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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. 23, No. 7 $3.00 a year September 1984
Editor.......Rolf Meier.....4-A Arnold Dr.......820-5784
Addresses....Art Fraser.....92 Lillico Dr.......737-4110
Circulation...Robin Molson....2029 Garfield Ave...225-3082
After a busy summer, things are back to normal and once again Astronotes is being published. The July and August issues were missed for various reasons, but here is issue 7 of this volume. Until 1973, actually, Astronotes was only published 10 times a year. This corresponded to the number of Observers Group Meetings, which until that time did not meet in the summer. However, the group became very enthusiastic and summer meetings were instituted, together with summer Astronotes. Perhaps we are returning to the more laid back days, prior to the high that occurred within the last 10 years. In any case, the backlog of articles has not resulted in a huge issue.
The observing weather has not been very good for the last few months. While it has not exactly been rainy, it has been very humid, often hot, and usually cloudy. A great contrast to last summer, which was also hot, but usually clear. Not only that, but the few clear periods which were experienced this summer coincided with times
around full moon. Hopefully, the fall will see a return to drier conditions. Even the planets were disappointing. Mars made a brief appearance, but was very low. Jupiter
has also come and gone, low in the south, as well as Saturn. However, the movements of the planets were interesting to watch as they changed noticeably from night to night in the sky.
But enough of the complaints. Enjoy this issue of Astronotes, and if you have something to write about yourself, send it in as a contribution! It could be
anything from an observation, cartoon, a project, a trip report, things to build, things to observe, etc.
OBSERVER'S GROUP MEETING - AUGUST 3
Chairman Gary Susick opened the meeting at 8:22 pm with 35 people in attendance, of whom 28 were members. Many topics were discussed, such as various comets visible this month, star nights, and conventions. Last month, Gary Susick and Frank Roy presented a slide show for a science fiction convention. On August 24-26 at Mt. Forest, Ontario, Ken Tapping and Fred Lossing will be presenting talks at Starfest 84, presented by the North York Astronomical Society.
Vice-chairman Malcolm (As-Seen-On-TV) Lambourne talked about the July 21 Star Night. An excellent turnout was reported with 150 people and 10 telescopes present. The next Star Night will take place on August 24 or 25 at IRO.
Next up was Gary Susick, with a slide show demonstrating the scale of star fields as taken with various lenses. After the slide show, there was an open discussion on types of films and the duplication of slides.
Meteor coordinator David Lauzon gave a talk on the calculation of meteor trail altitudes. By using trigonometry and two observing stations, the meteor's height can be determined. Dave's talk ended with an open discussion on methods of observing and some aspects of the math involved.
Gary was up once more to tell members of the annual Deep Sky Weekend, to be held September 21-23.
Last up was Linda Meier, with a discussion about solar observing, and a "Sun Day" solar observing session planned for August 25.
Gary closed the meeting at 9:40, and people were invited for refreshments.
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OBSERVER'S GROUP MEETING - JUNE 1 David Lauzon
Chairman Gary Susick opened the meeting at 8:22 pm with 50 people in attendance, of whom 41 were members. Gary mentioned that Astronomy Day was a great success and thanks to those who helped. This meeting was the annual instrumentation meeting, and to start things off, Robin Molson spoke of IRO. He thanked all those who helped put the siding on the observatory.
Brian Burke spoke about the upcoming General Assembly. Members wishing to attend should consider the various packages and the possible presentation of talks or projects.
Gary Susick, speaking on behalf of Fred Lossing, mentioned the star nights on August 24-26 with the North York Astronomy Club. Also, the annual Deep Sky Weekend will be held on September 21-23 at IRO.
Dave Lauzon was up next to show members his 8-inch f/7 Newtonian he finished building. The horseshoe mount consists of a bicycle wheel, a barrel, and other material.
Jack Horwood brought with him a direct access receiver, which he uses for CHU time signals and for meteor bounces. The frequencies for time signals can be found on page 20 of the Handbook.
Paul Comision shared with members the description of his 6-inch f/4.92 rich field refractor. The objective was bought from Jaegers, and is a triplet. The telescope was made for a 2-inch eyepiece, and weighs 27 pounds. Paul's future plans are to adapt it to his C-11.
Simon Tsang was up next to show his rebuilt equatorial mounting, bought at Stellafane. Simon used various devices to improve performance.
Linda Warren (soon to be Meier) talked about her planetarium made out of a black umbrella. Phosphorescent stars on the inside glowed in the dark, and showed the constellations very well. Kids are really impressed by it.
On the observational side of the meeting, variable star coordinator Sandy Thuesen discussed the Variable Star Award and events on Astronomy Day. She showed many slides of how the public was bewildered by our activities on Astronomy Day.
Lunar and planetary coordinator Rolf Meier discussed the observing of Mars. The polar caps are small, but Martian clouds make them appear larger. He continued by showing drawings and photographs of the planet.
Occultation coordinator Brian Burke talked about the successful graze of May 6/7. There were 5 stations, and all observed an event or events. Future grazes will hopefully be even better, with stations being closer together.
Once again Jack Horwood was up, presenting a talk on last month's solar eclipse. Even though it was cloudy in Ottawa, Jack observed the eclipse with a photometer. A graph showed the approximate maximum of the eclipse.
Last up was Gary Susick, with a slide show of sky fog. He closed the meeting at 10:35, when people were invited for refreshments.
THE 50TH STELLAFANE MEETING
It was not only my second Stellafane, and one that will be most memorable not only for it being the 50th, but that it was a terrific end to our honeymoon!
Upon arriving Friday night the weather was not conducive for an outdoor event. However, some people were undaunted and they trampled through the downpour and the mud to attend the talks. (We were not among them.) Instead, we met friends at Hartness House and after dinner we had the opportunity to share and discuss Astronomy in the comfortable "armchairs" in the lobby of Hartness House.
The following morning we awoke to a brightly-shining sun with a tolerable temperature (not hot and humid like last year). At last! We were going up to the Hill, all the telescopes, the people, and boy, I really like the swap table. But most of all we looked forward to renewing old acquaintances, seeing fellow members, and meeting new people.
George Fortier of the Montreal Centre won two first prizes. We were pleased to see him again, and also very happy for him. It is a telescope that certainly deserved to win. It was made using special plywood with extra layers. The clock drive was also very well done and George had a friend who assisted him.
Duane Niehaus from Arizona, who travelled so far with his beautiful telescopes, won 3rd prize for optics with his 6-inch f/4. It truly is an exceptional instrument.
Martin Rochette from Quebec had an ingenious design which converted his Dobsonian to equatorial motion with a simple extra arm.
John Vogt from Long Island brought his 24-inch again, and with a nebular filter gave the most tremendous view of the Veil Nebula that I have ever seen. Simon Tsang can tell you about the view he saw of other objects. John also won 2nd prize for optics with his 14-inch Newtonian.
One telescope that we all felt was equal, even superior, was owned by Dave Kelly. It was the most remarkably rigid telescope ever built. That it did not win anything left me stunned. You could actually move the eyepiece up and down while observing and that telescope remained rock solid. It is something you would have to experience to appreciate.
Later that night, we also had the chance to look through the Porter Turret Telescope at M 13. The sky background was so unbelievably dark, and M 13 was something to behold.
The prelude to the main speaker that night, Mr. Ben Mayer, was a talk given by Fred Lossing, our own member. Sadly, we were just coming up the hill when Fred was speaking and we were very sorry to have missed his talk. Then the famous Walter Scott Houston was up to give an absolutely wonderful talk. He is always enjoyable to hear and of course everyone appreciates his sense of humour.
At dinner on Friday evening and again on Saturday evening, we had the pleasure of meeting the main speaker, Ben Mayer. A very remarkable man whose absolute ingenuity and love of astronomy (actually who loves life) was quite unforgettable. To discover that he has been "into" astronomy for 12 years was particularly inspiring, as I started getting interested only in recent years as well.
I've run out of adjectives to describe Stellafane,
So now I'm going to make it simple and plain,
Youll have to find out if all of this is true,
Next year when we go, I want to see YOU!
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THE 1984 GENERAL ASSEMBLY CONVENTION Louis Krushnisky
This year, the GA was held partly in Hamilton and partly in Niagara Falls, from June 29 to July 2. After an uneventful trip, Brian Burke, Frank Roy and I arrived at the beautiful campus of McMaster University, our home for the next 3 days. At registration, we all got time tables, brochures, maps, etc., and of course a frisbee.
That evening, to start things off, a Bavarian Bash was held, where everyone got to reacquaint themselves with old friends and to meet new people. The party was officially finished at 1 in the morning, but Ive heard some people had a sleepless night (eh Brian?)
The next day, the real convention started with paper sessions in the morning. Most of these talks were quite good. Noteworthy is the completion of the Amateur Sky Survey by Damien Lemay. With his Schmidt camera and 5 dedicated years, he photographed the whole sky visible from his home in Rimouski. He won the top award for the display competition.
Also, Malcolm Thompson of the Ottawa Centre gave a talk on timekeeping devices, as he was the director of that
department at NRC. He was immediately followed by Omer Lavallee of Canadian Pacific, who talked about the
evolution of time zones and how it affected train schedules. Mr. Lavallee finished by presenting to the RASC, through Dr. Thompson, a magnificent pendulum CPR time clock.
At the end of the session, everybody gathered outside for the group photo.
That afternoon, the annual meeting took place where it was decided that Edmonton would be the 1985 site of the GA. At the council meeting it was decided that Winnipeg would be the site of the 1986 GA.
The first of two banquets was held that evening, with guest lecturer astronaut Steve MacLean. He described the training Canadian astronauts received at NASA and their role in the space program. He was so informal and interesting that we had to interrupt the discussions to gather interested members who wanted to go to the Hamilton Observatory. Steve and a large group of us then moved to a lounge where we continued talking of his experiences until well past 2 am.
Sunday, after another morning of papers, we all departed for Niagara Falls on two buses. It seemed like we were back in Ottawa on the good old Queensway on our way there (bumper to bumper amid road construction) so much that the 20 to 30 minute trip on the QEW took us 2 hours. We were then only able to go under the falls, up the Skylon Tower, and glance at the floral clock and the whirlpool, all in a bus with no air conditioning in 30° C heat.
The second banquet was then held (no need to say informal dress). Here, the outgoing president, Dr. Franklin Loehde, presented a most impressive lecture on the new Edmonton Space Science Centre where the 1985 GA will be field. The structure, with its futuristic looks, could well attract more members than usual next year, especially because inside, besides the planetarium, there is the IMAX theatre where you feel you are in the movie. There are also laser shows and gallery displays, and a full-scale Canadarm coming out of the wall towards you.
The awards were also presented that night.
I should not forget that we are invited to Toronto next July for the 50th anniversary of the David Dunlop Observatory. The exact date will be published in a future National Newsletter.
To finish, let me say that we had a really great time. We would like to thank the members of the Hamilton and Niagara Falls Centres for their dedication and hard work for this GA.
GENERATING SIDEREAL TIME
Sidereal time is defined as the right ascension of the meridian, for a particular place. The meridian is the imaginary line running exactly north-south and passing through the zenith. It is, in fact, the interval in hours, minutes, and seconds since the preceding meridian passage of the first point of Aries.
The sidereal day gains on the mean solar day by 3m 56s because the earth has moved along in its orbit around the sun by one day.
A clock that keeps sidereal time would gain on mean solar time by one part in 365.2422, the length of the tropical year (equinox to equinox) in days, or one day in the orbit of the earth about the sun. Therefore, the mean sidereal gain is:
1 divided by 365.2422 = 0.002737909256
This means that for every second of standard time, sidereal time will have gained 0.002737909256 seconds. Or, the sidereal clock counts 1.002737909256 seconds for every standard second.
Several approaches are possible to obtain sidereal time for a particular area, for any time of year. The usual practice for calculating sidereal time is by the use of a table, such as the one provided by the Astronomical Almanac.
An easy approach is to use the equation provided by the Observer's Handbook:
GMST (Greenwich Mean Sidereal Time)
LMST (Local Mean Sidereal Time)
LMST = GMST - west longitude + east longitude
GMST at hour + UT on day d of the month = GMST at Oh UT on day 0 + 0.065710d + 1.002738t
The first day of the month is day 0 and t is in decimal hours.
As one can see, deriving an accurate sidereal time
requires knowing your longitude accurately. Fortunately, the Handbook provides accurate GMSTs. Topographical maps
can be used to measure your longitude to better than a second.
A clock can be used to run sidereal if the time base is replaced by a slightly faster one. Assuming a 60 Hz time base, the correction is:
Sidereal 60 Hz = 60 x 1.002737909
One way of generating this odd frequency is to use a high-frequency crystal and divide it down.
divide by n
The crystal oscillator can be any frequency but somewhere in the 1 to 10 MHz range seems to be the best compromise between accuracy and power consumption (assuming portable operation).
fxtal = 4.000000 MHz
n = 4000000/60.16427454
Then, fxtal = 66484 x 60.16427454
= 399721 Hz
From my experience, a crystal can be pulled by ±100 Hz from centre frequency, so the above example should present no problem in tuning it slightly lower. One could order a crystal cut to the exact frequency, by in any case a frequency counter should be used to fine-tune the crystal, and an oven can be used for long-term accuracy.
In my circuit, I use a CMOS crystal oscillator. A
4-decade programmable counter (n=2 to 9999) together with a divide-by-10 counter were used to divide the oscillator by 66480, resulting in the final frequency of 60.16427454 Hz.
References: Observer's Handbook 1984; Nortons Star Atlas,1973; The Astronomical Almanac, 1983.
VARIABLE STARS OF THE MONTH - R SCT, RZ CAS Sandy Thuesen
This month, two more program stars for the Variable Star Award are highlighted - R Sct and RZ Cas. A few facts on each of these two stars follow:
This star is located just 1° south of Beta Scuti and about 1° northwest of the star cluster M 11, which makes it very easy to find in binoculars. R Sct is a peculiar semi-regular variable, considered to be of the RV Tauri class (light curves typified by alternate deep and shallow minima). Neither the star's period nor amplitude is constant, its period being around 140 - 146 days, with the star rising at times to magnitude 4.8 or so and dipping usually to about 6.0. Every 4th or 5th minimum, however, is exceptionally low, dropping to 8.0 or fainter.
While in the area of R Sct, be sure to check out M 11 and, if you have a small telescope, the double star E2391, the brightest star between R Sct and the cluster. The two stars have a separation of 38" and magnitudes of 6.5 and 9.5.
This is a circumpolar eclipsing binary, which is easy to find and bright enough to watch in binoculars. Usually shining at magnitude 6.2, RZ dips by 1.5 magnitudes almost once a day, when an unseen companion passes in front of it.
Observing eclipsing binaries is quite different from observing other variables. Single observations are useless; instead, one makes a number of observations over a couple of hours during the time of a predicted eclipse. To watch RZ Cas's entire eclipse, begin estimating its brightness about 2 hours before the eclipse minimum is due and make estimates every 10 minutes or so throughout the eclipse.
Like many other eclipsing binaries, RZ Cas undergoes slight, unpredictable changes in its period, and new eclipse timings are always needed to keep track of this behaviour.
Finder charts for both variables accompany this article and I can provide detailed charts and predicted
eclipse times for RZ Cas. See me at a meeting or call me at 829-7514.
DEEP SKY WEEKEND THIS MONTH
As mentioned in several places in this issue, the weekend of September 21-23 is the 12th annual Ottawa Centre Deep Sky Weekend, This is an all-weekend star night, held at IRO, open to everyone. The invitation is especially open to those of our members who have not had the opportunity to see our site, and members of other centres who would like to see it. Members may camp at IRO, but there are no facilities. Bring your own food and water. Most people, though, will probably just come for the night, and observe many marvellous objects under the beautiful clear fall skies. One of the 3 nights is bound to be clear. The weekend is usually held in October, so having it in September should make for a warmer night.
See you out there!
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OTTAWA CENTRE R.A.S.C.
LIST OF KEYHOLDERS, INDIAN RIVER OBSERVATORY JULY 1984
NAME PHONE NO
Brian Stokoe 731-3174
Louis Krushnisky 731-8409
Brian Burke 521-8856
Frank Roy 820-0874
Sandra Thuesen 829-7514
Rolf Meier 820-5784
Simon Tsang 226-3740
Gary Susick 836-2451
Malcolm Lambourne 729-8112
Fred Lossing 733-2715
Ted Bean 224-7318
Doug George 224-3611
Robin Molson 225-3082
Bill Dey 737-0518