PeGASus Newsletter Issue #18 – Nov. 22, 1990

Hello, everyone!! As you can see, I am resuming the newsletter that I sent out to you before I went to Calgary last year. It seems to be a good way to keep us all in touch – I’d appreciate any comments (positive or negative) that you might have. [Contributions too, would be very welcome. What about it Chris, Jody, Dave, …?]


LAST MEETING:

We had a good meeting in October (25th) with no fewer than 13 of us present and some others unable to attend. I was impressed with the new younger members and the degree of enthusiasm shown by all. It appears that the Prince George Astronomical Society is alive and well after a year in hibernation.

We had the necessary annual general meeting (sounds impressive, eh?) with agreement (elections?) as to who should be on the executive. Without wanting to sound too formal (we’re not!!), here it is:

  • President: Bob Nelson
  • Vice Pres: Al Pretty
  • Secretary: Brian Potts
  • Treasurer: Dave Sundberg
  • Memb at Large: Jody Silver

Exec. meetings will be held to a minimum, but we need some structure.

Many other things were discussed, including:

  • Badges and/or crests were proposed and will be looked into
  • A phoning “tree” has been set up and is enclosed
  • Fees were set at $20 for those working, $10 for students
  • Sky telescopes (Vanc’r) will give 25% off for PGAS members
  • We’re applying for a casino licence and date
  • We’re looking into a security system but need power
  • Signs for the door and road were proposed

RECENT EVENTS AT TMO:

Well, five of us went up there on the Saturday after the meeting. We fixed the door so that it closes easily (one person can do the job) and cleaned up generally. Other needed work (fixing the outhouse, fixing the porch railings, repainting the building, restoring the telescope, etc will have to wait for spring.) Generally, the observatory will remain dormant for the winter, although someone will have to call by periodically to check the place, reset the mousetraps, etc.


WHAT’S GOING ON IN THE SKY:

Mars is the big feature this fall. Its opposition time (the point at which it is directly opposite the sun in the sky and therefore closest to earth) will be November 27th at 2100 hours UT (1:00 PM PST). The following is taken from the Observer’s Handbook for 1990.

“Mars is the planet that has long captivated the imagination of mankind as a possible abode of life. Although the biology experiments in the two Viking spacecraft that landed on the planet in 1976 detected no known life processes in the Martian soil samples, there are many facets of Mars that make it the most Earthlike planet in the solar system. Volcanoes, polar caps at least partially composed of water ice, and ancient channels where water once flowed are amongst the most intriguing features. Observations from Earth as well as Mars-orbiting spacecraft have disclosed winds in the Martian atmosphere that reach speeds exceeding 300 km/h and raise vast amounts of dust that can envelop the planet for weeks at a time. The dust storms were though to occur with seasonal regularity shortly after Mars passed the perihelion point of its elliptical orbit, but the Viking observations revealed more complex weather patterns.

“In many ways Mars is the most interesting planet to observe with the unaided eye. It moves rapidly among the stars – its motion can usually be detected after an interval of less than a week – and it varies in brightness over a far greater range than any other planet. Mars may be distinguished by its orange-red colour, a hue that originates with the rust-coloured dust that covers much of the planet.

“Telescopically Mars is usually is a disappointingly small featureless ochre disk except within a few months of opposition when its distance from Earth is then near minimum. If Mars is at perihelion at these times, the separation can be as little as 56 million km. Such close approaches occur at intervals of 15 to 17 years; the most recent was in 1988. At a perihelion opposition the telescopic disk of Mars is 25 seconds of arc in diameter and much detail on the planet can be distinguished with telescopes of 100 mm aperture or greater. At oppositions other than when Mars is at perihelion, the disk will be correspondingly smaller.

“Late this year Mars will pass through its final favourable opposition in the 20th century for observers in mid-northern latitudes. The planet will reach 18″ in apparent diameter compared tp 24” two years ago during the excellent opposition of September 1988. However, Mars will be 25o higher in the sky when on the meridian which should partially compensate because telescopic images are generally steadier toward the zenith, all other factors being equal.

“… Overall, this is a favourable opposition for mid-northern latitudes – inferior to 1988, but better than any other close approach since 1973 and by far the best until 2003. …

“Any good-quality telescope over 70 mm aperture should reveal surface feature on the planet near opposition, including changes in the Martian dark zones from one opposition to the next. These alterations are due to he shifting climate regimes on Mars that regionally transport vast quantities of dust, both dark and light. …”

Hopefully, many of us will get out and look at Mars soon. I had a good time viewing Mars in 1988 and have many drawings, some reproduced in the Newsletter to show for it. I always saw the south polar ice cap and usually dark features that could be correlated with observations at other times.

Other planets: Mercury is east of the sun but hard to see. Venus is on the other side of the sun, just past superior conjunction. Jupiter rises before midnight and is high in the sky by sunrise. It will be a good object to view after the new year (unless you wish to stay up to the wee hours.) Saturn is low in the southern sky at sunset and sets 4 hours later.

Other objects: Orion (and with it, the magnificent Orion nebula) is up in the late evening sky and is well placed for viewing. The Milky Way in Auriga contains many open clusters that should keep observers happy finding them. The Crab Nebula (M1) is nearby and a challenging object. Let’s get out whenever it clears next and go after these objects!


NEXT MEETING:

Wednesday, Nov 28 at 7:30 in the Physics Lab (Rm 2-223) at the College. If you have a telescope, why not bring it in and we can have a go at cleaning the optics, collimating and adjusting it plus possible making or repairing parts as necessary. This is your opportunity to get your scope in top condition! If you do not have a telescope, that doesn’t matter as you’ll be welcome to watch, kibbitz, help, (heckle?), or just generally learn and gain experience.

Also: Brian Potts suggested that we should get going on mounting my 10″ mirror, to make a club telescope that all members can borrow and use. The construction can be quite simple and it will give us something to work on in the snowy cold weather when we can’t observe! The main problem is finding a good place to work (preferably on Saturdays); I’m making inquiries – if any of you have ideas, please let me know.

See you at the meeting!

Bob Nelson, President