Download PDF version:
ASTRONOTES ISSN 0048-8682
The Newsletter Magazine of the Ottawa Centre of the RASC
Vol. 23, No. 8 $5.00 a year October 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
OBSERVER'S GROUP MEETING - SEPTEMBER 7 David Lauzon
Brian Burke, filling in for chairman Gary Susick, opened the meeting at 8:25 pm with 45 people in attendance. Brian reminded members of the prompt 8 pm starting time for the meetings from now on. Membership fees are renewable for the membership year beginning on October 1, 1984. Starfest 84, put on by the North York Astronomy Club was reported to be a success. The Annual Deep Sky Weekend will be held on September 21-23 at IRO. On September 28 or 29, a joint star night between the Ottawa and Montreal Centres will take place near Alexandria, Ontario.
Brian proceeded and presented a talk on coming occultations. A favourable one will occur on November 14 and a few asteroidal occultations will occur soon too.
Frank Roy showed members a sidereal clock he constructed. The exact specs may be found in the September issue of Astronotes.
Doug George presented a talk on how to make a satellite. Doug's class notes were of textbook proportions, but he condensed his talk somewhat. Besides the work the satellite actually carries out, there are numerous systems and backup systems involved. The 6 main functions in a satellite are as follows: 1) payload, 2)
mission analysis, 3) attitude control, 4) reaction control, 5) power subsystems, and 6) structure. Each of these plays an integral part of the satellite. He quickly proceeded to describe the various kinds of orbits and the pros and cons of rocket launches versus the space shuttle. Dougs talk ended with an open discussion.
Lunar and Planetary coordinator Rolf Meier displaved a mounting for astrophotography. This instrument fits on a camera tripod and is clock driven. He continued by showing slides of what it can do.
Variable Star coordinator Sandy Thuesen was up to tell members of the variable star observing session planned during the Deep Sky Weekend.
Doug George was up once more to show members various shots taken on his C-8 and the 16-inch over the past few years.
Rolf Meier then presented a slide show of the 1984 Stellafane telescope maker's convention.
Fred Lossing commented on Starfest 84 and hoped to see more Ottawa members there next year.
Linda Meier was up to mention to members that she is going to reschedule her sun day for the near future.
Brian Burke closed the meeting at 10:25 pm when people were invited for refreshments.
* * *
CENTRE MEETING - SEPTEMBER 18 Malcolm Lambourne
Dr. Alister V. Jones, of the Herzberg Institute of Astrophysics, National Research Council, spoke on the subject of the CANOPUS program (Canadian Auroral Network for Open Program Unified Study). About 25 persons attended, with a high proportion of non-members.
Modern auroral research began during the International Geophysical Year of 1957-58, when a network of all-sky cameras across Canada made the first measurements of the extent and distribution of a typical auroral storm. This was found to be not central on the North Magnetic Pole, as had long been assumed, but eccentric, biassed away from the sun, with additional activity on the early morning (eastern) side.
Later work used the radar-reflecting properties of auroras to measure velocities (using Doppler shift) of ionospheric currents, from which electric field strengths could be deduced.
Magnetometers were also used to measure disturbances in the earth's magnetic field, produced by these same currents.
More recently, satellites have provided an ever-improving picture of auroral activity. Whole-aurora pictures, movies of auroras, and even daylight pictures are now possible.
From this data, and the information collected by associated satellites probing the earths magnetosphere, scientists now have an improved understanding of a typical auroral storm. Activity on the suns surface, especially flares, ejects bursts of proton-electron plasma, which arrive one to two days later in the vicinity of the earth. Constrained to move along the lines of the earths magnetic field, the particles of the plasma enter the atmosphere, where their kinetic energies are dissipated in the form of auroral emissions.
The solar plasma also distorts the earth's magnetic field, compressing it on the sunward side, and extending it into a "magnetic tail" on the night side of the planet. A shock wave also exists where the solar plasma meets the magnetosphere. Distortion of the field creates zones or "pockets" in which the plasma becomes trapped. There is evidence also of an interchange of material between the upper ionosphere and these plasma pockets.
A new program, ISTPP (International Solar Terrestrial Physics Program) will attempt to improve further our understanding of auroras, by making simultaneous observations of several aspects. Satellites launched by Sweden, USA, ESA, and Japan will make measurements in the polar, equatorial, tail, and nose regions of the magnetosphere, and in the plasma stream at the sunward side of the earth.
The Canadian contribution to ISTPP is CANOPUS. This will consist of a network of remote stations across northern Canada, concentrating on three areas of measurement:
a) Ionospheric currents, using magnetometers and ground-current sensors.
b) Ionospheric electric fields, using 50 MHz radar.
c) Proton current densities, using photometers which will scan the aurora and measure the intensities of 8 specific emission lines.
All of the Canadian equipment will be ground-based. Data from the instruments will be returned to the H.I.A. for analysis. The results will be forwarded to the ISTPP centre in the U.S.
Dr. Jones, a graduate of Cambridge University, England, has been involved in auroral and airglow research at the Herzberg Institute since 1968.
* * *
COUNCIL MEETING - SEPTEMBER 12
Council met on Wednesday, September 12 at NRC, 100
Sussex Drive. Among the items discussed were the following.
Centre membership now stands at 181, including 34 life and 16 youth members.
Quiet Site keyholders now include Sandy Thuesen.
Work on the installation of new siding on the IRO clubhouse is now essentially complete, and was done within budget. The excess material will be used to build a new outhouse this fall.
The housing for the new 10-inch telescope at IRO is now complete. This was also done well within budget, thanks to a change in design and the donation of some material by members.
A borrowed 2-inch focusser had been tried on the 16-inch at IRO as was found to be unsatisfactory. Council decided that the expert advice of Fred Lossing and Ted Bean should be sought before purchase of the item.
Committees of Council were asked to prepare budgets for the 1985 year.
The centre has 2 insurance policies covering equipment and liability. Council decided that these should be consolidated into one, providing the same coverage at a saving of about $70 per year.
The Observers Group reported two recent successful star parties, at D. Aubrey Moodie Intermediate School in July, and at IRO in August. A request for funding of $50 for coffee and cookies at future star parties was turned down; council felt that this could be supported by donations.
Frank Roy volunteered to take over the Centres computerized file of addresses, and will work out a new system with the help of Art Fraser and Rob MacCallum.
Malcolm Lambourne offered to act as recorder until year-end.
Council noted that Stan Mott is once again operating as Centre Librarian.
The Annual Dinner committee reported that the dinner will be held on November 16 this year, at Algonquin College. Time, cost, and main speaker will be announced later. Linda Meier and Sandy Thuesen join Rob MacCallum on this committee.
A questionnaire to members on centre activities is in preparation, and will be submitted to council shortly.
ANNUAL DINNER MEETING
November 16 Algonquin College
Further details will be provided to members via mailings, in Astronotes, and at coming meetings.
11TH ANNUAL DEEP SKY WEEKEND
As per tradition, this years Deep Sky Weekend was blessed with one marvelous, crystal clear (though cold) night. This was the Friday night, September 21.
Many members brought out their telescopes, with many C-8s in evidence, a Cll, and a 17.5-inch. In addition, the Centres 16-inch and newly-opened 10-inch provided some splendid views.
One of the first sights to be viewed was Comet Meier, 1984o, discovered only 4 nights earlier at IRO. Unfortunately, this faint comet needed all the clear skies that could be provided, and yielded an unspectacular sight. This was Meiers 4th discovery.
As the night progressed, many fine deep sky objects were put on view. This year, for the first time, the so-called nebular filters were in abundance. They included the Lumicon UHC and Deep Sky filters. These filters, when properly used (ie, used for the type of object for which they are designed), result in fantastic views. In effect, it is like getting a bigger telescope, and/or getting very dark skies. Objects such as the Veil Nebula in Cygnus showed detail never before seen. What a great boon to deep sky observers.
The night was a good one, which all those present will remember for a long time. For some members it was their first trek out to the land of dark skies and big telescopes. We hope that it was enjoyable for all, and we hope for an even better event next year. In the meantime, the clear, dark fall skies will be with us for a while, until they are followed with the cold skies of winter.
NEW COMET MEIER - 1984o
Rolf Meier discovered his 4th comet on the night of September 17/18, 1984, It was about 12th magnitude and low in the west at the time. Below is an ephemeris from IAU Circular 3992, for epoch 1950.0. The comet comes to perihelion on October 13, at a perihelion distance of 0.8567 AU.
Date (UT) RA DEC nag
Sept 27 14h 54.13m +5° 46.4' 11.8
Oct 2 14 47.33 +3 18.9 1
7 14 41.17 +1 09.7 11.9
12 14 35.45 -0 46.1
17 14 30.04 -2 32.2 12.1
AAVSO FALL MEETING
This will take place on October 26-28, 1984. The
location for the meeting is Salem, Massachusetts. Note that this comes very close to Halloween. Each fall, Salem sponsors a "Haunted Happenings" week and this should provide a lot of added fun to the meeting. Remember that the famous witch trials took place in Salem in 1692. The area is very historic, being one of the first settlements in the United States.
The fall meeting will have paper sessions, and a banquet, with a post-banquet talk given by Dr. Alan H. Batten, former president of the RASC, and an astronomer at the Dominion Astrophysical Observatory in Victoria, BC.
For more information, contact the AAVSO at the following address:
187 Concord Avenue
Cambridge, MA 02138
* * *
Articles for the November issue of Astronotes are due by October 19, which is 2 weeks after the October Observers Group Meeting.