PeGASus Newsletter Issue #40 – Sept. 1993

  • Editorial Comments
  • Thank you
  • President’s Message
  • Electronic Messages
  • Observing at MKSP
  • The Sky
  • Where in Space
  • The NOA Workshop
  • Meetings
  • Image Gallery

Prince George Astronomical Society Executive 1993

Bob Nelson 562-2131 President: 563-6928
Alan Pretty Vice President: 562-3562
Brian Potts 565-3625 Secretary: 562-8113
David Sundberg Treasurer : 562-5774/6655
Jim Livingstone Mem. at Large 964-0155
Rod Marynovich Mem. at Large 562-0952

PeGASus Project Directors

Ted Biech 562-2131 Director: 564-2838
Orla Aaquist 562-2131 Programs 964-9626 Coordinator
Bob Nelson 562-2131 Observatory 563-6928 Director


Editorial Comments:

I do not have much to say this month, hence the large type. I am glad to see that this month’s issue contains several articles written by various members. Alan Whitman describes his experiences at the recent Mount Kobau Star Party, Chris Brougham gives directions for you to participate in an Electronic Astronomy Bulletin Board, Bob Nelson is back with the President’s Message, and some lady named Carmen Sandiego submitted an article on The Solar System. If anyone out there knows where in space Carmen Sandiego is, please let me know. I would like more of the same.


Thank you

You may have noticed recently a new addition to the observatory classroom. This is the 6″ home-made Newtonian reflector on loan to the club from Dave and Katherine Matthews. The telescope was built by Katherine’s late husband, Elmer Matthews. Katherine and Dave thought that Elmer would like the telescope to be seen and appreciated by astronomy enthusiasts. Thank you Dave and Katherine from the PGAS.


President’s Message:

It is customary for me at this time to welcome you all back. However, thanks to Ted, Orla and the PeGASus project, there was enough enthusiasm for meetings throughout the summer and it is they that might well be welcoming me back!

After the summer, we face a new year and it is time to assess what has gone before and to plan a new season. This last year, as almost everyone knows, has been extremely active for us with the completion of the telescope and observing floor, and the erection and closing-in of the classroom/meeting room addition. The place is really starting to look impressive now! This summer also marked the running of the PeGASus project which, in case you are unfamiliar with it, was the acquisition of new equipment and the running of tours throughout the summer. It is appropriate, at this time, to thank all those who have participated in these works. You know who you are and I hope that we will formally thank you by name later. This has been, and will continue to be, a team effort.

In September, I plan to get together with the executive and set goals and projects for the coming year. These could include observing projects, mirror grinding and telescope construction, the organization of volunteers for school tours and the planning for talks and activities for our meetings. Your ideas would be appreciated. In particular, we are very interested in what YOU as a member want to see happen – this is your club and please let your views be known.

We hope to rearrange the executive to reflect our new goals, drawing in capable and motivated individuals as appropriate. Please let me know if you’re interested in serving on the executive.

You don’t, however, need to be a member of the executive to help. I hope to set a number of task-specific working groups. Possible examples are the newly-formed observing group, a construction group to continue the building program, a tour group to conduct school tours, a telescope making group, and a beginners’ observing group.

Speaking of construction, we should not lose sight of the fact that the new addition to the observatory is not yet complete and there are a number of tasks we need to do before winter. The first task is to install the wiring – we hope to have this started or completed in September. Next, we have to close in the space under the eaves and frame the walls, installing insulation and drywall. We need to install a heating system so that the meeting room and indeed the whole observatory is usable in the depths of winter. The washrooms, water and sewage system will probably have to wait till spring. I’ll continue to call on our capable volunteers as usual but if you haven’t helped before, why not get involved?

The telescope and dome continue to need minor work and this will continue as time permits. The big addition (probably next year) will be digital setting circles to make finding things a lot easier. In the meantime, the telescope certainly is usable for general observing (it’s not too hard to find things once you get the knack of it). The CCD camera, an exciting addition, continues to produce excellent and/or promising images. We hope to have training sessions for those who haven’t used the big telescope and CCD camera – remember, this is your club and the facilities are here for you to use.

Also available are the club’s 20 cm Celestron, the home-built 25 cm Dobsonian and binoculars An increasing number of members have their own telescopes. On the good observing nights, it can be very enjoyable for a group of observers each with his/her telescope quietly (or not so quietly) exploring the heavens. In time, I hope that we can install a lawn on the south side of the observatory possibly with concrete pads or pillars. Why not plan to come out on the next clear night and see what is going on? If you don’t have a key, you can call the observatory number (964-3600) to find out if anyone is there. Please note, however, that this is a party line.


Electronic Messages:

An Electronic Message Area for the PGAS by Chris Brougham (chris@sloth.bc.ca).

The Prince George Free-Net Association has set up a PGAS area on their temporary home: A bulletin board called the “Hidden Hideaway.” The phone number is 563-6247 and anyone can call and read messages or leave messages of general astronomical interest. PGAS members are encouraged to post messages regarding the Society’s meetings, observatory hours, and other PGAS issues. I’ve been posting quite a few articles from two USENET newsgroups called sci.astro and alt.sci.planetary so there are things to read! Such as:

  • JPL Mission Updates
  • Pluto Fast Flyby Proposal
  • IAUC Ciculars etc.
  • How to Buy A Telescope

There is no charge for access to the Free Net area of the bulletin board. Once you’ve logged on to the board, however, you will be required to register your name and telephone number. See the July issue of Pegasus for BBS registration procedures. It’s really quite simply so don’t be afraid!

If members express enough interest in this medium of communication, it might be advantageous for the Society to consider its own BBS and astronomical file area. So if this sort of thing interests you, phone up the Hidden Hideaway and we’ll discuss it “online.”


Observing at MKSP:

Excerpts From My Observing Log

by Alan Whitman

My daughter Jennifer and I spent six nights at this year’s Mount Kobau Star Party. Four of them were all-nighters due to the superb skies (site surveys in the ’60’s identified the south Okanogan’s Mount Kobau as the finest observing site in Canada). Here are some excerpts from my observing log:

August 17-18/93 2230 – 0300

(Seeing Exceptional, Transparency Variable)

Variable conditions all night as fog and stratus formed and dissipated. But the very stable conditions and the light winds at all altitudes meant that seeing was superb, possibly the best I’ve ever experienced (see Saturn below). We were observing with John Dobson (of Dobsonian fame), John Casino (owner of the world’s largest portable telescope), Steve McAllister from Chicago and Ken Hewitt-White (he is the current MKSP president).

In John Casino’s 36″ f4.1 Dobsonian: Both of M31’s dark lanes were very prominent as was the star cloud, M32 and NGC 205 were bright – 205 was large with a bright nucleus. GC (globular cluster) M15 was bright, condensed, with a short bar of stars in the centre. The globular M13 showed its three intersecting Y-shaped dark lanes and the magnitude 12 galaxy NGC 6207 (in M13’s field) had a fair size, bright and with a nucleus. KHW introduced us to a very faint Index Catalogue galaxy halfway between M13 and NGC 6207 — it was at the edge of vision in the 36″ but is fairly visible on the photo on p. 979 of Burnham. PN (planetary nebula) M27 was bright and sprinkled with stars –the following faint area had a darker area at the outer edge of the hourglass. PN NGC 7009 (the Saturn Nebula in Aquarius) showed the faint ansae (the “rings”) as in the photo on page 191 of Burnham — the ansae were a first for me. NGC 891, the edge-on spiral in Andromeda, showed its dark lane prominently.

In McAllister’s f5 20″ Dobsonian with a Galaxy mirror: Saturn at 564X was amazing — it was crisp, clear, and HUGE at this power. Four moons, the Equatorial Zone and North Equatorial Belt, Cassini’s Division in the rings was actually a division of some width, not just a line. Then the C-ring, the crepe ring! This was an amazing experience — it wasn’t just suspected, it was clear and obvious whenever the seeing steadied and Jennifer saw it without difficulty in her first year as an observer while I had never seen it before in my 33 years as an observer. Then Ken (KHW) and I started noticing that there was a colour change at the outer edge of the A-ring, beyond where Encke’s Division would be. Later, I saw Encke’s Division itself flash into visibility for about a fifth of a second but with certainty. It was probably the finest seeing that I’ve ever experienced. Saturn was only tow days before opposition but at declination -14 degrees so it was only 27 degrees above the horizon! I expected to see the innermost C-ring sometime from some southerly latitude but never from British Columbia. It was amazing to see the “crepe ring” so clearly when I had never even suspected it ever before.

There were quite a few meteors through the night, including several telescopic ones.

August 18-19/93 2140 – 0230

(Seeing Very Good, Transparency Excellent)

GC M55 at 97x in a 10″ Dobsonian showed surprisingly good resolution for its very low altitude.

Graig McCaw’s 17.5″: GC M56 in Lyra and then the Ring Nebula at 400x with the 15th magnitude central star occasionally visible. We spent a long time on the Veil Nebula — both arcs and the much fainter triangular area between them and also other small patches using a nebular filter. There was fabulous detail in the more complex arc and in the triangle stretching through field after field. The brighter arc was visible in 7×50 binoculars (as it frequently is with excellent transparency) and both arcs were visible in 11×80’s.

With the 7×50’s: the Alpha Persei association, the double Cluster, and M31 with both companions (Jennifer noticed the companions first).

The Ring Nebula in the 36″ at about 450x showing the central star but this wasn’t my best view with this telescope. August 25/90 at 420x the 36″ showed the central star, and I also briefly but definitely saw the other star inside the ring and one foreground star superimposed on the ring — all were firsts. Then in a flash of fine seeing I felt that I saw broad parallel banding in the gauzy nebulosity inside the ring as is visible on the 200″ photos on p. 1165 of Burnham. I was not looking for this parallel banding, it just flashed out. I have not read of any other report of a visual observation of this parallel banding inside the ring.

Also with the 36″, the PN NGC 40 in Cephus with the central star –attractive with the light concentrated in the outermost edge of the ring.

August 19-20/93 2150 – 0400

(Seeing Good, Transparency Excellent)

I had spoken that afternoon on the building of the PG Astronomical Observatory as one of the several speakers. Pete Kuzel’s 17.5″: Saturn with Cassini’s Division, two belts, and four moons; GC M4 resolved with the central band of stars at 100x but low; GC M22 wonderfully at 100x and 160x –elliptical with an illusion of depth; OC (open cluster) M11 stupendous with sinuous dark dust clouds in the vicinity, especially one field preceding; and the EN (emission nebula) M8 with the Lagoon and star cluster. The Andromeda Galaxy M31 with two prominent dark lanes, the star cloud, and the stellar-appearing globular cluster in the Cassiopea-like asterism near the star cloud (a globular cluster in another galaxy–M31) were visible. The Sunflower Galaxy M63, part of the Veil Nebula, the Helix Nebula nicely at 100x with a darker centre and the 13th magnitude central star (Jennifer identified the central star I’m proud to say, rather than Pete, Jim Failes, or I). WE saw the small and faint galaxy NGC 7293. M33 very nicely at 100x and 160x showing four spiral arms, the nucleus, and at least three HII regions. M33 in Triangulum was a naked eye object with averted vision.

We finished the night with the 36″: the southern galaxy NGC 253 showing lots of mottling; an unidentified southern GC very well resolved; and finished off with M42 the Orion Nebula as it rose in morning twilight. The Trapezium had blown a very obvious large hole around it, the Huyghenian region was very mauve.

Many meteors were visible again tonight. The next night we saw a fireball that looked Magnitude -2 through cloud so we estimated that it was at least magnitude -6. It was very slow moving with a train.

August 21-22/93 2140 – 0325

(Seeing Fair to Good, Transparency Superb)

The “Cat’s Eyes” at the tip of Scorpios were visible on the horizon with the naked eye.

We started on the Sagittarius, Scorpios Milky Way with Pete’s 17.5″: big and bright OC M7 at 100x and also with the naked eye but best in 7×50’s as was nearby OC M6. I swept up a little OC near Gamma SGR. Immediately preceding it was a remarkably coal-black small dust cloud. There were also a lot of winding dark lanes in the area. Transparency was superb following a cold front — Jim Failes saw the 7 degree long dark Pipe Nebula in Ophiucus with the naked eye from the peak tonight.

At 100x with an Oxygen III filter we did the various Sagittarius emission nebulae: tremendous views of the Lagoon Nebula M8 which was faint pink; a more prominently pink Trifid Nebula M20 with all the dark lanes and also the reflection nebula immediately north of the Trifid; the adjacent OC M21; and the Swan Nebula M17 with all its fainter surrounding nebulosity. The Eagle Nebula M16 had prominent dust clouds and lots of nebulosity – it was much less visible without the filter. M24 (the Little Sagittarius Star cloud with wall to wall dense stars), the embedded tiny OC NGC 6603, and the two dark Barnard dust clouds were seen. The howling wind was bitter and drove us inside for an hour.

A fine view of the Helix planetary nebula at 100x, the strange GC M30 looking cut in half with three star chains on one side and none on the other, the Pleiades with nebulosity around every bright star, the star clouds and winding dust lanes around Gamma Cygni (also evident in the 80 mm finder), the Saturn Nebula at 100x and 160x (no ansae in the 17.5″), and finished with a fine 160x view of GC M2 showing hundreds of pinprick stars and a strong central condensation.

We viewed the zodiacal band (fainter than the challenging Gegenschein) in Pisces with Jim Failes. The naked eye views of the Cassiopea Milky Way in the Zenith were superb — the intricate


Did you know that Alan Whitman, when he lived in Kelowna, founded both the Okanagan Astronomical Society (OAS) and the Mount Kobau Star Party.


The Sky:

Here I sit with the September issues of Astronomy and Sky and Telescope in front of me trying once again to condense their monthly sky calendars into a few readable paragraphs. Yes, that’s how I do it. I know, you thought that I kept all that stuff in my head didn’t you? Anyone can do it! Is there anyone out there who would like to try???????

he autumnal equinox begins on September 22. This marks the time when the day and the night are about the same length and the nights are getting longer … and colder. On the day of the equinox, the Sun rises due east and sets due west. The full Moon closest to the autumnal equinox is called the Harvest Moon. This year the Harvest Moon comes on September 30.

As the days pass into autumn, Jupiter and Mars enter the Sun’s glare at sunset. At the PGAO, they are no longer visible after sunset because of our poor view of the western horizon. Mars lingers in the early evening glare for the rest of the year, while Jupiter glides over into the morning sky by the middle of October. On November 8, Jupiter and Venus should make a beautiful pair in the morning sky with a separation of less than half of a degree. Saturn is in the southeast at sunset and is visible all night; it makes an excellent target for the telescope. Saturn is interesting to watch now that it is past opposition because the planet casts its shadow on the rings. This shadow is best seen around quadrature which occurs this year on November 16. Also, a narrow shadow of the rings, cast along the equatorial region of Saturn, should be visible in most telescopes. Venus rises shortly before the Sun and will continue to be a morning planet for the rest of this year.

As we enter autumn, the constellation Pegasus is again visible in the early evening sky. Note that with the addition of a few letters, PGAS becomes the word PeGASus. Pegasus is most easily recognized by the asterism known as The Great Square of Pegasus which contains the three brightest stars of the constellation Pegasus and the brightest star of the constellation Andromeda. To the left of the square is the Andromeda Galaxy (M31). Using binoculars, look for a faint fuzzy spot to the east just after sunset 30 to 40 degrees above the horizon.

By Orla Aaquist


Where in Space: THE SOLAR SYSTEM (Part one) by Carmen

The current scientific model for the formation of the Sun and planets holds that when the Sun condensed out of the solar nebula, it cast off a disc of rapidly spinning material that contained the material that formed the planets. This is called the “disc accretion hypothesis”. According to the disc accretion hypothesis, most of the angular momentum of the solar nebula (the spin momentum of the dust cloud) was contained in the cast off disc of dust and gas, and this disc then condensed into the planets. As a result of the shedding of the original accretion disc, the Sun contains only 0.5 percent of the angular momentum of the solar system, whereas Jupiter alone accounts for about 60 percent, and the four gas giant planets (Jupiter, Saturn, Uranus and Neptune) contain over 99 percent of the spin momentum of the solar system.

The formation of the planets from a thin disc of material also accounts for the fact that the planets are found within a few degrees of the “plane of the ecliptic”, the plane which contains the Earth’s orbit. Of the planets, only Pluto and Mercury are more than 5 degrees off the ecliptic (Pluto by 17 degrees, and Mercury by only seven). Moreover, all of the planets move in the same direction around the Sun,and all but Venus and Uranus rotate in the same direction as well.

The proximity to the early Sun obviously had profound effects on the nature of each planet that was formed. The four nearest the Sun are know as the “inner planets,” (Mercury, Venus, Earth,and Mars). All four inner planets are relatively dense bodies of rock with nickel iron cores. Of the inner planets, only the Earth has a moon of appreciable size (Phobos and Deimos, the moons of Mars, may well be captured asteroids), and three (Earth, Venus, and Mars) have atmospheres, containing oxygen in the case of Earth and carbon dioxide in the case of Mars and Venus.

Immediately beyond the inner planets lies the asteroid belt, a region of small rock and metal bodies that may look somewhat like the entire solar system did before the planets formed. In the case of the asteroid belt, the density of planetesimals may too low to allow a planet to form, and the gravitational influence of Jupiter may have hindered the process, perhaps by “gobbling up” material that might other have formed a fifth inner planet.

Jupiter is the first of the “gas giants” which contain most of the solar system planetary mass. Not only do Jupiter, Saturn, Uranus, and Neptune contain most of the angular momentum of the solar system, they also contain the vast majority of the planetary mass (well over 99 percent). At distances from the Sun of greater than 5 A.U (A.U = Astronomical Unit, the mean distance from the Earth to the Sun), solar radiation is low enough to allow the planetary capture of atmospheres containing hydrogen and helium, and these elements make up most of the composition of the gas giants. The gas giants are massive, despite their gaseous composition, and each has a set of moons, some of which are as large as a small planet (like Mercury). One such moon, Titan, which orbits Saturn, has a substantial atmosphere.

In addition to the asteroids, there are other oddball members of the solar system. The planet Pluto with its large moon Charon, is one such oddball, being much farther out of the plane of the ecliptic than the rest of the planets. Pluto has as eccentric orbit besides. While the rest of the planets have nearly circular orbits (low eccentricity), that of Pluto is sufficiently elongated to occasionally venture inside the orbit of Neptune (such is the case now, in fact, and it will remain so until 1999).

The comets are other oddball members of the solar system, since cometary orbits are often very eccentric, out of the plane of the ecliptic, and sometimes retrograde (they sometimes orbit in the opposite direction to the planets). Often little more than large flying snowballs, on occasion comets can be the most spectacular sights in the night sky.


The NOA Workshop:

At the last meeting of the PGAS it was suggested that a series of workshop for new members be organized to help them get acquainted with the sky, the observatory, and the methods of astronomy. Vince Hogan and myself will have started such a workshop probably before you receive this newsletter. The intended workshop participants are PGAO members who are new to observing and astronomy, and I will henceforth refer to the workshops as The New Observers to Astronomy workshops or NOA for short. As I am writing these words, the format of the NOA workshops are still only roughly outlined in my mind, but I think that the topics will be of the following nature:

  1. What is in the sky, and naked eye astronomy.
  2. Using star charts and star hopping.
  3. Seeing more with binoculars.
  4. Using telescopes.

The plan is to cover the four topics in four successive Monday evenings (weather permitting) and then to cycle through them again on another evening of the week, and-so-on throughout the year. Because the lessons are very informal, it is doubtful that any one series of four workshops will be the same as the previous, so members can attend the workshops as many times as they wish and get something new out of them each time.

The first series of workshops are being held on Monday evenings from 8 to 9 P.M. at the observatory, starting September 20 with an introduction of what is in the sky and naked eye astronomy. The second workshop, using star charts and star hopping, will run on September 27, and-so-on. Feel free to join the workshops at any time, and to participate for as many sessions as you wish. We hope that as NOA matures, the topics will change to suit the needs of the PGAS participants. In the next issue, I hope to keep you informed of the progress of NOA and the scheduling of the next set of workshops. If you have any suggestions or questions give me a call at 964-9626.

One final note. Please do not expect formal, prepared lessons in these workshops. The idea of the workshop setting is for all the participants to get involved learning some basic observational techniques. Vince and I will hopefully be able to gather the necessary materials to make the workshop successful and fun. If not, then we’ll do better next time around.


Meetings:

Next Meeting: The September 29th meeting will start at 7:30 P.M. at the College of New Caledonia. Come to the Physics Laboratory on the second floor by the main entrance. The room number is 2-223.

At the last meeting, many of the members expressed an interest to hold more of our meetings at the observatory. However, since colder weather is upon us, the executive felt that it would be safer to meet at the college since the observatory classroom is not yet heated. The agenda for the next meeting is approximately as follows:

  Time  Activity
 7:30 to 8:00  changing club structure, call for nominations
  8:00 to 8:20  The Harvest Moon by Bob Nelson
 8:20 to 9:00  Music of the Spheres by Orla Aaquist
 9:00 to 10:00  coffee and chats

The monthly meeting is a time for all members to get together. We hope to make these meetings entertaining to all. If you want to contribute something to these meetings, please let someone on the executive know so that we can include your contribution in the agenda or this newsletter.

Last Meeting: The last meeting was held at the observatory on Tedford Road. At that meeting, current procedures for the operation of the observatory and the use of the various equipment was described briefly. Several members volunteered to serve on the observer’s group which were to suggest general operation procedures of the observatory and equipment. These people were Alan Whitman, Brian Potts, Ted Biech, Chris Brougham, Dave Kubert, and Drew Chrisholm.

Interest was also shown in starting a series of workshops for new members. Orla Aaquist volunteered to get such workshops underway in the fall.

Terry Farnham indicated a willingness to work on the observatory sign, and Alan Whitman volunteered to etch the PGAO letters on the observatory equipment. Kelly Keener showed an interest to work on the club’s promotional video with Jon Bowen.


Image Gallery

orion_a orion_b


Prince George Astronomical Society inquiries and PeGASus correspondence may be mailed to:

PGAS College of New Caledonia 3330 – 22nd Avenue Prince George, B.C. V2N 1P8

Deadline for the October issue is Friday, October 5

The Prince George Astronomical Observatory (PGAO) is located on 7365 Tedford Road The observatory phone number is 964-3600 (party line)