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A S T R O N O T E S ISSN 0048-8682
The Newsletter Magazine of the Ottawa Centre of the RASC Vol. 22, No. 2 $5.00 a year February/March 1983
Editor.......Rolf Meier......4-A Arnold Dr......820-5784
Addresses___.Art Fraser......11-860 Cahill Dr...737-4110
Circulation...Barry Matthews...2237 Iris St......225-6600
OBSERVER'S GROUP MEETING - JANUARY 7, 1983 Dave Lauzon
Vice-Chairman Gary Susick opened the meeting at 8:20 with 33 people in attendance, with 6 non-members. Notices were given of the General Assembly to be held in Quebec City on May 20-23, and on the repaired lock at I.R.O.
The new coordinators for 1983 were introduced. (Names may be found in the December and January issues of Astronotes.
Our first speaker was Peter MacKinnon on the Shuttle Project. Peter says that it would be possible to design a project with the talent of individuals found right in the Ottawa Centre. This "Get-Away Package" would probably cost less than the observatory facilities at I.R.O. The problem is that we have the technology, but no project, so therefore people are asked to come up with ideas for a possible project. There will be meeting in February discussing this.
Second speaker of the night was Dave Lauzon, with his talk on meteors in 1983. Dave briefly discussed the main showers, and why more meteors are seen in the later part of the year.
The next speaker up was Jack Horwood with fascinating cassette tapes of the Quadrantids of 1983, and the theory of bouncing radio waves off of meteor trails. According to Jack's readings, the shower peaked at 15:00 E.S.T. on January 3, a few hours later than predictions.
Brian Burke was then up to talk about occultations in 1983. Two good grazes are coming up in April.
Frank Roy showed slides of aurora and deep sky objects.
Rob Dick was selling "stuff" that was hanging aroundin the basement of N.R.C. Such things were telescopes, tripods, and the ever-popular monolith. Rob also showed slides of the sun on his apartment wall showing new methods of documenting photographs.
Gary closed the meeting at 10:32 when people were invited for snacks.
DECEMBER'S LUNAR ECLIPSE Sandy Thuesen
The eclipse of December 30, 1982 turned out to be a little disappointing, at least in the Ottawa area. At 04:30 we went outside to find the moon drifting in and out of heavy cloud. It was tempting to give it a miss, but we reconsidered and twenty minutes later ended up in a cornfield observing clouds and waiting for something wonderful to happen. We didn't have to wait very long. At 05:10 the sky cleared briefly and the moon came into view with a slightly lopsided shadow covering about a third of its surface. It disappeared and then reappeared again at 05:16 for about ten minutes. At this point nearly half of its surface was covered in shadow and through binoculars surface detail was easily seen. This was probably the best view we had of the moon during the eclipse as cloud became progressively worse from this point on. From 05:26 onward the moon made only brief appearances now and again. However, we were able to follow the progress of the eclipse up to three minutes before totality, we waited another half hour, but the moon had gone for good.
Although the eclipse itself was not terribly exciting, there was excitement enough in the form of several mini-disasters. Five minutes after arrival the flashlight dropped to the ground and it has not worked since; both pencils broke; while shooting the partially eclipsed moon, the camera mirror snapped up and refused to return to place (my temperamental camera's reaction to excessive cold); the largest, loudest, (and probably meanest) dog in Nepean dropped by and witnessed the destruction of a lens cap between the heel of my boot and the ice and, finally, it took twenty minutes and half a bag of sand to get free of the patch of ice on which we parked.
Two nice things though Saturn was seen for the first time since August or September and from a fence post over the road a large owl spent about fifteen minutes observing us.
WHERE'S HALLEY'S COMET? Dave Fedosiewich
First of all, it's not really Halley's Comet but belongs to whoever observed a particularly brilliant comet in 1531, 1607, or 1682. Checking back through all available historical records, Edmund Halley came to the firm conclusion that there were many apparitions of previous brilliant comets which were most likely earlier apparitions of the 1682 comet. (Also, Halley preferred the pronunciation "Hawley". Everything you know is wrong!)
Halley predicted that the same comet would return in 1758. Unfortunately, he died in 1742. The comet was recovered on Christmas Day in 1758, and was the foundation for belief in the periodic nature of comets. Since then, Halley's Comet has returned twice, in 1835 and 1910.
My guess is that it will return again. In fact, it has! Below is the circular that announced its recovery.
Circular No. 3742
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Postal Address: Central Bureau for Astronomical Telegrams Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
TX 710-320-6842 ASTROGRAM CAM Telephone 617-864-5758
PERIODIC COMET HALLEY (1982i)
M. J. S. Belton and H. Butcher, Kitt Peak National Observatory, have confirmed the recovery of this comet using a cryogenic camera and charge-coupled device on the 4-m reflector. They have derived the following precise positions by averaging exposures over several minutes and superposing averaged records over several hours according to the assumed motion of the comet.
UT ?1950 ?1950
Oct. 18.38663 7h10m53s.38 + 9°31'11."7
20.38542 7 10 43.22 + 9 29 18.5
The comet's image is slightly fainter than V = 24 and the resulting perihelion time is T = 1986 Feb. 9.2-9.3 UT.
E. M. Shoemaker, California Institute of Technology, has identified a probable image of this object on an exposure by E. Helin and himself with the 1.2-m Schmidt telescope at Palomar. C. S. Shoemaker has measured the trail ends as follows:
1982 UT ? ?
Oct. 11.25764 23h36m36s.96 -37°46'35".2
11.27847 23 36 38.36 -37 46 48.1
The following improved orbital elements, by the undersigned, are based on all the available positions Sept. 14-Oct. 11:
T = 1982 Aug. 5.379 ET
? 158°.553 e = 0.39430
? = 158.461 1950.0 a = 2.10166 AU
i = 24.984 no = 0.323490
q = 1.27298 AU P - 3.05 years
1982 ET ?1950 ?l950 A r Mag.
Oct. 28 23h56m.89 -38°00'.8
Nov. 7 0 09.71 -36 41.4 0.816 1.534 19.3
17 0 23.06 -34 41.7
27 0 36.98 -32 14.8 1.045 1.630 20.0
Dec. 7 0 51.42 -29 30.7
1982 November 5 Brian G. Marsden
IT'S PLUTO TIME AGAIN Dave Fedosiewich
If life's been dull lately, and you'd like a real challenge, then it's time to find Pluto. The smallest and second most distant planet is coming to opposition next month and will be at its brightest at magnitude 13.7. Here's how to go about finding it.
The first thing to do is to get a copy of its path on a large scale atlas. An excellent map is provided in the Observer's Handbook and is really all you need. Next, you'll need a large telescope (8-inch or larger) with accurate alignment to the pole so that the setting circles will be accurate enough.
Once your scope is pointed in the right direction, choose an eyepiece that will yield low power with a wide field, and look for a familiar pattern that you've noticed on the finder chart. Any pattern within a few degrees is fine, since you can star-hop to the location that Pluto is expected to be at.
Once you have the right field, progress to a higher power eyepiece with a smaller field, but not so high as to lose the orientation. You will now find that Pluto is at the location predicted by the curve on the finder chart. The planet should appear fairly dim but easily distinguishable at 100x in I.R.O.'s 16-inch telescope under dark skies.
Well, that's it, right?
No, not quite. Check on the planet a few days later to make sure that it is indeed Pluto (You may doubt yourself on your first attempt). Sure enough, the planet will have moved in relation to the background stars.
A neat idea would be to find Pluto photographically. Take exposures of the "suspected" field a few days apart (3 days is plenty) using prime focus techniques. Sure enough, when you develop your exposures, one of the "stars" will appear to have moved. Now you have a "before" and "after" situation, not unlike what you see in shampoo commercials.
Let me know if you observe Pluto, and I'd like to see your results for comparison. I'd also like to see some description of your observations in Astronotes, or you could give a talk at the next Observer's Group meeting. If you have any questions, give me a call at 731-7583.
A WRAP-UP ON COMET AUSTIN Dave Fedosiewich
A few months before its perihelion, a 10th magnitude comet was discovered by an observer in New Plymouth, New Zealand. Rodney Austin first spotted the diffuse object on June 18, 1982 in the constellation Horologium. Once the orbital elements had been calculated, I.A.U. Circular 3706 announced that Comet Austin 1982g would "become a moderately bright object (m1=4) well north of the sun in mid-August."
The first signs of a tail were reported by C. McCraken and L. Brown of the Goddard Space Flight Centre using spectrograms obtained on August 26, only 2 days after perihelion. On September 4, John Bortle of Stormville, N.Y. reported a tail length of about 4' of arc observing with 10 x 50 binoculars. By September 20, Mr. Bortle noted a total visual magnitude for the comet of 7.8 with the help of 20 x 80 binoculars.
In the Ottawa Centre, conditions for observing the comet were great since clear skies dominated the late summer weeks. Despite many pleas by the author for reports of observations, only a few were ever received. Of particular interest are the observations made by Sandy Thuesen between August 17 and September 10. A summary of her observations are reproduced elsewhere in this issue. These are strictly binocular observations and are right on the money with predicted positions. Magnitude estimates range between 4.8 for Aug. 17, and 6.5-7.0 for Sept. 10. Most observations were made from her cottage in Wakefield, Quebec, under clear but sometimes hazy conditions.
By mid-November, Comet Austin had faded to about 10th magnitude as reported by Mr. Bortle. (It's interesting to note that fewer people will observe a bright comet that has faded over a faint comet that will not get any brighter).
Unfortunately, Comet Austin was the only bright comet of 1982, and has been the brightest of the eighties to date. Where are the comet hunters? Where are the comets?
Opposite are Sandy Thuesen's observations of Comet Austin.
VISIT TO WINDSOR CENTRE Linda Warren
While visiting Windsor over Christmas, I had contacted the Windsor Centre to 1) meet them and 2) to see if they were going to observe the eclipse on December 30th. (It was too cloudy, but my mom told me at 4:30 or so the clouds cleared all around the moon; she observed til 5:00 or so.)
But I had the opportunity to meet Randy Groundwater, Editor, and Lorison Durocher, Secretary. We talked (over cookies and tea) about our respective groups. They have a membership of about 42. Randy lives in LaSalle, about 30 minutes from Windsor, where he has a Celestron 8 in his backyard. The yard faces a "never to be lighted" field with an excellent horizon. He said the lights from Detroit don't interfere too much with his viewing. They then showed me their slides of members, Stellafane visits, and star nights.
All in all, it was a terrific visit which I enjoyed
immensely. Thank-you Randy and Lorison for your
hospitality. Hope to see you at the General Assembly.
CALENDAR OF COMING EVENTS
Friday, March 4 Observer's Group Meeting
Friday, March 11 Star Night - I.R.O.
Saturday, March 12 Star Night - I.R.O. - cloud day
Monday, March 14 New Moon
Friday, March 18 Astronotes due date
Monday, March 28 Full Moon - "Sap Moon"
Friday, April 1 Observer's Group Meeting
Notice: Anyone wanting to use the radio telescope at
I.R.O. please contact Frank Roy at 820-0874. Chart paper is available. Also, notes on radio astronomy fundamentals are available from Frank or Ken Tapping.
COMET HUNTING Dave Fedosiewich
Before anyone can follow a comet as it moves through the sky, someone has to find the darn thing. In early times, the term "comet hunter" did not apply since the telescope hadn't been invented. Also, most laypersons were not too thrilled at the idea of a comet in the skies since this usually meant bad luck, ill tidings, and doom. Modern man has done away with such superstitions, although a comet has recently coincided with pay-TV.
Comet hunting can be said to have started with Charles Messier, who used a 60 millimeter refractor for the majority of his comets. By today's standards, this would be considered unsuitable (it should be noted that Messier did most of his sweeping at 5X magnification). Nowadays, the rich-field telescope is considered to be the best instrument available to the comet hunter, but more on instrumentation later.
The first factors to take into consideration before you begin are where and when to begin searching; in a way, one dictates the other. Most experienced observers will agree that the best time to hunt for comets is soon after sunset and soon before sunrise. The reason behind this is the fact that most brighter comets are discovered near the sun as they approach perihelion. This should not be adhered to as a rule of thumb since many comets are first spotted nowhere near the sun, although these tend to be a bit fainter. On the other hand; the fainter the comet, the better the chance that it has not yet been discovered. In any case, it's up to to the individual to design his/her own plan of attack.
Methods used for comet hunting vary quite a bit from observer to observer, but most conform to the basic idea of searching slowly and methodically. Experience has shown that the careful examination of small portions of sky from night to night yield the best results per expended hours of observation. Of course, the observer's actual course of action will depend on the size and/or magnification of the instrument used, his/her local sky conditions, his/her time available, and his/her temperament.
Of greatest importance to the comet hunter is his/her knowledge of the night sky. Someone who is constantly turning his/her attention to an atlas at the first sight of a nebulous object will be wasting a lot of time, not to mention a lot of patience. No one is expected to learn the N.G.C. catalogue by heart, but being able to identify the more popular nebular objects takes a long record of experience at the eyepiece.
HOW I SPENT MY WINTER VACATION Rolf Meier
On December 27, I left behind an Ottawa winter for the southern skies of Tucson, Arizona. This was my third year in a row to visit David Levy. I was joined by Eric Clinton of the London Centre.
The first four days of my stay were not very good for observing; in fact the weather was worse than when I had left Ottawa. Around Christmas, you may recall, temperatures reached +15° C in Ottawa. In Tucson, by contrast, it was down around +5° C, and cloudy. It even snowed in the mountains. As luck would have it, the eclipse of December 30 was almost totally clouded out!
Then, however, a remarkable thing happened. By December 31 it had cleared up, and not a single cloud was seen for the next 17 days, until my departure on the 17th of January. It warmed up to about 20° C.
This provided some excellent observing opportunities. I attempted some deep sky photography using one of David's telescopes, a 4-inch f/4. My best success was a 10-minute exposure of the cluster Omega Centauri, which reached the meridian at about 5 am.
The most memorable visual observation was of the Horsehead Nebula with David's 16-inch f/5 telescope. Using a 16-mm eyepiece, the nebula was well seen, but the greatest surprise was when we tried a 20-mm eyepiece in conjunction with a nebular filter. The Horsehead then stood out remarkably well. It must have been that particular combination of nebular filter (brand unknown), nebular spectrum, and excellent transparency which gave the fantastic view. All experienced observers present agreed that this sight was just astounding.
In addition, I made many observations of galaxies for my supernova search program, as well as many other deep sky objects. The planet Mercury was observed on several occasions, and the zodiacal light was seen every night.
One highlight of this vacation was a trip taken by David, Eric, Mike Magee, and myself. We travelled to San Diego and Los Angeles, visiting Palomar, Wilson, and Griffith Park Observatories. In Riverside, we enjoyed the hospitality of Cliff Holmes, the organizer of the Riverside Telescope Maker's Convention. On our return journey, we went to the Grand Canyon. We observed from its 7000-foot rim at midnight. Talk about dark, clear skies! We observed sunrise at the rim, and later in the day hiked down into the canyon. Continuing south, we passed through Flagstaff, stopping to visit the observatories of amateur Bob Fried, as well as the Lowell Observatory, with a tour given by Charles Capan.
Thanks go to David Levy for putting up with us for yet another year. And, he has invited us to visit again, which we all look forward to.
FROM OTHER CLUBS
Edmonton: The newsletter Stardust, once a proud 20-page
publication costing $3000 a year, has been reduced to a 4-page Xeroxed pamphlet as a result of Planetarium budget cuts.
London: Peter Jedicke is now this centre's official
observer of double stars.
Vancouver: Former Astronotes editor Tom Tothill is working on a 16-inch mirror with a 70-inch focal length. He is also editing the Vancouver Newsletter Nova with a word processor.
Winnipeg: Guy Wescott, Andrew Lawless, and Daniel Lawless successfully observed the total eclipse of the moon on December 30th from that centre's Glenlea Observatory.
Scranton, PA: Editor Jo-Ann Pluciennik gives us the following quotation from the poem "The Star Splitter":
"I recollect a night of broken clouds And underfoot snow melted down to ice,
And melting further in the wind to mud.
Bradford and I had out the telescope.
We spread our two legs as we spread its three,
Pointed our thoughts the way we pointed it,
And standing at our leisure till the day broke.
Said some of the best things we ever said."
AAVSO: The spring meeting will be held in conjunction with the RASC in Quebec City on May 20-23.
Wanted: Astronotes from volume 1 issue 1 to volume 12
issue 1. Contact Frank Roy at 820-0874.