera l winter Ellerslie Observatory . A s i s al l to o ofte n th e observing. This i s a last quarter moon night . case, the skies were quite cloudy al l night, and If yo u requir e direction s t o th e Ellersli e so n o on e fro m th e regula r grou p o f vetera n Observatory, o r nee d a ride, pleas e call me. observers went out. About 8 or 9 new members - Dav e Holmgre n (436-2398) did venture out, however, only to find the place deserted. Pleas e accep t ou r apologie s - - bu t also pleas e not e that i f a scheduled observing night turns out to be cloudy, then the session is of cours e automaticall y cancelled . (Now yo u The 198 1 tell u s ! ) O n night s whe n th e observin g conditions are questionable, (i.e . some haze or I Observer' s Handbook I broken cloud), please phone the Observing Co- The Indispenslble publication ordinator fo r a fina l decision . Hi s numbe r i s always listed at the end of this column. We trust for all observer s that straighten s ou t an y question s - - i f no t please phone Dav e o r Centr e Presiden t Te d Cadien (463-1703) . --AP D Copies should be available at the December 8 General Meeting, but to only DECEMBER | those who have paid their RASC dues for Since ou r regula r 4th-Monday-of-the - 1981 ! Ensure yourself a copy of the month slot for Observer's Corner meetings falls Handbook ' . RENE W NOW. on Dec . 22 , to o clos e t o Christma s fo r mos t people, ther e wil l b e n o O.C . meetin g thi s month. There is an Observing Session, however, at Use the form opposite, and mall ft along wHh your the Ellersli e Observator y o n Saturday , Dec. 13 fee remittanc e TO: The Edmonton Centre, RASC; starting around 8:0 0 pm. This i s a first quarter _ c/ o th e Queen Elzabeth Planetarium; CN Tower, moon nigh t (th e moon look s spectacular i n the I lOtf i Floor ; 10004- 10 4 Avenue; Edmonton, AB. | 20cm refractor!) and also the peak night for the 151 OKI Geminid meteo r shower . Thi s i s on e typ e o f observing you don't need a telescope for, but be 28 ThE RoyAl DISCOVER ASTRONOMICAL SociEiy Of CAiNAcl A UNIVERSE EDMONTON CENTR E

monthly genera l meeting s monthly observer s grou p meeting s regular grou p observing session s use o f th e Ellersll e Observator y the annual RASC Observers Handbook STARDUST the RAS C Journal an d Newsletter free admission to all Planetarium shows

President Te d Cadle n Vice-President Dav e Belche r Treasurer Me l Rankl n

RASC, EDMONTON CENTRE MEMBERSHI P APPLICATION FORM Please accept m y application for membership m the Royal Astronomical Society of Canada. EDMONTO N CENTRE for 1981 . Enclose d is a cheque or money order for the appropriate fee; $20.00 for Adults; $12.00 for Youths 1 7 and under I understand that upon receipt of my application an d fee remittance, a membership card and a copy of the 198 1 Observer's Handbook will be mailed to my address (or can be picked up at the next monthly general meeting) , and that I will be placed on the mailing list s for RAS C publications.

Name D Ne w Member Address, G Renewa l

Postal Code Phone MAIL TO : Edmonto n Centre , RAS C c/ o Quee n Elizabet h Planetariu m C N Tower , 10t h Poo r 10004 - 10 4 Avenue Edmonton , Albert a TS J OK1 . Please make all cheques payable to : Edmonton Centre , R.A.S.C Thank * I STARDUST EDMONTON CENTRE, Royal Astronomical Society of Canada c/o Queen Elizabeth Planetarium 10th Floor, C.N. Tower Edmonton, Alberta T5JOK1

DECEMBER I JANUARY GENERAL MEETING S Music Room , Edm . Public Librar y

Monday, December 8, 8 PM Monday, January 12, 8 PM Mr. Alan Dye r Mr. Frankly n Loehcie "Collecting Starlight: An Introduction to Deep-Sk y "The Universal Key" Observing"

OBSERVER'S CORNER S Rm. 445, 4th Floor , Physics Bldg. , U . of A .

There will be n o O.C. gatherin g i n Dec. Monday, January 26 , 8 PM MERRY CHRISTMAS! ! Mark Leender s "Telescopes I Have Known"

OBSERVING SESSIONS

Sat.. Dec. 13 at 8 PM Ellersli e Sat., Jan. 24 at 8PM.... (Geminid Meteor Observing) (General Winter Observing)

CANADA ' TO: 15