Hamilton Amateur Astronomers October 1998 Volume 5 Issue 11 The Three Wise Men Denise Kaisler kaisler@astro.ucla.edu Y period of Halley's comet a full millennium before Halley himself ou know, the more I saw the pattern, in a time when the travel, the easier it is to gears of European science were see how ethnocentric our slowed by religious persecution and history books really are. the fall of Rome. Take ancient astronomy for example. Yet during this dark time, on the If you ask someone to list some other side of the world was well-lit - famous astronomers of yore, you'll - a fact due in part to the probably hear names like Aristarchus, astronomers of ancient China. Three Ptolemy, Copernicus, and Kepler. It's men in particular are thought of as right and good that these names stick h a v i n g m a d e o u t s t a n d i n g in our memories. They were brilliant contributions. After reading about Figure 1: Zhang Heng (79 - 149 A.D.) men and deserve recognition. Yet their lives, perhaps you will feel the looking deservedly smug. there are many other astronomers who same way. are not commonly known, merely 124 constellations consisting of a total because they didn't live in the culture Zhang Heng of the Eastern Han of 2500 stars, 320 of which were that gave rise to ours. Dynasty bright stars with names. "This is not including [those] observed by A case in point is that of China. This One of the premier intellects of the sailors," he wrote. "Of the small stars, nation has had a long history of ancient world was undoubtedly there are eleven thousand five astronomical successes. For example, Zhang Heng (78-139 A.D.). In his hundred and twenty." in 1054 A.D., astronomers in the home country he is renowned for Middle Kingdom recorded the nova many things. First of all, he was one However, Zhang was not satisfied that gave rise to the Crab Nebula. of Emperor An Ti's chief ministers. with his paper maps of the sky. When They noted the brightness of this Beyond that, he excelled in writing his charts were complete, hired "new star" and how it glittered for and visual arts, in fact he is craftsmen to build what may have several months before fading from presently considered one of the four been the word's oldest three- view. Yet the European record does great painters of his era. To top it dimensional models of the heavens. not mention this astronomical event at off, he was also the first man to The first globes were made out of all. invent seismograph and the bamboo strips, but eventually he odometer, or "mileage cart". commissioned a bronze version that Chinese astronomical records also was almost five meters in indicate that their observers were Yet Zhang's greatest contributions circumference. This in itself would making remarkable discoveries long were in the field of astronomy. have been a singular accomplishment, before their European counterparts Intense powers of concentration but Zhang took it one step further. He ever drew breath. These ancient sages allowed him to draw a detailed map used the power of water to make his are known to have calculated the of the heavens. His chart showed globe complete one rotation every (Continued on page 6) Chair's Report page 2 Constellation of the Month page 8 inside... HAA Fall Star Party page 3 November Star Chart page 9 Rob'serving Report page 4 Calendar of Events page 10 Page 2 Chair's Report a really neat example of what can be done with Java. It is a simulation of 500 artificial satellites that are II would like to start this month's Chair's Report by thanking the orbiting the Earth and you can council for the all the work they put in choose the simulation speed. The this year. Special thanks go to Rosa next page at Assalone and Juliana Light for their http://deathstar.phys.sci.chula.ac.th/ last minute filling in for positions that ~piak/astrmail.html is a list of EE vent Horizon is a publication of the Hamilton Amateur went vacant due to people moving. astronomy related mailing lists. Astronomers (HAA). On November 1st a new council will Among the lists is "NASA News" take over the duties of running the which covers NASA press releases The HAA is an amateur astronomy HAA. They say that time flies when and other information, "Online from club dedicated to the promotion and you are having fun. This past year has Jupiter" gives updates about the enjoyment of astronomy for people of gone by very quickly for me. It's hard study of Jupiter from NASA's Ames all ages and experience levels to believe that the HAA will have its Research Center and "ATM" which fifth birthday next month! is about Amateur Telescope The cost of the subscription is Making. This page includes included in the $15 individual or $20 Before you buy yourself a telescope instructions on subscribing to these family membership fee for the year. or accessory for Christmas make sure lists. Event Horizon is published a that you attend our December general minimum of 10 times a year. meeting. We will cover subjects such Don't forget about the upcoming as what to look for in a telescope, meteor showers for October and HAA Council eyepiece filters, solar filters, choosing November. The Orionids peak on Chair Stewart Attlesey eyepieces, the best star charts and the 22nd of October and the Leonids Second Chair Grant Dixon accessories that you can make for peak on the 17th of November. Secretary Marg Walton yourself. Treasurer Barbara Wight Stewart Attlesey Education Dir. Grant Dixon There are two sites that I am attlesey@interlog.com Obs. Dir Tony Wallace recommending a visit to this month. Editor Rosa Assalone The first one at http://liftoff.msfc.nasa. Membership Dir. Juliana Light gov/realtime/jtrack/3d/JTrack3d.html is HAJA Coord Rosa Assalone Councillors Ann Tekatch Rob Roy Editor's Report Ray Badgerow Juliana Light Doug Welch TT here was an incredible response to my request for articles this month. Thank you, to Web Site everyone who contributed to this http://amateurastronomy.org/ month's issue. So many people sent me articles that I couldn't fit them all in this month's newsletter. However, Friday, November 6th. You can e- anything that did not fit will appear in mail your articles and pictures to me the November issue. at assalor@mcmaster.ca or call me at 540-8793 for alternative Don't forget to check the calendar of arrangements. events for a summary of the things happening in the next month so you don't miss out on anything exciting. Rosa Assalone assalor@mcmaster.ca The deadline for the next issue is Event Horizon - Hamilton Amateur Astronomers Page 3 HAA Fall Star Party Magazine FF Discounts for collimation takes only seconds so it HAA Members is no real hardship. After that I was or those of you who didn't happy with the view. At 280X show up at the HAA fall star Jupiter was rock steady in the party, this is what you missed. I have viewfinder. Jupiter's Great Red Spot A A been observing for about 11 years and was actually a dark rimmed pale s a member of the the conditions at Silent Lake were the oval with a small off-centre deep H a m i l t o n A m a t e u r best I have ever seen. I will go one orange spot. There were 3 smaller Astronomers you are eligible for step further and say that the spots leading away from the Great subscription discounts for the conditions were spectacular. There Red Spot. Another obvious feature following magazines: was no wind, the temperature was was a large festoon on the North comfortable and there were no bugs. Equatorial Belt. Saturn at 375X Sky and Telescope: $37 U.S. funds looked wonderful, with pale brown per year (12 issues) We knew that the sky was really dark banding on its "surface". You could so we checked the RASC handbook, drive the proverbial truck through Astronomy Magazine:$35 U.S. funds which has a guide to rate the the sharp edged Cassini's division. per year (12 issues) transparency. Each of us who tried The B ring, which sits on the inside was able to see the faintest star listed, of Cassini's division , clearly The regular rates for Canadian which was magnitude 7.4! The Veil displayed gradations in brightness subscriptions are: Nebula in Cygnus was easily visible and the C or crepe ring was obvious Astronomy Magazine: $50 US in my 70mm f/6.8 at 14X with no to me for the first time. When Sky and Telescope: $ 46.95 US filter. We may have glimpsed M33 conditions are this good the time naked eye but I wouldn't swear to it. really flies. The first night we were That's a savings of $10-15 US or At one point after midnight on Friday up until 5 am. On Saturday night $15.50-23.25 CDN!! Atilla Denko, from the Ottawa Centre conditions weren't quite as of the RASC, asked if we wanted to spectacular but still better than If you are interested in subscribing to see Jupiter in his 25" Obsession that anything you can see close to either of these magazines or wish to was equipped with binoviewers. He Hamilton. We only stayed up until renew an existing subscription at club suggested that it would be worth 4am that night. As you can imagine, rates, please contact Ann Tekatch at losing our dark adaption. I wasn't staying up late means that you don't 575-5433. You need to fill our your prepared for what I was about to see. I get too much done during the day. subscription form with either an have N*E*V*E*R seen such a In a way that's a shame since Silent enclosed US money order, or with spectacular view of the planet. It was Lake is such a nice provincial park. your VISA number filled in. All like looking at the finest colour orders must be given to Ann, who will drawing. Of course, I had to see what Members of other clubs in southern send them on to the appropriate my 20" scope could do. Jupiter wasn't Ontario outnumbered those of us magazine. as good as I expected so I decided to from the HAA who went to Silent check my collimation. It was way off Lake. We had more inches of even though I had collimated it when aperture per attendee than most star it was first set up, as is my usual parties, with two 20" and one 25" practice. Since then I have noticed scope plus other assorted scopes. It's a Girl! that during the night collimation goes We will repeat both our spring and off and needs to be checked fall star parties in 1999 so watch for periodically. Before you get the notices in Event Horizon. concerned about your Newtonian O n Saturday, scope there are a couple of factors that September 12, Stewart Attlesey contribute to this. A truss tube design 1998, at 5:30am, attlesey@interlog.com means the scope is set up just a little Ann and Bill Tekatch became different each time, which makes it t h e p r o u d necessary to collimate the scope parents of whenever it is put together. On A l e x a n d r a Obsession telescopes a nylon sling is M i c h e l l e used to radially support the mirror and Tekatch. She this sling changes length with weighed in at a variations in temperature and humidity. With help, touching up the Event Horizon - Hamilton Amateur Astronomers Page 4 Rob'serving Report Jupiter's Satellite Phenomena 25 between 01:00-07:00 UT II 'm glad to be coming back in November as observing afterwards. Jupiter is setting earlier director after a year's absence. Having just passed opposition on each day. "Sky and Telescope" Weather willing, let's make it a record Sep. 15, Jupiter is visible for most includes Jupiter's satellite phenomena year for observing at the Binbrook of the night and has been in their monthly issues. It's great stuff Conservation Area. Remember, you spectacular! Possibilities are: a to observe. Have fun! don't need a scope to participate! On TRANSIT of a satellite or its Fri., Sep. 18, we had 8 people and 2 SHADOW across the face of the Jupiter's Red Spot telescopes - it worked out just great. planet, an OCCULTATION as it Besides, what better way to find out passes behind the planet, or an I don't usually include times for the what kind of scope you might want to ECLIPSE by Jupiter's shadow. transit of the red spot across the buy for yourself? centre of the disk (the meridian), but Starting with this issue, shadow I'm going to as long as it remains Binbrook observing nights are transit times will be listed which visible and so spectacular. After each scheduled for the Fridays and occur between evening and morning date the meridian transit time is given Saturdays just before and after New twilight. Times are converted to in (EDT or EST) to the nearest hour Moon each month. See calendar and EDT or EST. The first time is the AHEAD, so you will see it near but map handout for 1998. The calendar start of the shadow crossing not necessarily on the centreline of for 1999 is in the works and will (ingress) and the second is the end the disk. Because Jupiter's day is less included in the December issue of (egress). *- only one of the shadow's than 10 hours, you often may have "Event Horizon". Call Rob Roy at ingress and egress times may be two transits in one day (morning then 692-3245 for local weather conditions listed when the other occurs before evening) or two per night on and to confirm. If you have any ideas evening twilight or after consecutive days (evening then for observing events for the upcoming Jupiter has set. morning). If you want exact transit year, please call or e-mail me: times, "Sky and Telescope" lists them A window of UT (Universal Times) in Universal Time for each day of the will also be given so you can search month. As you read further, you can guess in "Sky and Telescope" and in the what one of my favourite objects is- "RASC Handbook -1998" for other Oct 11(12am)(8pm), 13(1a)(9p), 15 Jupiter. I'm going to include Jupiter's events you may wish to observe. (11p), 18(12a)(8p), 20(2a)(10p), 22 Satellite and Red Spot Phenomena for Events on either side of this window (11p), 25(1a)(9p), 26(6a), 27(9p), as long as it's vis ible. PLEASE make occur either before evening twilight 29(11p), 30(7p) use of the data- all of the hard work or after Jupiter has set. To get your has been done for you! For your ease local EDT subtract 4 hours from the Nov 1(1a)(9p), 3(2a)(10p), 6(12a) and convenience, times have been UT shown for each event until Oct. (8p), 8(2a)(10p), 10(11p), 11(7p), converted to Eastern Daylight Time 25 after which you subtract 5 hours. 13(1a). (EDT) or Eastern Standard Time (EST) after Oct. 25. Now you have a Oct 12 Io 04:15 EDT ---> * Monthly In-Sights good reason to carry your EH with 13 Ganymede 19:51 ---> 23:02 you whenever you go observing. 14 Europa 01:00 ---> 03:40 October 15 Io 01:43 ---> 02:58 * 18- Moonless two-week period for 28 Ganymede 02:55 ---> * seeing Zodiacal light in the eastern 28 Callisto 21:45 ---> 23:07 sky before dawn. 29 Io 03:34 ---> * * 19- Orionid meteor shower 30 Io 22:03 ---> 00:18 (31st.) (visible only after 11pm)lasts for 31 Io * ---> 21:08 about one week peaking on Oct. 22 at 3am. Nov 06 Io 23:59 ---> 02:13 (7th.) * 20- New Moon 07 Io 21:05 ---> 23:44 * 23-3pm Saturn at opposition. 08 Io * ---> 22:42 * 25- Daylight Time ends, Eastern Standard Time begins. For other events, search the table in the "RASC Handbook", page 165-6, between 00:00-08:00 UT until Oct. Event Horizon - Hamilton Amateur Astronomers (Continued on page 5) Page 5 (Continued from page 4) November * 03-2am S. Taurid meteor shower peaks. * 04- Largest Full Moon of 1998. * 05- Aldebaran occulted by the Moon. 7:31-7:56pm. * 11- M e r c u r y a t g r e atest TT he next meeting of the elongation, 23 degrees east of the Junior group is Tuesday, Did you know western dusk October 20th, 1998. If you know of * horizon. that.... any child under the age of 12 who is * 13-1am N. Taurid meteor shower interested in astronomy, this is the peaks. Jupiter takes 12 years to group for them. * 17-Possible Leonid meteor c i r c u m n a v i g a t e t h e STORM! Zodiac, spending about The group meets once a month on one year in each the third Tuesday at 7:00pm. constellation as it travels Meetings are held in McMaster's * Mercury is an evening "star", eastward. Burke Science Building in room visible in the Nov. western B148. twilight sky, reaching its highest elevation on Nov 11. For more information call Rosa * Venus is too close to the Sun for Assalone at 540-8793. observation until Jan. 1999. * Mars rises after midnight in Leo. Very small diameter- not much of a telescope object. * Jupiter is visible in the evening Internet Searches in Astronomy until around 2am. Spectacular! Stationary on Nov. 14, after which by Ray Badgerow it resumes direct eastward motion. * Saturn is visible all night long. At opposition on Oct. 23 its 20" disk is the largest in over a decade. T his article is about something I did a little while ago ,as I thought about That and the appreciable tilt of the something to write about.So I did some searches for various topics at the rings make it a nice fall object! Astrophysical Data System (ADS) at http://adswww.harvard.edu/ Try to find the Cassini Division ads_services.htm. This is a sample of what I did in only a half-hour while in the close to the outer edge of the Mohawk College computer room. rings. The three smaller satellites Rhea, and especially Dione and Topic Time Period # of Articles Tethys are challenges for small Space Missions: telescopes. Viking Mars Mission 1976- present 2147 * Neptune & Uranus are a bit west Voyager Mission 1979- present 2606 of Jupiter in Capricornus in the Galileo Jupiter Mission 1995- present 2175 evening sky. Hipparcos 1993- present 336 Hubble Space Telescope 1990- present 7353 Rob Roy Mars Pathfinder 1992- present 2191 Comets: 1P/Halley 1982- present 2387 P/ Shoemaker-Levy 9 1993- present 2706 C/1996B2 Hyakutake 1996-present 1567 Extrasolar Planets 1982- present 26928 1995- present 5189 Doug "Macho Man" Welch 1982- present 137 Event Horizon - Hamilton Amateur Astronomers Page 6 Wise Men.... moon was so much thinner than when they had set out two weeks But Zu Chongzhi wasn't dis heartened (continued) ago. The elder Zu did not know the by this setback. Instead, he turned his (Continued from page 1) answer, but gave his son a book to attention to calculating a value for pi. year, showing how the positions of read. It was an astronomy text Zu wanted to see if he could obtain a the stars changed from one winter written by none other than Zhang more accurate value than Zhang Heng solstice to the next. Zhang Heng's Heng. had done. invention is known as the water- powered celestial sphere. Zu's father fostered his son's interest To perform the calculation, Zu in the stars by apprenticing him to Chongzhi used a method of polygons. By adding a few additional gears, He Chengtian, a learned man of the This geometrical scheme was Zhang was able to drive a pillar that time. While studying with Scholar strikingly similar to the argument demonstrated the waxing and waning He, Zu noticed a discrepancy Archimedes used to achieve his of the moon. Remarkable, if one takes between a sundial's shadow and the famous result 223/71 < pi < 22/7. It into account that Zhang Heng official calendar then in use. His was unlikely that Zu knew of believed in an earth-centered master agreed that the calendar had Archimedes' work. Still, Zu universe. In one of his classic texts its problems and together they understood that the circumference of a on the nature of the sky, he wrote that gathered enough data to correct hexagon was equal to exactly three the heavens were like an egg with the them. He Chengtian's new system times its diameter. But if he cut off earth in place of the golden yolk. was called the Yuanjia calendar. the corners off the hexagon and made it into a dodecagon, that ratio became However, there were two other Yet even this calendar was not slightly larger than three. Zu cosmologies known to the ancient completely accurate. By the time Zu Chongzhi painstakingly drew and Chinese. One stated that the earth was Chongzhi was a mature man, he a large square, 400 000 kilometers on noticed that it could not account for a side and the sky was a spherical some of the solar eclipses so canopy that rotated counterclockwise important to the imperial court. while the sun and moon moved in the opposite direction. A third theory Zu was successful in producing a boldly asserted that the sky had no new system, but, as so often fixed shape and the celestial bodies happens in astronomy, the new idea merely floated around in it. got tangled up in red tape. Ministers of the imperial court spent two years Zhang Heng did not subscribe to this arguing about whether they should last view. Instead, his cosmology was use the new Daming calendar and like the value of 3.1622 which he might have gone on even longer if once obtained for pi -- a good the emperor of the time hadn't Figure 3: A five yuan commemorative approximation and remarkable for its passed away. With the death of the silver coin depicting Zu Chongzhi. To the time, but not entirely accurate. Of old emperor, discussion of what to left is a diagram similar to Fig. 2. course, the same may one day be said do with the Daming calendar was of Einstein's work. postponed indefinitely. measured a polygon with 192 sides, eventually finding pi to be equal to Zu Chongzhi, Astronomer and 355/113 or 3.1415929, a value which Mathematician is correct to six decimal places. Such precision was not surpassed until until Another great scholar who was the 15th century A.D., when Al'Kashi, concerned with finding the value of pi a native of Samarkand (now was Zu Chongzhi (429-500 A.D.). Uzbekistan), calculated pi using a From a very young age, he was similar method. interested in astronomy and mathematics. Legend has it that when Although Zu Chongzhi's perseverance he was ten years old, Zu accompanied in deriving pi is exceptional, it is his father on a trip to a construction even more astonishing when one site, which it was his father's job to considers that his work predated even oversee. As they returned from the the abacus. Zu had to do all his trip, young Zu wondered why the calculations using nothing more than wooden counting sticks. Figure 2: The method of polygons used by Aristarchus and Zu Chongzhi to approximate a value for pi. Event Horizon - Hamilton Amateur Astronomers (Continued on page 7) Page 7 (Continued from page 6) The device had several nested sets "Zu Chongzhi" It was mainly for this contribution of circular rings. With them, Yi z: like the ds in "suds" that Zu Chongzhi received a singular Xing and Liang Lingzan could u: like the u in "flute" honor. He is one of the few Chinese determine the true solar time. They ch: as in English, but with the tongue mathematicians to have a lunar could also calculate the declinations curled back feature named after him. Crater Zu of celestial objects and measure o: like the o in "or" Chongzhi (listed in the IAU's differences in right ascensions. i: like the ee in "meet" handbook as Crater Tsu Chung Chi) is 28 km wide and is located about 20 The two men also built a water- "Yi Xing" degrees north of the moon's equator. driven celestial sphere. It was based x: like the sh in "shine" on Zhang Heng's design, but However, despite his mathematical included separate tracks for a model victories, Zu Chongzhi never saw his sun and moon. These two orbs were Daming calendar put to use. It took calibrated so that they would circle years of effort by Zu's dutiful son the bronze globe once every 29 days before the calendar was at last and once every 365.25 days recognized, a decade after his father's respectively. death. With these instruments, Yi Xing The Brilliant Monk Yi Xing was able to get more accurate data on the movements of celestial Yet even though the Daming calendar bodies. He finished the first draft of was as accurate as Zu could manage, his new Dayan calendar just before it too contained errors. Eventually it his death in 727 A.D. The Dayan fell into disuse. Other calendars came calendar was so accurate and well- and went, but they were little better organized that it remained in use HAA E-mail than the one created by Zu. until the sixteenth century A.D. Checklist By the year 721 A.D., the calendar A century later, Jesuit missionaries was again in serious need of reform. brought European astronomy to The emperor at the time once waited China. For the first time in history, O O c a n c n Mon., Oct. 5, an e-mail an entire day for a solar eclipse so he astronomers from the west and the notice was sent out so we could perform important rituals. far east began to exchange ideas. h e c k a n d u p d a t e o u r When the predicted eclipse did not And as you'll see in next month's membership's e-mail address book. occur, the emperor was furious. The Event Horizon, it wasn't a one-sided monarch promptly gave his advisor flow of information. If you DIDN'T get this notice it's Yi Xing the job of revising the faulty because: calendar. a- you're not on our list b- you're on the list but we don't have Yi Xing decided that he needed to your correct address take a detailed survey of the sky. Notes on Pronunciation: c- you don't even own a computer and However, the great bronze furthermore you don't give a hoot! instruments used by previous court Perhaps another reason why we astronomers had been so neglected don't often talk about Chinese If you fit into a or b and want to be that they were no longer adequate. Yi astronomers is that there names are included in notices sent out for events enlisted the help of one Liang so hard such as BCA observing nights or Lingzan to help build new ones. The t o say! meeting dates and speakers, please learned men collaborated for four T r y send a message to royrg@mcmail.cis. years and at last came up with a new wrapping your tongue around these mcmaster.ca and he will add you to type of instrument: the ecliptic three names using the guide below. the the address book. armilla. "Zhang Heng" Rob Roy The device was cast in bronze. Its zh : like the j in "judge" but with the enormous weight was offset by tongue curled towards the back of carefully filling its various hollow the mouth parts with water. When perfectly a : like the a in "father" balanced, the armilla was said to have e: like the u in "blur" responded to the touch of a finger. Event Horizon - Hamilton Amateur Astronomers Page 8 Constellation of the Month - Andromeda by Margaret Walton II n our summer issue we heard the story of Cepheus. Andromeda is the daughter of King Cepheus and Cassiopeia. Cassiopeia claimed that she and Andromeda were the most beautiful in the world. This angered the gods and they demanded that Andromeda be sacrificed to the sea-monster Cetus. The form of the constellation is that of a chained Andromeda waiting for the sea- monster. Perseus, who defeated the sea- monster, rescued her (more on this story next month, when Perseus is the constellation of the month). In Mesopotamia, this constellation was dedicated to the Egyptian goddess of love and war, Astate. Astate was worshipped in temp les M110 - This is another companion NGC891 - This is an edge-on spiral located along the shores of Palestine, to M31. It is bright, large and galaxy with a broad dust lane. It is the same shore that saw the chained somewhat elongated, with a very large and very elongated. The Andromeda. magnitude of 8.0. It was not an NGC rates this (!). original Messier object, but was Stars Stars added in 1967 by K. Glyn Jones. NGC7662- The Blue Snowball - This is a bright planetary nebula that can Gamma - this is a beautiful double NGC147 - This companion to M31 even be seen through binoculars. It is star. The brighter of the two is golden is a very faint, very large irregular/ very bright, small, round and quite yellow or light orange, while its round galaxy with a magnitude of blue. It has a magnitude of 8.3 and companion is greenish-blue. The 9.3. It is physically paired with the NGC rates this (!!!). companion is itself a close double. NGC185. Objects Objects NGC185 - Another companion to M31 - The Andromeda Galaxy. This M31, this is a bright, large round spiral galaxy is only 2.2 million light galaxy with a magnitude of 9.2. years away and is easily seen through binoculars and even naked eye. It has NGC404 - This is a bright, large a magnitude of 3.5 and the NGC rates round galaxy with a magnitude of this (!!!). This galaxy has 4 visible 10.1. companions described below. NGC752 - This binocular object is M32 - This is a bright, large round an open cluster with about 60 stars. galaxy with a magnitude of 8.2. It is It is extremely large and has a a companion to M31 and is the magnitude of 5.7. smallest of the Messier galaxies. The NGC rates this (!). NGC753 - This is a bright, large round galaxy with a magnitude of 12.4. Event Horizon - Hamilton Amateur Astronomers Page 9 Event Horizon - Hamilton Amateur Astronomers Page 10 COLLIMATE! COLLIMATE! COLLIMATE! - by Rob Roy supposed to resolve 0.56 seconds.", In use, when a fairly bright star (I you say. Not an SCT with a 14% W W hat's the nicest thing you can do for your scope? In one word - Collimate. used Altair) is out of focus you see central secondary obstruction! I am I used to think that my 8"/f10 SCT three star images in the form of a thrilled to get my scope to this point. was quite well collimated; just a few triangle. As you approach focus, weeks ago I had tweaked it a bit the three images converge. The Do your scope (and yourself) a favour again. Lately there has been a lot of three will only sit exactly on top of and make a 3-hole mask to collimate traffic on one of the Internet mail-lists one another if the collimation is your scope. You'll be amazed at the about a 3-hole focusing and bang on. Mine was a little off. difference. collimation mask. I have a 2-holer After some minor turning of the which can only be used for focusing, collimation screws, I thought, "If but I thought would take a few three little square inches didn't focus minutes to make a 3-holer. all in one spot as they're supposed to, imagine the visual mess that 64 Essentially I made a disk of cardboard non-concentric square inches would to fit in the large end of my scope and make!" I cut three 1&3/8" holes near its outer edge 120 degrees apart. I also cut a After careful collimation using this central hole large enough to fit the mask, I took my scope up to 454x (a mask over the secondary mirror la Sears $99 Saturday night support so I could easily get at the special!) and for the first time was collimation adjustment screws at the able to split a binary pair 0.8 arc front. seconds apart. "But an 8" scope is RASC Calendars and Observer's Handbooks The Observer's Handbooks and RASC calendars have been ordered and will be available at a future meeting. Handbooks will cost $14 and calendars $8. At these prices, they won't last long! Buy yours early! CALENDAR OF EVENTS * Tuesday, October 20th, 7:00 pm HAJA MEETING - McMaster Burke Science Building, room B148. For more information contact Rosa Assalone at 540-8793. * October 16, 17, 23, 24, 8:00pm BINBROOK OBSERVING NIGHTS - For confirmation or directions call Rob Roy at (905) 692-3245. * Wednesday, October 28th, 7:30pm HAA COUNCIL MEETING - At the home of Rob Roy. * Friday, November 13, 7:30pm HAA GENERAL MEETING - At the Spectator Building auditorium. * November 14, 20, 21, 8:00pm BINBROOK OBSERVING NIGHTS - For confirmation or directions call Rob Roy at (905) 692-3245. * Tuesday, November 17, 7:00pm HAJA MEETING - McMaster Burke Science Building, room B148. For more information contact Rosa Assalone at 540-8793. Event Horizon - Hamilton Amateur Astronomers