the newslette r o f th eQUEEN ELIZABETH PLANETARIU Mand theEDMONTON CENTRE, RAS C

JUNE/JULY 198 1

75$

•Sunset ove r La s Campanas

Journey to the stars this summerat the

Queen Elizabeth Planetarium

A GALAX Y CD F ONEPeople used to believe in demons and dragons. Now these beasts have been replaced bya modem mythological creatur e — the alien from outer space. Are there intelligent beingsout there? Is there life on other planets? So me recent research suggests that we may live in agalaxy of one.

SUMMER STARLIGHTDuring the summer months people journey to far away places on their vocations. But haveyou ever explored the sky above you each and ever y night? In "Summer Starlight" we'llpoint out the prominent planets, stars, and constellations visible during summer.

A FANTAS Y OF STAR SA special show for special people, children ages 3 - 7, "A Fantasy of Stars" follows theadventures of Harold the Hero as he searches for Queen Cassiopeia, the only person whocan sav e his planet called Noctophobia wher e everyone is afraid of the dark.

FOR MORE INFORMATION, CALL455-0119

Stardust JUNE/JULY 198 1

EditorAlan Dye r

Assistant EditorSttwirt Kry»k o

ContributingEditors

T*d Cad!«nJohn Haut t

Dan Holmgre nAndrew Low*

Rod McConnsllAnthony Whyt e

TypesettingLorna Milllgan

Graphic ArtsDave BtlcherRick Corrtgan

Printed by

The City OfEDMONTONParks an dRecreation

12

14

246

1718212325

Vol. 2 6 No . 4

The Souther n Skies of the Andes Kare n FinstadThis region is one of the world's best astronomical sites; the dry air andclimate provid e marvefousl y clear an d steady seeing .

Radio Astronomy for the Amateur Dav e BealeIf you are interested in this area it can be very rewarding sinc e it is a field ofinvestigation rarel y attempte d b y amateurs .

Constructing an Astrograph ...Dav e BelcherWouldn't i t be nice to cove r one hundred squar e degrees o f the sky on asingle exposur e with a scale of 1 ° pe r inch ?

The Fron t Pag e Fro m the Editor's Termina lDiscoveries Astronom y New s UpdateAstronomy Basic s Wher e is the Moon Tonight ?RASC New sGeneral Meeting Notic eAt the Planetariu mLook Bac k Time 5 0 and 100 Years AgoWhat's Up ? Sagittariu s

COVER: Ther e ar e a fe w location s i n th e worl d considere d the bes t site s fo rastronomical observing . One of these is the western peaks of the Chilean Andes. TheEuropeans an d American s al l hav e installation s i n thi s area , a s does Canada . Th eUniversity of Toronto operates a small 61cm telescope at Las Campanas. Depicted onthe front cover i s a sunset ove r one o f th e La s Campanas domes. In this issue, KarenFinstad tells us what i t i s like to observe from that southern latitude.

STARDUST, the newsletter of the Queen Elizabeth Planetarium and the Edmonton Centre, RASC, ispublished bi-monthly and is available free to all members of the Royal Astronomical Society ofCanada, Edmonton Centre as a benefit of membership. Single copies are available at the PlanetariumBookstore for 75c. STARDUST is also available by subscription for $4.50per year for 6 issues ($9.00for two years for 12 issues). Please make all cheques or money orders payable to: The QueenElizabeth Planetarium. Write to: The Editor, STARDUST; do Queen Elizabeth Planetarium: CNTower Wtti Floor; 10004 - 104 Avenue: Edmonton, Alberta, T5J QK1. Unsolicited articles orphotographs pertaining to any aspect of astronomy are welcome.

IhefroAlpage

From The Editor's TerminalAs in previous years, the summer is once again shaping up to be a

busy time for amateu r astronomers in the Edmonto n area. There iscertainly no lack of things to do, places to go, conventions to attend,and projects to work on. For example, in this issue you'll find detailson 3 astronomical events, each located at a different "mountain."

First, i s th e annua l Summe r Solstic e Celebratio n a t Buc kMountain. A s everyon e likel y know s b y now , perpetua l twiligh tessentially prevent s any observing (other tha n lunar an d planetarywork) around solstice time. Instead, we utilize our observing site atBuck for a night-time campfire gathering, weiner roast, and outdoorparty. Everyon e i s invited, For more information, call Ted Cadien at

Secondly, ove r th e Augus t lon g weekend , amateurs from theEdmonton and Calgary Centres and from the Medicine Hat Club areplanning t o gathe r on top o f 8000-foot Plateau Mountain fo r 2 or 3nights of first-class deep-sky bberving. Plateau is about 150km south-west of Calgary in the Livingston Range of the Rockies. The sceneryalone i s wort h th e visit . Fo r mor e details , phon e Dav e Beal e a t4740811.

Thirdly, i f yo u ar e no t heading down to Platea u on the Augustlong weekend , why not make a trip out to Riding Mountai n Nationa lPark i n Manitoba ? Th e Winnipe g Centr e is hostin g the "Manitob aAstronomical Convention " ami d the beautifu l lake s and wood s ofRiding Mountain . Th e skie s ar e sai d t o b e ver y dark . Fo r mor einformation, contact , Gu y Westcott , Winnipeg Centre , RASC , c/ oP.O. Box 174 , St. James P.O., Winnipeg, Manitoba , R3 J 3R4.

On to p o f al l thes e events , don' t forge t th e RAS C Genera lAssembly in Victoria June 26 - 29. See your recent issues of the RASCNational Newsletter fo r information .

During th e summer , wor k wil l als o continue o n preparin g th eBuck Mountai n sit e fo r th e establishmen t o f ou r observin gheadquarters ou t there . I t no w look s a s i f th e Centre wil l b epurchasing a n ATCO-style trailer uni t for placement at Buck, ratherthan constructing a building from scratch or from a kit. Assistancefrom Centre members on this project and on the construction of our45cm (17.5") Dobsonia n scope would be welcome. Again, phone TedCadien.

The last item I wish to bring to your attention is the new format forour bac k cover . I n a n attemp t t o presen t a cleare r pictur e o fastronomical activities aroun d Edmonton , I hav e switched t o anactual calendar , wit h meetings , observin g sessions , planetariu mshow premieres , etc. marked for a 3-month period . Eve n i f the nextissue o f Stardust shoul d arriv e late , yo u shoul d stil l hav e th einformation on events for tha t month .

Deadline fo r th e August/Septembe r issu e i s th e Jun e 2 2Observer's Corner meeting .

CLEAR SKIE SAlan Dyer

E

HOURS:8:30am-4:30pm

'• i/-\f- \ i- p

6:30pm - 9:00pmlues - Sun

1:30pm -4:00pmSo" an a Sur ,

Ph.:455-0119

BOOKS FO R THE AMATEUR ASTRONOMER:

The Stars Belong to Everyon e (Hogg)Astronomy with Binoculars (Muirden)Telescopes for Skygazing (Paul)Outer Space Photography (Paul)How To Read The Night Sky (Kals)Edmund Sky Guide1981 RAS C Observer's HandbookBurnhanYs Celestial Handbooks Vol.1 - 3Webb Society Handbooks: Vol.1 Double Stars

Vol.2 NebulaeNorton's Star AtlasSeasonal Star ChartsASTRONOMY magazin e (monthly)

CARLWETZLAR BINOCULARS :

7 power x 50mm8 powe r x 40mm

MEADE 8-inch Schmidt-Cassegrain Telescope:

Special Introductory Price

Basic TelescopePackage (incl . Meade Wedge and Tripod) $'

cli/coucnc/o/tronomy" new/ updat e

MOVING INTO SPACE ?A numbe r o f recen t magazine article s

and new s items have mentioned th e risin ginterest i n space and astronomy among thegeneral public . Thi s is , of course , because o fthe fantastic results o f the Voyage r missionsand the successful flight o f the first SpaceShuttle, Columbia . Al l thi s pays dividends i nincreased suppor t for astronomical researchboth o n Eart h and in space. The SpaceTelescope i s slated to go int o operatio n i nthe mid-1980's , and will enormousl y expan dour horizons . Add to this the existing orbitalobservatories plu s the space astronomyprograms no w in the planning stage s and thefuture of astronomy look s ver y promising .

However, al l this lead s us to anothe rpoint — telescopes ar e not the only thing sabout to go int o orbit . The Solar PowerSatellite (SP S for short ) i s being haile d as theultimate solution t o th e energy crisis . What isan SPS? I t i s a sheet of sola r cell s severalkilometers on a side, locate d i n a 24-hou rorbit abou t 35,000km out. It s function i s toconvert sunligh t into microwave s which arethen beame d back to earth and converted toelectricity.

That's the good part ; what follows are theparts tha t hurt . An SPS will b e BRIGHT. Verybright — so much so that i t ma y even bevisible i n the daytime . Remember Echo I ,Skylab and all the other larg e artificia lobjects i n space? SPS will approac h thebrightness of the moon in the crescentphase. What's more, i f things g o as planned,there won' t b e just on e or two sitting ou t inspace, there ma y be ten o r dozens , or man ymore. I n fact, a recent articl e i n a certainpopular scienc e magazin e enthusiasticall ypredicted a entire bel t of the things encirclingthe earth busily beaming power to an energy-

starved world. Wha t they didn' t mentio n werethe amateur and professiona l astronomersfoaming a t the mout h becaus e they can n olonger se e the sky — only a line o f painfullybright solar power satellite s hanging over theequator, washing out the stars.

These predictions may be in the sameclass as the "airplan e i n every garage" typethat appeare d regularly i n the pulpmagazines i n the 1940' s o r they ma y b e asinevitable as cloud o n a Saturday night, bu t i tis alarming t o consider ou r observin gactivities coming to a final, abrupt end .

Move int o space ? We may hav e to.-- reprinte d from Saskatoon Skies,

newsletter of the Saskatoon Centre, RASC

DIAMONDS ARE FOREVERTiny crystal s of diamond hav e recentl y

been found i n a 10.4-kg iro n meteoritecollected from the Antarctic ice cap in 1977 .The discover y was reported i n Nature b y RoyS. Clarke Jr., Danie l Applebaum, and Daphn eRoss, al l o f the Smithsonian Institution .

This i s only th e second iron-typ emeteorite discovered to hav e diamond swithin it . The other i s the CanyonDiablo meteorit e whic h forme d th e mile-wideBarringer Meteo r Crate r i n norther nArizona some 20,000 years ago. Th ediamonds withi n i t are believed to hav e beenproduced by the shock pressure of impactwhen i t hit the earth. The Antarctic meteorite ,on the other hand , i s much smalle r andwould no t hav e produced sufficien t shockwhen it hit the earth. The diamonds in ittherefore mus t b e the resul t o f some greatcollision that too k plac e within th e asteroi dbelt many million s of years ago .

In mid-Augus t th e Shuttl e wil l agai n b e rolle d out ,ready fo r a September 30 launch. Technicians reportthat Columbia was relatively unscathed by Its maidenflight i n April.

COLUMBIA'S ENCOR EColumbia's secon d flight , no w schedule d

for lat e September, wil l b e a first — the firs ttime a spacecraft has flown twice. Th e Spac eShuttle Columbi a i s now bac k a t CapeCanaveral fo r refurbishing , wit h astronautsDick Engl e and Richard Truly trainin g fo rwhat wil l be their first spaceflight, a 4-daymission.

The payloa d for th e second Shuttl emission i s also being prepared . Calle d OSTA-1 (fo r NASA' s Office of Spac e and Terrestria lApplications whic h i s providing mos t o f th eseven experiments) , the packag e willdemonstrate the Shuttle' s capabilit y a s aplatform fo r scientifi c research . Theexperiments ar e concerned with remot esensing o f lan d resources , atmospheri cphenomena and ocean conditions . Include dare: an imaging rada r devic e to ma p

geological structures for oi l an d gas reserves,an ai r pollutio n measuremen t experimentdesigned to ma p distribution o f carbo nmonoxide i n the atmosphere , and a device tosurvey lightnin g storm s a t night an d durin gthe day .

ANOTHER ON E BITE S TH E DUSTNASA's second "Hig h Energ y Astronom y

Observatory" o r HEAO-2 , ha s ended it smission, it s supply o f contro l ga s exhausted.With 2 9 months o f operatio n t o it s credit ,HEAO-2 performe d mor e than twic e a s longas it s design calle d for , a feat expected t o b eequalled b y HEAO-3 whic h i s still i noperation.

HEAO-2 carrie d th e world's larges tfocusing X-ra y telescope and performe dthousands o f observation s of X-ra y stars,supernova remnants , galaxies and quasars.The forme r Observatory i s expected t o re -enter an d bur n u p in the atmospher esometime i n 1982 .

READYING TH E INFRA-RE D EY EThere ha s been muc h publicit y alread y

surrounding th e Space Telescope schedule dfor Shuttl e launc h later thi s decade . Bu tanother orbitin g astronomica l telescope, onedesigned fo r wor k i n the infra-red spectrum ,is nearing completion , an d wil l b e launche din August , 198 2 via a Delta rocket .

The Infra-Red Astronomica l Satellite, orIRAS, ha s a 60cm mirror , on e capabl e o fdetecting perhap s a million infra-re d sources.It wil l locat e thousands o f ne w quasars,whose ligh t i s 11 to 1 2 billion years ol d an dcomes fro m th e earl y universe . I t will loo kinto th e dust-hidden centr e o f ou r galaxy,detect "invisible " coo l star s nea r the earth ,and i n our ow n sola r system locat e newasteroids an d possible ne w outer planets .Half o f the IRAS' s observing tim e will bedevoted t o a comprehensive infra-re d sk ysurvey an d catalogue.

<i/lioiiomy bo/ic /inhere i / th e moo n tonigh t ?

Most readers of this column wilt be aware ofthe monthly cycle of the moon's phases and thecause o f thos e phases . It's a topic a little to obasic fo r thi s department . Bu t hav e you eve rstopped to figure out the geometry of where themoon i s in the sky at various phases? You mayknow wh y th e moo n i s full; bu t d o yo u kno wwhere to find the full moon? Or the last quarter?Will th e ful l moo n o f summer be at a differentlocation in the sky than the full moon of winter?

Most diagram s illustratin g luna r phasesdepict th e lunar orbi t from a vantage point wellabove the earth's north pole . We see the moonrevolving abou t th e eart h a s som e spac etraveller migh t vie w it . Bu t tr y t o switc h you rvantage point to one on the surface of the earth,

looking out into space. What do we actually seeas the mont h progresses?

At ne w moon , th e moo n and sun are veryclose t o eac h othe r i n th e sky. The y ar e in anearly straight line (only a perfectly straight lineduring a solar eclipse) . As the days go by , theseparation betwee n th e moo n an d su nincreases. A t th e crescen t phase some 3 to 4days after new, the moon is about30° -50° fromthe sun. In which direction? The moon iseasfofthe sun . Eac h day the moo n move s about 13 °further alon g it s orbit ; i t move s counter -clockwise as seen from above the north pole, orfrom west to eas t as seen from earth .

At first quarter, the moon i s 90° away fromthe sun . Two week s after new , the moo n ha s

THIS DIAGRAM SHOWSTHE SKY AS SEEN ATSUNSET ON SEVERALSUCCESSIVE EVENINGSTO SHOW HOW THE MOONTRAVERSES THE SKY ASIT ORBITS THE EARTH.

FIRST QUARTER

€GIBBOUS

> 10 DaysAfter NE W

7 DaysAfter NE W

•^Distance Abov eHorizon i n Degree sIs Moon' s Altitud e

CRESCENT

(3 Day sAfter NE W

90°

RISING FUL L MOO N14 Day s Afte r NE W MOO N

FROM THIS DIAGRAM ONE CAN SEETHAT THE FULL MOON.BEING 180°OPPOSITE THE SUN,RISE S AT SUN-SEI. THE FIRS T QilARJEg MOON,90 EAST OF THE SUN,I S DUESOUTH AT SUNSET,WHILE THE THINCRESCENT MOON APPEAR S LO W INTHE WEST. THE WAXIN G CRESCEN TAND QUARTER MOO N CA N ALSO BESEEN AT MID-DAY EAST OF THE SUN

SETTING SUN

moved onc e agai n int o a nearl y straigh t lin ewith th e eart h an d sun , but thi s time oppositethe sun. I t is now at full phase, 180° from the sunin the sky . Ho w do these angles translat e intowhat w e actually see ?

—The 3 or 4-day old crescent moon is seenin the western sky after sunset, setting perhaps1 to 4 hours afte r the sun.

—The firs t quarte r moo n i s du e sout h a tsunset, and won' t se t until at least 6 hours aftersunset.

—The 10-day old "gibbous" moo n i s in thesouth-east sk y a t sunset and wil l remai n in thesky fo r mos t o f th e night .

—The ful l moon , bein g 180° from the sun,rises i n the east directly opposite the sun as thesun sets . Conversely , the ful l moo n wil l se f asthe sun rises th e nex t day.

—The last quarte r moo n i s also 90° awa yfrom the sun, but to the west. The moon a t thisphase rise s near midnigh t an d i s due sout h asthe sun comes up. The last quarter moon won'tset unti l mid-day .

Got i t so far? Knowin g th e angl e betweenthe moo n an d su n i s enoug h t o giv e yo u a napproximate idea of where to find the moon andwhen t o expec t i t t o se t o r rise . T o b e mor eprecise, however , require s a knowledg e o fwhere the rnoo n i s on the ecliptic.

Most people are familiar with the fact that insummer th e su n i s hig h i n th e sky , while i nwinter the sun traverses the sky at a low altitude.This is due to the tilt of the earth's equator at anangle o f 23.5 ° wit h respec t t o th e plan e o f it sorbit around the sun. The orbit of the moon alsolies in more or les s the same plane as the earth'sorbit. (Actually, the moon can be as much as 5°north or south of the earth's orbital or "ecliptic"plane, bu t this i s not critica l t o ou r discussio nhere.) In short, the moon essentially follows thesame pat h acros s the sky a s does the sun.

But i f th e su n i s high o n the eclipti c (a t adeclination of+23.5° ) as it is at summer solsticetime, where will the full moon be ? Again, it wil l

be 180° opposite the sun. This place s it low onthe eclipti c nea r the sun's winter solstice point(at a declination of about -23.5°). The summerfull moon s ar e alway s ver y lo w i n th e sky,something t o kee p in mind whe n plannin g fo rthe July , 198 2 total eclipse of the moon .

Sum. Solstice. . - . * . . .

NMOON ALWAY S FOUN DNEAR TH E ECLIPTI C I NSTIPPLED ZON E

I Eq .

360°CELESTIALEQUATOR

Just the opposite is true i n winter. The sunis alway s a t a lo w altitude , bu t th e ful l moo nrides hig h int o the winter nigh t sky .

Now think about the first quarter moon for amoment. At verna l equinox tim e around March21, the first quarter moon wil l be 90° east of thesun. Thi s place s i t hig h i n th e sk y nea r th esummer solstic e poin t o n th e ecliptic . Th espring i s a good tim e to photograp h the firs tquarter moo n sinc e i t i s nea r it s maximu maltitude fo r th e year . The sam e applies t o th elast quarter moon in the autumn season, thoughyou'd hav e t o ge t u p earl y i n th e mornin g t ocatch it .

Understanding wh y th e moo n appear swhere i t doe s ca n b e a difficul t concep t t ograsp; i t require s yo u t o translat e word s an d2-dimensional diagram s t o a 3-dimensiona lsky. Bu t onc e yo u hav e th e pictur e straight ,you'll b e wel l o n you r wa y t o understandin ghow the sky works.

~ Alan Dyer

La Sllla In Chile Is home t o a large collection of telescope s operated by the European Souther n Observatory . La Sllla, LasCampanas, an d the Cerro Tololo Inter-American Observator y are the 3 main astronomical site s In Chile. All photos with thisarticle by the author .

The

Southern Skiesof the

Andes

Three observatories are locate d on the pea k o f U s Campanas — a 1-metre and a 2.5-metre telescop e operated by the CarnegieInstitution, an d a .61-metre operated b y the Universit y o f Toronto for Canadian astronomers.

by

Karen Finstad

It take s almos t thre e day s t o trave l fro mToronto t o the U. of T. Southern Observatoryat Las Campanas, Chile. The 16-hourflightto

Santiago has one stopover in Lima, Peru, and sothat i s wher e I firs t se t foo t i n th e souther nhemisphere, on June 7 of last summer. Not thatthere is much to see in the Lima airport at 5 a.m.local time. I spent mos t of the 2 hour wait poringover m y Spanish phras e book .

In those two hour s I had plent y o f time t omemorize many useful phrases ("I do not speakSpanish" and "Wher e i s the washroom? " weremy personal favorites), all of which deserted mecompletely on arrival in Santiago. After a ratherunsettling encounte r wit h a porter , I wa sshepherded safel y to the hote l b y Alan Boyce,U. of T. Resident Astronomer at Las Campanas,and Jose Mazas, a former U. of T. graduate andastronomer a t the Universit y o f Chile .

The followin g da y I ha d tim e t o explor esome of Santiago b y foot before the 6 hour busride nort h t o L a Serena, the closes t cit y t o theobservatory. It is also the location for the off icesand gues t house s o f th e America n Carnegi eFoundation's Southern Observatory . CARSO isthe prinicpl e occupan t o n La s Campanas ,operating tw o larg e telescope s an d a lodge 'there.

Early the next morning w e departed on thefinal leg , anothe r lon g bu t sceni c drive ,paralleling the coast and providing lovel y viewsof th e ocea n befor e turnin g eas t int o highe rcountry.

Access to the observatory i s via a winding,rocky roa d whic h enter s th e Atacam a Deser tand then climbs steeply and dangerously u p theapproximately 210 0 metre s t o th e to p o f La sCampanas. Drivin g throug h th e bare ,multicoloured hill s wit h th e sno w covere dAndes risin g i n th e distanc e wa s particularl ystriking. Th e man y colour s (pinks , greens ,violets and yellows) in the surrounding hill s wasdue no t t o vegetatio n bu t t o th e abundan t

variety o f mineral s i n the rocks .The thre e dome s o f th e observator y ar e

spread i n a row acros s the hummock y summi tof the "mountain" . Th e smallest dome i s the U.of T.' s .61-metre (24"), whil e th e large r dome shouse th e 1-metr e (40" ) an d th e 2.5-metr e{100") CARS O telescopes . Als o o n th emountain i s th e comfortabl e CARS O lodge ,containing livin g an d eatin g spac e fo r th eastronomers an d maintenanc e people . Th eUn i ve r s i t y o f To ron t o ha s i t s ow naccommodation, know n a s Cas a Canadiense,not fa r from ou r dome .

The Canadia n telescop e i s a 61cm Ealin gwhich, accordin g t o the extensive diaries kep tat Casa Canadiense for the last 7 years, was thesource o f man y headache s i n th e earl y years.However, everything ran perfectly smoothly fo rme, a t leas t mechanically . Th e weathe r wa sanother matter .

The seeing conditions during m y first nighton the mountain rule d out photometry , bu t thesky wa s clea r enoug h fo r som e sigh t seeing.And quite spectacular sights they were, too, forfrom the latitude of-29° the bright star clouds ofthe Galacti c centr e ar e almos t directl yoverhead a t tha t tim e o f year . Th e Larg e an dSmall Magellani c Clouds , the Southern Cross ,a and /3Centauri,Scorpius, the Coalsack.the (}Cen an d ''1 Carin a clusters , Jupiter , Mars ,Saturn; eve n th e zodiaca l ligh t an d a fe w

noctilucent cloud s were al l visible that night .This regio n i s on e o f th e world' s bes t

astronomical sites ; th e dr y ai r an d climat eprovide marvelously clear and steady seeing —most o f th e time , tha t is . Naturally , I arrive dthere i n the middl e o f th e worst winter anyonehad eve r seen . I t actuall y raine d 2 o r 3 timesduring m y run , whic h i s quite unhear d of .

In between the fog and the clouds I had lessthan a handfu l o f photometri c nights , an d a smany agai n whic h wer e sui tabl e fo rspectroscopic observations . Needless t o say ,my photometri c progra m o f Cephei d variabl eobservations barel y go t of f th e ground . Bu tevery cloud, i f you'll forgive the cliche, brings asilver lining , o r a t leas t a golden sunset , and Idid se e some grea t ones . An d o n the clearestdays whe n th e atmospher e wa s ver y steady,sunset on the sharp horizon line of the ocean 80km away provided perfec t conditions for seeingthe Gree n Flash .

This i s a rare atmospheric effect caused byrefraction o f th e sun' s imag e int o severa loverlapping images of different colours with thegreen imag e o n top . (Th e blu e wavelengthshave been scattered by atmospheric particles. )At th e las t instan t befor e th e su n set scompletely belo w th e horizon , th e uppermos tgreen ri m become s visible for a few seconds . I *was able to see the Green Flash on hal f a dozenoccasions, bu t i t i s a difficul t effec t t o

Casa Canadiens e Is the smal lresidence building for Canadianastronomers usin g the.61-metre U . of T. telescop eat La s Campanas.

10

The exterio r o f th e 3.6-metr e telescop e a t th eEuropean Southern Observator y a t La Sflla , Chile.

The 3.6-metr e ES O reflector , a n Impressiv etelescope use d b y a consortium o f 1 0 nations.

photograph, and al l o f m y attempts failed.During m y 3 wee k observin g run , a

succession o f astronomer s using th e CARSOtelescopes came and went. The 1-metre is usedvery often for infra-red observations and was allbut burie d i n cryogeni c coolin g equipmen twhen I saw it. The 2.5-metre Dupont telescopeis a beautifu l instrument , an d it s optic s an dmechanical desig n ar e amon g th e bes tanywhere. I was shown a contact prin t mad efrom on e o f th e hug e photographi c plate s(about 5 0 c m square , f think ) take n wit h thi stelescope which had undistorted stellar imagesalmost to th e very edge of the plate .

Practically "next door" to Las Campanas isthe saddl e shape d pea k o f L a Silla, site of th eEuropean Souther n Observatory . It s larges tdome, housing the 3.6-metre, is just visible as awhite spec k fro m Campanas . One afternoon Idrove ove r wit h anothe r visitin g graduat estudent, Mathe w Malka n fro m Caltech .

Operated jointl y b y abou t 1 0 Europea ncountries, ES O i s a mos t impressiv e place .There i s a smal l villag e a t th e bas e o f th emountain fo r maintenanc e crews, and anotherat the top for visiting astronomers and residentscient ists an d technicians . Th e optica lcollection includes , besides the 3.6-metre, two1.5-metre telescopes, 8 or 9 smaller telescopesof various sizes and purposes, and one contactlens, which I managed to los e during th e tour.

The Universit y of Toronto's observator y inChile i s unquestionabl y a valuabl e an dproductive researc h instrument . However , theUniversity i s no w strugglin g t o kee p u p th eoperation i n th e fac e of drasticall y increasin gcosts. I t i s to b e hoped tha t the facilit y wil l beavailable t o Canadia n astronomer s fo r a longtime t o come , an d tha t othe r student s lik emyself wil l continu e t o b e offere d th eopportunity t o wor k there . Bu t I wis h the mbetter luc k wit h the weather.

11

Radioflstronomu

for th e

flmateurbyDave Beale

L et's take a look at the prospects for amateurobservations in the radio spectrum. To besuccessful i n jus t detecting objects , th e

amateur must :1. construct o r bu y relativel y large antennas2. construct o r bu y ver y sensitiv e electronics3. operate the abov e i n isolated areas.

The majorit y o f radi o object s hav e signalstrengths o f only a few "Janskys" (1 Jansky =10-24 w/m2/Hz). I f a 10 metre diameter parabolicreflector i s constructed t o operate at 150 MHz,we coul d expec t t o receiv e fro m a n averag ecelestial source, 10~16 Watts. Ordinary receiverswouldn't notic e this low signal level , since theyhave typical "nois e floors" of about 1O' 15 Watts.The objects observabl e b y amateur equipmen tare listed in the Observer's Handbook.

These are the mos t powerfu l objects . Fo rthe deep-sk y source s on the list , the amateu rshould b e well-verse d i n radi o electronics ,antenna fundamentals, and should be willing tospend amount s o f money equivalen t t o buyin goptical equipment. I f you are interested i n thisarea i t ca n b e ver y rewardin g (jus t t o detec tsomething ! ) since i t i s a field of investigatio nrarely attempted by amateurs. Little or no usefulwork assistin g professional s ca n be seen her e

IS

for now , however.Equipment ma y be purchased (see Sky and

Telescope fo r sources ) or can be found on thesurplus market s an d modified . Du e t o th especialized needs, however, the best route is tobuild everything yourself. The most promisingmethods for amateurs is to operate below about5 GH z (500 0 MHz ) usin g th e bes t affordableconverter an d a n inexpensiv e commercia lreceiver modified fo r bandwidth and detection.The converte r would contai n a very expensiv eRF amplifier (abou t $500 for parts ) followed bya loca l oscillator , probably crysta l controlled,and multiplie d u p t o th e require d frequency.The goa l i s t o conver t th e receive d signal t osome lowe r frequenc y tha t i s no t normall yoccupied b y a stron g transmitter , bu t i saccessible wit h a commercia l receiver . I t i spossible t o coo l th e converter ; however greatc a r e m u s t b e t a k e n du e t o th eexpansioncontraction effects , eve n insid ecomponents. I t mus t b e emphasize d tha t th emajor portion of the project's expense and workwill be involved here.

The antenn a can , o n th e othe r hand , b econstructed fro m scratc h an d eve n a ninterferometer can b e easily built (se e Sky andTelescope 1978-79) . The output of the receivermay b e listene d to , measure d and manuall yrecorded, o r connecte d t o a strip-char trecorded. But , the antennas are the most fun tocontruct, sinc e ther e i s no t s o muc hengineering required. I recommend a parabolicdish fixed on the ground with only the elevationadjustable, lettin g th e Earth' s rotatio n swee pthe sk y i n azimuth . I t shoul d b e a s bi g a spossible t o giv e you r electronic s a fightin gchance, bu t b e carefu l t o kee p i t reasonabl yrigid. Accuracy o f 1/8t h wavelengt h would b efine (1cm at 2700 MHz). The dipole pickup mustbe more accurately positoned a t the focal pointof the dish (±1/10 wavelength or better) and canbe accomplished whil e monitorin g th e output.What you will endupwithisan increase in staticwhen observin g mos t objects , bu t eve n thi sresult ca n b e quite satisfying fo r th e die-hardradio astronom y fan .

For those wanting to do potentially "useful"work, ther e ar e at leas t two possibilities . Theabove electronics ma y be constructed a t lowercost with less sensitivity an d used with a smallerdish tracking the sun in a "solar patrol" mode to

warn o r lear n o f sola r flare s an d long-ter mcycles. Th e frequenc y ma y b e chose n afte rcareful consideration of the literature. It may bemore usefu l to pick a frequency not monitore dby others.

The secon d projec t involve s a n are a w especialize i n — aurorae . I n the October , 198 0issue of the Journal o f the R.A.S.C. Colin Keaypublished a n articl e title d "Audibl e Sound sExcited b y Aurorae and Meteor Fireballs." Themechanism of this phenomena is not a t presentwell understoo d an d i s stil l controversial .However i t involve s th e "crackling " o r hissin gsounds heard sometimes during brightfireballsor spectacular auroral displays. Keay propose s

VIRGO A

antenna i s directiona l alon g th e plan e o f th eloop. Wit h thi s setup , whistlers , th e "daw nchorus", an d other natural phenomen a ma y bedetected. Th e earth' s ionospher e act s a s ashield, however , so no extra-terrestrial sourceswill b e heard . Everythin g hear d come s fro mbelow the ionosphere .

Because this equipment i s so simple, small,and powe r efficient , i t i s actuall y a portabl eradio telescope . Also, the natura l phenomenaheard ca n b e quit e beautifu l an d interesting ,certainly mor e audibl y uniqu e tha n mer e hissand static . Th e whistler s ar e though t t o b ecaused b y lightnin g radi o energ y bouncin gback an d fort h betwee n th e eart h an d

f = 238.5 MH zJan. 30 , 198 1

The tracing wa s acquired by amateur astronomers of the Ottawa Centre of the RASC using their interferomete rInstallation at their Indian River Observatory Site. It records th e powerful radio source Virgo A, known to opticalastronomers as the galaxy M87. Reprinte d from AstroNotes, the newsletter of the Ottawa Centre, RASC .

that the "sounds" are generated by radio energyin th e VL F o r Ver y Lo w Frequenc y spectrum ,particularly aroun d a frequenc y o f 8 KH z —audio frequenc y radio waves ! A receiver at thisfrequency become s ver y eas y t o construct ,consisting o f a filte r ( to remov e 60 H z powerline hu m an d a cut-of f uppe r bandwidt h t oabout 1 2 KHz), followe d b y a high gain audi oamplifier feedin g a detector an d speaker. Thedetector woul d b e connecte d t o a char trecorder o r mete r fo r recordin g data , th espeaker merel y fo r monitoring .

The antenn a fo r suc h a device woul d b erather unique. A conventional half-wav e dipolewould b e almost 19k m long! Instead, we take alarge diamete r (1/ 2 inc h o r so) conductor an dmake a n 8 to 2 0 turn loop , abou t 1 metre i ndiameter. Th e conducto r ma y b e hollo w bu tshould b e very conductive. Aluminu m ca n b eused bu t coppe r i s better . Th e output ma y betaken fro m th e tw o end s o f th e loop . Thi s

ionosphere. The dawn chorus, as I understandit, is a plasma event generated in the ionosphereby the change s induced b y sunlight strikin g it .Both thes e phenomen a wer e recorde d a tJupiter an d Saturn b y the Voyager spacecraft.With luck , th e hissin g an d cracklin g o f th eaurorae an d o f bolide s ma y als o b e detected ."Listening" fo r meteor s woul d b e bes tundertaken i n conjunctio n wit h naked-ey emeteor-watch patrols .

In conclusion , whil e radi o astronom yrequires knowledg e i n fields othe r tha n thos enormally persue d b y amateu r telescop emakers, an d requires operating at the limits ofdetection ability , th e reward s ca n b e jus t a sgreat a s in optica l astronom y — and for now ,more unique. Observing can be done wheneverit is convenient; you don't have to be a nightowlor dependen t o n th e weather , almos t reaso nenough t o take up radio astronomy !

Good observing .

13

Consi

Two historic astrographs have seen agreat deal of use :ABOVE is the Metcai f 40-cmastrograph a t the HarvardObservatory's old Agassl z Station .AT LEFT Is the double astrograph o fLick Observatory . It s twin 50-cmlenses are used to take simultaneousphotos I n two colours.

14

ructing anAstrograph

byDave Belcher

I t ha s bee n th e drea m o f man y amateu rastronomers t o emulat e th e photographi cwork o f the world's grea t observatories such

as Palomar, Lick, and Kit t Peak. It would appearthat many of these amateurs are now producin gphotographs tha t indee d begi n t o riva l thos etaken b y th e gian t telescopes , as witness th eworks o f Be n Mayer , Everei d Kreimer , an dCanada's own Jac k Newton .

These not-so-amateu r amateur s ar ecombining today' s fas t colou r emulsion s wit hthe mos t exoti c technique s t o obtai nmagnificent photograph s o f al l th e Messie robjects and many of the N.G.C. objects, targetsonce thought of as next to impossible t o recor din shor t exposure s wit h amateu r telescopes .

However, mos t o f thos e telescope sproduce thei r image s on a piece of film that isonly 24 by 36 millimetres (35m m film), which inmost cases represents an area of the sky of 1 ° orless. I n orde r t o cove r eve n th e norther ncelestial hemispher e a t thi s rate , i t woul drequi re mor e tha n 20,00 0 separat e

photographs. Wouldn' t i t be nice to cover, say,one hundre d squar e degree s o f th e sk y o n asingle exposure with an image scale of 1 ° perinch, using a telescope of onl y eigh t inche s i naperture? Enter , the astrographic camera.

The astrographi c telescope-camer arepresents a n importan t researc h tool , fo r i tenables the professiona l astronome r t o obtai nphotographs o f larg e area s o f th e sky , evenlarger tha n thos e obtaine d wit h Schmid tcameras. Fro m these large plate s h e can sca nthe image for objects that can be photographe din greate r detai l an d large r scal e wit h th e bi gtelescopes.

Most o f th e majo r observatorie s hav eastrographic telescope s fo r makin g broa d sk ysearches. Th e mos t famou s i s th e Carnegi edouble astrograp h a t Lic k Observatory . I tconsists of two 50c m diameter lenses mounte din tandem . On e camer a i s loade d wit hredsensitive emulsion , th e othe r wit hbluesensitive. Simultaneou s exposure s o f th esame are a o f th e sk y ca n the n b e obtained a tdifferent wavelengths and then compared. Th eCarnegie astrograp h i s on e o f th e world' sgreatest galax y hunter s an d i s als o use d t odetermine th e prope r motion s o f stars . Othe rnotable astrograph s includ e th e 33c m Lowel lastrograph a t Flagstaff , Arizon a (o n whos e

11

Elements o f a n Astrograp h

EASTMAN KODA K LEN S AS -SEMBLY, f/6.3 , 48" f.I. This was used withthe K-40 aerial camera, which takes a 9" x 18"plate. Approximate dimensions: 14" diameterx 26" long. Contain s iris . Lense s mounte d inaluminum housing . Approximate weigh t o funit - 12 5 Ibs.

The astroqraphi c camer a Dav e Belche r i sbuilding wil l us e th e len s advert ise d abov eJust .i s importan t a s th e optic s i s th e mount ,and Dav e ha s chose n th e massiv e for k moun tfrom Astf O Work s depicte d belo w Tha t i snot Dav e standin g besid e i t

II

plates Pluto was discovered i n 1930) , the 60cmBruce telescop e use d i n Sout h Afric a b yHarvard Observator y t o sca n th e souther nskies, an d th e Metcal f 40c m double t a tHarvard's Agassi z station.

Any camera , onc e i t i s pointed t o th e sky,becomes a n astrograph . However, i n orde r t oobtain large scale photographs on large plates ,the camer a require s a bi g len s wit h grea tcovering powe r and a flat field. Process lenseswhich ar e pe r fec t l y co lour -cor rec ted ,extremely sharp and ca n cove r plate s as largeas on e mete r squar e wit h a foca l lengt h o f1800mm would b e ideal, except for one seriousdrawback — they ar e very slow, usuall y f/ 9 t of/16. Hence , th e aeria l camera lens .

The astrograp h whic h I a m presentl yconstructing wil l emplo y a ver y larg e len ssystem use d i n th e K-4 0 aeria l camera .Manufactured b y Eastma n Kodak, the lens hasa foca l lengt h o f 48 " o r 1220mm , ha s a neffective aperture o f f/6.3 and can cover a plateof 9 by 1 8 inches. Th e len s weighs in at a hefty125 pounds, and i s available as a surplus itemfrom C & H Sales in Pasadena for less than $500.

Holding an d guidin g thi s muc h mas srequires a very sturdy mount . To this end I haveopted for the 30cm (1 2 1/2") Astro-Work s forkmount. Suspende d betwee n the fork s will be acradle structur e fo r th e gian t len s plu s aplatform abov e fo r othe r cameras . Mounte dbeside th e bi g len s will b e the Questa r 7 barrelassembly which wil l b e used for guiding .

Initially, I would lik e to use the astrographto compile a large scale photographic sk y atlason plate s o f 8 b y 1 0 inches , givin g a fiel d o fabout 7° by 9° on each. This project is expectedto take 3 to 4 years. In addition, m y sky-searchprogram wil l includ e come t hunting , asteroi dphotography, an d galax y searches , as wel l aswhat I hope will be some excel lent photograph sof th e Milk y Way .

Not t o b e outdon e b y th e Edmonto nCentre's ow n 45c m Dobsonia n telescope , Iwould lik e t o emplo y th e len s as a Super Ric hField Telescope , usin g a giant Ploss l eyepieceof 55m m foca l length . Wit h a magnification o f22.5x an d a fiel d o f vie w o f 2.75° , i t shoul dprovide views of the heavens that are absolutelyentrancing. Completio n i s schedule d fo r lat ethis summer . I can hardly wait .

1t

ici/c new /

Two view s o f STARNIGH T '81 , a cloud y bu t stil lcrowded event.

'•6 OUT OF 8 ISN'T BAD

Starnight '8 1 over the weeken d of Ma y 8and 9 was a bit o f a washout this year , wit hclouds bot h night s preventin g an y observing.Nevertheless, 700 people turned out , viewedthe RAS C and QEP exhibitsand looked a t the few telescopes that wereavailable. One can say i t was a qualifiedsuccess. Thi s i s only th e second tim e i n the 8Starnights hel d since 1974 that the even t hasbeen clouded out, a n excellent record .

We thank everyon e who assiste d wit hthis year's Starnight , bot h from th e ranks of the

Planetarium and from the Edmonto n Centre.Your effort s wer e no t i n vain!

THE 2nd ANNUAL RAS C AWARDSOn Saturday , March 21, the Edmonto n

Centre held its annual Banque t and award snight. A n excellen t talk o n 'Quasars , Sputniksand the Continenta l Drift' was presented byDr. Edo Nylan d o f the U . of A .

Ted Cadien, presente d th e Centre' sseries o f award s in recognition o f meritoriousachievement during th e previous year.

The awards were as follows:ASTRO—PHOTOGRAPHER O F THE YEAR :Dave 6ea/e,for his excellent results inpiggyback an d prime focus deep skyphotography.OBSERVER O F THE YEAR :Andrew Lowe, for hi s continuing progra m ofdeep sky andoccultation observing, includin g hismarvelous work i n computer analysi s ofeclipses, occultation an d planetary position .ANGUS SMIT H A W A R D (TELESCOP EMAKING):Mark Leenders, fo r hi sconstruction of a 15 cm (6" ) f/1 0 refractor.PRESIDENT'S AWARD:Alan Dyer, forservice to the Centre as editor o f Stardust,and in hi s other officia l positions with theCentre over the pas t few years .

UPDATE O N BUCKAfter lookin g a t all the various

possibilities, th e group working on the BuckMountain sit e development ha s concludedthat a n ATCO-style trailer uni t woul d b e themost suitable structur e for Buc k as theCentre's observing hut . Th e cos t o f a usedtrailer i n the 10 x 25 ' range , includin gtransportation costs , i s within ou r budget .This saves us the wor k o f building a structure

17

from scratch , though som e interio r wor k ma ystill b e needed , plu s th e preparatio n o f asuitable pa d area.

THE HOWEL L DONATIO NJohn Howell , a member o f the Calgar y

Centre, who ha s been livin g i n the Breto narea fo r th e pas t few years (nea r Buc k Mtn.) ,has expressed the desir e to donat e a nobservatory dom e an d massiv e fork moun tfor a 40 cm telescope t o th e Centre . Thes ewere a t John's acreag e near Breton , bu t amove to th e wes t coas t has forced hi m t odispose o f these items . A s o f thi s writing ,Centre member s hav e no t see n the dom e an dmount, bu t wil l likel y gladl y accep t thedonations fo r possibl e futur e us e at Buck .

THE MA Y MEETIN GOnce again , we were unabl e t o hea r fro m

Dr. Phi l Curry a t our Ma y Genera l Meeting ,as Dr . Curry wa s called out o f tow nunexpectedly. W e thank Joh n Hault , Projec tManager fo r th e Edmonto n Spac e SciencesCentre fo r steppin g i n a t the las t minut e wit han excellen t talk o n the ne w planetariu mfacility.

The las t Genera l Meetin g fo r th e curren tseason wil l b e Monday, Jun e 8 , although th emonthly Observer' s Corners wil l continu ethrough July an d August.

The nex t issu e o f Stardust fo r Aug./Sept .will contai n mor e informatio n o n RASCevents i n lat e summer an d earl y fall .

OTICE o f GENERA L MEETING S

MONDAY, JUNE 8Dr. Chris Pritchard , U. of C."The Canada France Hawaii Telescope"Dr. Pritchard Is wMi the University of CalgaryPhysics Dept. and his area of research Is galaxiesand cosmology. Dr. Pritchard will talk on hisexperiences observing wrdi the 3.6-metr e CFHtelescope on Maun* Kea In Hawaii. We've heardtalks on how the telescope was constructed, nowwell hear more about what It Is like to actuallyuse It. Dr. Pritchard Is our annual exchangespeaker from the Calgary Centre.

MONDAY, SEPTEMBER 1 4topic to be announced

Deadlne for the Aug./Sept. Issue of Stardust IsMonday, Jun e 22 .

Both meeting s at :8:00 PM ; MUSI C ROOM , EDMONTO N PUBLI C LIBRAR YGuests an d member s o f th e publi c ar e welcom e

11

'

the fourth annualsummer solsticeCELEBRATION

TO GET T O BUCK:

TRAVEL WES T O N HWV 3 9THROUGH CALMAR ,THORSBV & WARBURG . TUR NSOUTH (LEFT ) ONT O HWY 1 2AT ALSIKE. TRAVEL T OBRETON. JUS T SOUT H O FBRETON, TUR N WES T(RIGHT) ONT O PROV .5ECONDARV ROA D 616 (BUC KCGEEKC9AD}. TRAVE L!7.5KM (HMD. TURN SOUTH(LEFT), 60 5.9KM (3. 7 Ml.)TO TH E ENTRANC E ROA D TOSITE O N TH E EAST SID E O FTHE MOUNTAIN. DRIV E IN ONTHE DIRT ROAD .

fit Buc k mountain, Saturday* June 20 starting at 9:oopm

EVERVONE I S INVITE D TO THIS ANNUAL EVENIN G OF MERRIMENT.BRING VOU R OW N FOOD AND REFRESHMENTS. THER E WILL BE LOTS OF WOO D FOR THE

CAMPFIRE. FO R MORE INFORMATION , PLEASE PHONE TED CADIEN AT OR. MAP S WILL B E AVAILABLE AT THE JUNE GENERA L MEETING.

10

* A WEEkEN d o f dEEp'sk y obsERviNq AT AN AlmudE of OVE R 8000 fEET , WIT H MEMBERS of THE ECJMONTO N ANdCENTRES AN d of TH E McdiciN E HA T Club I N

* B E pREpAREd fo R A WEEkENd o f SElf'SuffiCJEN T pRJMITJVE CAMpJNq UNdER VERy dARk fklES. IT CAN qET QUJTE

COOl A T NJqH T A S WEll!

it FO R MOR E JNfORMANON , O R foR dJRECTIONS , plEAS E pHON E DAV E BEA U AT . MApS SHOUld

AVAJUbU A T ThE O.C . MEETJNq S pRJO R T O Th

at th e planetarium

Our curren t featur e production Death o fthe Dinosaurs continue s it s popular ru n unti lSunday, June 14 . Beginning Tuesday , June16 at 8:00 pm and runnin g unti l the Labou rDay weekend in September, will b e ourperennial summer classic, Summer Starlight.This progra m i s a live lecture on th e stars ,constellations and features of the summersky. However , this sho w is our secondaryprogram fo r the summer. Beginning Friday ,June 2 6 at 8:00 pm i s our ne w majo r feature,A Galaxy o f One. This wil l run throughou tthe summe r month s a t 3 pm and 8 pm everyday {including holidays) , with SummerStarlight revertin g to a 9 pm slot .

A Galaxy o f On e has been written fo r u sby Pau l Deans , now of the MclaughlinPlanetarium staf f i n Toronto. Th e progra mlooks a t the possibilit y o f extra-terrestria l life.Same old stuff, you say ? Not so , because thisshow take s the stand that lif e elsewhere inthe galax y may not b e so abundant afte r all .Although th e question i s by n o mean ssettled, some ne w research ha s suggestedthat the developmen t o f life on earth mayhave been a more uniqu e occurenc e tha npreviously assumed . While we are not out t oconvince anyone of an y given theory, we areattempting to give equa l time to the 'anti-Sagan' point o f view . Despite what Car l says,there ma y not b e 'billions upo n billions ' o fcivilizations ou t there !

The Planetarium's community astronomyprograms hav e also been goin g stron g lately.From Januar y 1 to Apri l 30 , a total o f 420people hav e attended one or mor e ofStewart's astronom y courses, seminars , o rspecial talks. Durin g th e las t week of April , aseries o f noon-hou r 'brow n bag ' astronomytalks was presented, with abou t 2 5 peopleattending each lecture . Oddly enough, the

'straight' talks on Voyage r and the Shuttlewere mor e popular than the talks on pseudo -science topics lik e UFO' s and the Jupite rEffect.

Starting Tuesday , June 1 6 for 3consecutive Tuesday's , Stew wil l b e runninga Telescope User's Course at the AC TRecreation Centre , Contac t th e Planetariumfor mor e information .

For one week every mont h durin g July ,August, September, and October , we'll beorganizing public observin g session s at thePlanetarium. Thes e will ru n on each of th efollowing nights :

Tuesday, July 6 to Monday , Jul y 12Tuesday, Augus t 3 to Monda y Augus t 1 0Tuesday, Sept . 1 to Monday , Sept . 7Tuesday, Oct . 6 to Monda y Oct . 1 2

As with las t summer's sessions, we'l l b easking fo r voluntee r hel p fro m RASCmembers to hel p ma n telescopes, and toperhaps se t up their ow n scopes . Again ,contact Ste w at the Planetariu m a t 455-0119 .

There hav e been a number o f staffadditions an d changes lately . Garth Fitzne rand Jane Micke y hav e been hire d as part -time lecturers , Jane Harric k i s our ne wtypesetter an d librarian, while Ric k Corrigan ,planetarium artis t (wh o lef t to atten d a filmanimation schoo l i n Toronto), has beenreplaced by Sharon Dunnigan . I n addition ,Ted Coldwell, planetarium photographe rsince 1975 , will b e departing fo r Nov a Scotiain July; his replacemen t ha s yet to b e named.

The desig n o f the Space Science Centr eis progressing very well. The Zeiss Jena sta rprojector ha s been ordered ; we hope t o havemore-details o f the Centre' s progress i n thenext issu e of Stardust, includin g somearchitectural drawings of the revised design .

21

WINNIPEG CENTR E

MASCOIN 1981MANITOBA ASTRONOMICA L CONVENTION .

RIDING MOUNTAI N NATIONA L PARK .FRIDAY, JUL Y 3 1 t o MONDAY , AUGUS T 3

For mor e informatio n concernin g th e programme , accommodation .fees. etc. . write t o Gu y Westcott . c o Winnipe g Centre . P.O. Box174. St . Jame s P.O. . Winnipeg. Manitoba . R3 J 3R 4(Phone 204-269-149 9 afte r 6 pm )

look boc k lim e

•

JUNE, 1931 :"Astr. Jour., No. 957 contains articles by P.

van d e Kam p o n th e distanc e o f th e galacti ccentre an d th e thicknes s o f th e galacti cabsorbing layer . The thicknes s o f th e laye r i sgiven a s 210 parsecs, with a probable erro r o f40. The distanc e of the centr e of th e galax y isfound fro m (1 ) th e centr e o f th e syste m o fglobulars clusters , (2) fro m a study o f clustertype variables in a Milky Way field, (3) from theconstants o f galacti c rotation . Th e extrem evalues o f the distance o f the centre in parsecsare 16,70 0 and 7,000 . H e suggests 12,000 as amean (sa y 40,000 light years). "

JULY, 1931 :"Mr. K . Hirayama, o f Toky o Observatory ,

investigates i n Proc . Imperial Acad. Japan theeffects o f th e impact o f a star with a sphericalnebula. Th e relativ e velocit y i s probabl yhyperbolic befor e impact, but it may be reducedby the impac t belo w paraboli c value , in whichcase there wil l be repeated impacts , which wil lresult i n the captur e b y the sta r of par t o f thematter o f th e nebula , whil e th e star' s orbi trelatively to the nebul a will be reduced in size.The autho r suggest s tha t th e nebul a migh t i ntime b e so reduced an d broken u p as to form asystem of planets revolving around the star; this

is an alternative to the theory tha t explains theformation of planets by the tidal action of a starpassing nea r the sun. "

JUNE, 1881 :"To th e studen t o f scienc e wh o

contemplates th e su n b y da y o r th e star s b ynight tw o question s wil l inevitabl y occur . Thefirst wil l hav e referenc e t o th e sourc e fro mwhich thos e vast s orb s hav e derive d thei rstupendous stor e o f high-clas s energy ; th esecond to the astonishing regularit y with whichthey are able to give it out. We ask then, i n thefirst place , fro m wha t sourc e ha s thi sinconceivably vas t stor e o f energ y bee nderived? Th e onl y hypothesi s ye t though t o fthat can account for it is that which first occuredto Maye r an d Waterson... . Accordin g t o thi shypothesis w e ma y imagin e th e particles o fmatter, when originally produced, to have beenat a great distanc e fro m eac h other . As thes eparticles graduall y came togethe r in virtue oftheir mutua l attraction , hea t woul d b egenerated i n the condensin g mass , and i t hasbeen calculated tha t this cause, by storing up avast amoun t o f hea t i n the sun, i s sufficient t oaccount fo r it s wonderfu l outpourin g o f hea tand ligh t throughout a long series of ages. "

-- complied by Tony Whyte

TorFOR SALE : 20c m (8" ) f/ 6 Mead e mirror ,

1.83" secondary mirror, fiberglastube, plus6x30 finderscope and homemad e woodenmirror cei l for above mirror. All less than 1year old . $130 . Phon e Dir k Auge r a t

NOTICE — STOLEN TELESCOPE :The Quee n Elizabet h Planetariu m wa s

recently broke n into . Stole n wa s 1 Edmund 6 "(15cm) f/6 equatorial Newtonian telescope on apedestal mount. Any information regarding thisunit wil l b e appreciated. Phon e Stew Krysko atthe Planetariu m a t 452-9100.

23

The distinctive "teapot" shape of Sagittarius stands out amid the rich star clouds of the Milky Way. Unfortunately, this area of thisky just clears the southern horizon from our latitude and Is not well seen. This photograph was taken from the 4000-foot level oMt. Hopkins , sit e of the Multiple Mirro r Telescope , nea r Tucson, Arizona. I t Is a 20-mlnute exposure at f/2 o n Fuflchrome 40C

— photo by Alan_py e

24

upogittariu/

Sagittarius lies in the direction of the centre of our galaxy. Within this wide expanseof th e Milky Way are some of the brightest star clusters and nebulae in the entiresky. From our northern latitude a very clear dark sky and an unobstructed southern

horizon Is needed to observe any o f this month's objects well.

** CLASS I OBJECTS **Bright, easy to find

MB, the Lagoon Nebula is one o f the finestnebulae in the sky . It i s located northwest of ASagittarius whic h mark s the tip of the 'tea pot'.From a dark site, it appears as a fuzzy patch tothe unaide d eye , and i s revealed as a glowin gexpanse o f ga s i n a pai r o f binoculars . I n anamateur telescope it appears as a fine irregularnebulosity surroundin g th e open cluster NG C6530. The tota l diamete r of th e Lagoo n i s over1/2° s o a low power eyepiece is needed to see itwell. Th e nebul a i s cu t almos t i n hal f b y aprominent dus t channe l abou t 2 ' i n width .Although i t i s a frequently studie d object, thedistance t o M 8 i s stil l relativel y uncertain .Estimates have range d from 3000 to 5150 lightyears. I f we assume it is about 5000 light yearsaway, then its size works ou t to at least 60 x 44light years.

About 1.5 ° t o th e northwes t i s anothe rbright nebulou s patc h calle d M2 0 th e Trifl dNebula. I t has been suggested that M20 is partof th e sam e vast syste m o f nebulosit y a s M8 .The Trifid consist s o f a large bright nebulou spatch divided into three irregular areas by threedistinct dar k lanes . These dark spokes appearto radiate from a bright triple star HD 40. Thesedark lanes are visible in a 15 - 20 cm scope. Thefull exten t o f thi s nebul a i s abou t 25 ' i ndiameter. A s wit h M20 , this distanc e t o M 8 isuncertain, wit h estimate s rangin g fro m 174 0light years to 6060 .

** CLASS II OBJECTS **Fainter, but distinctive

Class I I start s ou t wit h a pair o f globula rclusters NG C 652 2 an d 6528 . The y ar ereasonably easy to locate, as they are located inthe sam e fiel d a s y Sagittarius . The y ar emagnitudes 10. 5 and 11 respectively, and bothare compose d o f star s o f aroun d 16t h mag .They'll be pretty close to the horizon.

NGC 6645 is a fairly large, rich open clusterlocated just south o f the constellation Scutum .More precisely , it s about hal f way between 7Scuti and M25. It is about 10 ' in diameter and ismade up of abou t 7 5 stars.

** CLASS III OBJECTS **Challenge objects

Class II I thi s mont h i s occupie d b y on eobject, NG C 6822 . Thi s large , faint , irregula rgalaxy i s a member of the 'Loca l Group'. I t issituated i n the northeas t corne r o f Sagittariusand i s located in the same field of vie w as theplanetary nebul a NGC 6818. This planetary is avery bright bluish object and is easily seen, butnearby 682 2 i s very difficult . I t i s calle dBarnard's Galaxy , afte r it s discovere r E . E .Barnard. The object i s very large and diffuse; itrequires lo w power, preferabl y wit h a rich-fieldtelescope. No one has yet seen it from Buck, butDave Belche r report s sightin g i t fro m Platea uMountain and Darrel l Cross has spotted i t fromMount Hopkin s nea r Tuscon, Arizona.

Constellation Chart courtesy ofHubbard Press

DEEP-SKY OBJECT S

OBJECT TYP E MAG .

Class I

M8,M20

Class II

ENE/RN

NGC 6528/6522 G C 11/10. 5NGC 664 5 O C 9

Class III

NGC 6822 G-Ir r 1 1Barnard's Galaxy

Open Cluster....Globular Cluster.- Emission NebulaReflection Nebula

G- Galaxy + Hubble type

the /olo r /y/te mTHE SUN: The sun reaches its summer solsticepoint a t 5:45 am MDT o n the mornin g o f Jun e21. Eart h i s a t it s furthes t poin t fro m th e su n(aphelion) on July 3 . On July 31 there will b e atotal eclipse of the sun as seen from Siberia andthe Pacifi c Ocean. This wil l b e seen as a slightpartial eclipse in the North-West Territories andextreme northern B.C. and Alberta. (Now wheredid I put that piec e o f welder's glass?)

THE MOON : A partia l luna r eclips e wil l b evisible from our part of the world on the night ofJuly 16-17 . At mid-eclipse, 55% of the moon'sdisk wil l b e in the earth's umbra l shadow. Thi swill produc e a noticeabl e "bite " ou t o f th e

otherwise brilliant dis k of the full moon, but noreddening o f th e shade d portio n wil l likel y bevisible. Umbral eclipse begins at 9:25 pm MDT,July 16 , and ends at 12:08 am MDT, July 17. Themoon wil l b e i n th e penumbra l shado w fo rapproximately 1 h 20 m befor e and afte r thesetimes. See the Summe r 197 9 issue of Stardustfor informatio n o n ho w t o photograp h luna reclipses.

MERCURY: I t i s visible lo w i n th e wes t a t th ebeginning o f Jun e afte r th e mos t favourabl eevening elongatio n o f th e yea r o n Ma y 26. Itsmorning appearanc e i n mid-Jul y is , however,not very suitable for norther n observers .

VENUS: It is beginning t o appear intheeveningsky, and by the end of June it is near Castor andPollux lo w in the west. Its phase is gibbous. Bythe end of August, Jupiter and Saturn will havejoined Venu s low i n the western sky at sunset.

MARS: Durin g Jun e an d July , Mar s i s a 2n dmagnitude mornin g object , movin g throug hTaurus int o Gemini.

JUPITER: Jupite r continue s t o b e prominen tthroughout June and July, with Saturn nearby.By mid-August , Jupiter wil l b e very low i n thesouth-west.

SATURN: I n Virg o alon g wit h Jupiter , Satur nremains visibl e in the west until September orso. Th e ring s ar e no w incline d t o ou r lin e ofsight by about 6° . Jus t when you thought you

had theSaturnian system of moons figured out,Brad Smith of NASA's Lunar and Planetary Labreports th e discover y o f stil l mor e satellites .1981 S 1 and 198 1 S2 have been found orbitingthe plane t a t the L 4 and L 5 libration point s o fTethys, abou t 60 ° precedin g an d followin gTethys i n it s 1 d 2 1 h orbit . Evidently,th e L 4object, 1981 S1, was photographed b y Voyager1 las t November . (From IAU Circula r 3602}

URANUS: I t i s easily found i n Libra , nea r theLibra-Scorpius border . See p. 87 of the RASCObserver's Handbook for a finder chart. Its diskmeasures about 3. 9 seconds o f arc.

NEPTUNE: I n opposition o n June 14, Neptunerises nea r sunset. I t is in southern Ophiuchus ,sporting a disk 2.5 arc seconds i n diameter .

oo/erving octMtie /The first official Buck Mountai n observing

session for the current season was held back inApril. O n Friday , Apri l 3 , severa l member sobserved from the lower site without problemswith muddy entrance roads. Two 30cm scopes,a 25cm , an d a coupl e o f 20c m scope s werepresent, quite a gathering of glass at Buck! Thenext night , observer s tried onc e agai n fo r a nevening o f viewin g bu t cloud s move d in .Meanwhile in the southern part of the provinceDave Beal e an d Ala n Dye r se t u p a t CypressHills Prov . Park for a weekend of astronomy atthe souther n latitud e o f 49.5° ! The y wer etreated t o clea r skie s Saturday; howeve r theyhad also planned t o observe an occupation bythe asteroi d Aegin a o n th e Frida y night , bu tnature planned otherwis e — it snowed.

JUNENo deep-sk y observin g session s ar e

planned fo r Jun e du e t o th e interferenc e ofperpetual twilight , which i s in effect fro m May12 to Aug . 5 or so at our latitude .

The bi g even t fo r Jun e i s th e annua lSolstice Celebratio n a t Buc k Mountain , thi syear schedule d fo r Saturday , Jun e 20 . Th e

festivities get underway at about 9:00 pm or so,in time for th e celebrants to watch the sun notset. See page 23 for details .

The Jun e Observer' s Corner, o n Monday,June 22 at 8:00pm, will feature a talk and slideshow b y Dav e Belcher, Darrel l Cross , et a l ontheir recen t tri p t o Arizon a and Ne w Mexico .There wil l be lots o f slides and stories of theirvisits to the Lowel l Observatory , Kit t Peak , theMultiple Mirro r Telescope , and th e V.L.A. , aswell a s photo s o f othe r attraction s lik e th eGrand Canyon , Monumen t Valley , etc . The yshould have some fabulous astro-photograph yto sho w a s well . B e sure t o atten d thi s livel ymeeting! The location is Rm. 445 of the PhysicsBldg., U . of A . campus.

At th e en d o f June , man y of th e Centre' smembers wil l b e of f t o Victori a to atten d th eGeneral Assembly. Don't forget their observingcompetition. I f yo u hav e som e astrophoto -graphy or results from observing projects , whynot conside r an entr y int o the contest ? Theprizes each year are usually quite enticing. Formore informatio n o n th e contest , contac tObserving Co-ordinato r Darrel l Cros s a t 469-2931.

27

Once again , ther e i s n o schedule d deep -sky observin g sessio n this month .

The July Observer' s Corner, Monday, July27 at 8:00pm, will centre around a feature talk byDr. Doug Hub e of the U. of A. Physics Dept. onthe observatio n an d importanc e o f asteroi doccultations. Watchin g asteroids pas s in frontof fain t stars has become a popular fiel d latel yfor amateu r astronomers . Th e size s o f th easteroids can be determined this way, and therehave been report s of possibl e asteroid moons.This i s an are a of researc h wher e the traine damateur can contribute usefu l results — plan toattend t o find out how. The meeting wil l likel yalso includ e variou s member s presenting thei rimpressions an d slides of the Victori a G.A.

Again, the O.C. is in Rm. 445, Physics Bldg.AUGUST

The first post-twilight observing session isslated fo r th e Augus t lon g weekend , Friday,July 3 1 t o Monday , Augus t 3 , an d wha t asession i t is ! A weeken d o f campin g an dobserving is being set up for Plateau Mountain .This wil l b e a join t observin g sessio n wit hmembers o f th e Calgary Centr e and Medicin eHat Clubs . Som e wil l likel y b e arriving Frida ynight, bu t th e mai n observin g night s ar eSaturday, Aug. 1 and Sunday, Aug. 2 with returnhome scheduled for Monday . Thos e attendin gshould b e prepared fo r a 5 or 6 hour drive fromEdmonton to Plateau, and for a weekend of self-sufficient, primitiv e camping . Ther e ar e n ostores nearby , and n o facilities of any kin d ontop o f the mountain . Bu t the skies are dark !

Don't forge t th e Manitob a Astronomica lConvention i s als o happenin g tha t weekend ,under th e dar k skie s o f Ridin g Mountai nNational Par k nea r Dauphin , Manitoba . I f yo ulike your campin g or holida y weekend s a littlemore civilize d tha n th e condition s o n th ewindswept reache s of Platea u Mtn., this i s theevent for you. The couple o f hundred amateurand professiona l astronomer s fro m acros sNorth Americ a tha t ar e expecte d t o atten dshould mak e for a great weekend .

AstronomyLecturesat the

Provincial Museum

Monday, August 3Monday, August 1 0Monday, August 1 7Monday, August 2 4

Topics to be announced.Ail lectures are free to the public.

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RASC. EDMONTON CENTRE MEMBERSHI P APPLICATIO N FOR MPlease accep t m y application fo r membershi p m the Royal Astronomical Society ol Canada, EDMONTO NCENTRE (or 198 1 Enclose d is a cheque or money order for the appropriate fee $20.00to r Adults; $12.00forYouths 1 7 and under I understand that upon receip t of my application and fe« remittance, a membershipcard and a copy of th e 198 1 Observer s Handbook wtl l be mailed to my address (or can be picked u p at th enext monthl y genera l meeting) , an d that I will be placed on th e mailing list s (or RAS C publications.

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JUNE

S M T W T F S. I 2 3 4 5 67 & 9 10 11 12 13

14 15 16 17 18 19OBSERVER'S CORNER_2JJ| 2 3 24 25 •27Monday, June 22 " *

GENERAL MEETING -Monday, June 8

SUMMER SOLSTIC E CELEBRATIOturday, June 20

"A Galaxy of One" PREMIERESat the PlanetariumFriday, June 26

S M T W T F S VICTORI A GENERAL ASSEMBLYFri., June 2 6 - Mon., June 29

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12 13 14 15 16 17 18

OBSERVER'S CORNER-J£20 2 1 2 2 2 3 2 4 2 5Monday, July 27 26 ^ 2 8 2 9 3 0 3 1

TO:

AUGUSTS M T W T F S

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