by Robert Leyland
After a couple of weeks of poor weather, and with a break opening up, a larger than usual group gathered at Lake Sonoma, many determined to get a glimpse of Comet Ikeya-Zhang.
More than a dozen groups, with at least 20 telescopes plus an assortment of binoculars, setup before dark. A few arrived after dark, so an accurate count was difficult, it did seem like a lot of people.
We divided into two sections, one larger group at the higher end of the lot, setup to see the comet for the maximum available time, and the lower group who tended to stay later.
Jane and Mojo had their (new) 7" AP refractor, which is an awe inspiring sight as it towers over all others, firmly perched on the tall pier. I got one quick peek at Jupiter, which was very nice, and a huge smile from a very happy Mojo!
Down in Dobsonian farm country I was trying to complete my Gemini survey, while mooching a few photons with views of such diverse objects as Steve Gottlieb's Quasar, the Markarian chain with Rob, the SN in Leo (NGC 3190) with Matt and Dick. A couple of nice galaxies and "La Superba" carbon star with Norm and Linda, then later in the night Omega Centauri, and Centaurus A (the hamburger), with George.
Yes, quite a diverse group, and quite welcome distractions!
| Observer | Robert Leyland |
|---|---|
| Date | 6 Apr 2002 |
| Time | 2000-0030 PST (UT -8, or 0200-0630 7 Apr 2002 UT) |
| Location | Lake Sonoma CA, 38°43'N 123°02'W Elev ~1500 (Lone Rock Flat) |
| Weather | 15°C dropping to 6°C Temp, 75% rising to 90% Humidity |
| Seeing | LM 6, transparency 7/10, steadiness 8/10, sporadic mild breeze |
| Moon | late 3rd quarter (24 days) |
| Equipment | 17.5" F5 Dob, 5" Newtonian, 9x50 finder scope, Pentax XL EPs |
The comet was very low, having just moved past M31, but still visible in the twilight. A fairly easy find in binoculars, but a shadow of its former self, it became naked eye visible in the darkening sky just before disappearing below the WNW horizon. The tail is still strong, and shows two clear streamers leading back from the head. A halo around the head was less visible than just a week or so ago, probably due to the twilight. The best views came in binoculars and wide field of view telescopes. My little 130ST did a great job, allowing me to follow the tail back for several degrees.
Gemini
Some easy stuff to warm up, views of M35 and NGC 2158, to check collimation, and acclimatize my eyes. The larger, bright, objects are very nice in the little Orion 130ST, which I've mounted on the mirror box of my Dob. It still needs a little work to get properly aligned with the big scope, but it is fun to have a complementary view as an alternative, and the eyepiece height is quit convenient.
Many of the objects in Gemini are open clusters, first up is NGC 2129 which is an easy find, by projecting about a degree off the end of the right leg. With a nice pair of very bright stars (in the 9x50 finder these show up like beady little eyes) foremost in the cluster, fainter individual stars are easily resolved in the 5".
Between NGC 2129 and M35 lies NGC 2157, a fainter open cluster that shows as a small scattered group of stars.
Then viewing between Mu and Eta GEM is IC 443 a super nova remnant. At 100x it was visible only with an OIII filter, as an irregular diffuse patch, possibly arc shaped overall, with a more obvious J-shape leading edge. Matt Marcus described it as a sideways smile. I've viewed IC 443 before, with Steve Gottlieb, and at that time we saw some extension of the nebula, that wasn't visible tonight.
Nearby IC 444 did not make an appearance. I could easily find the small arc of stars that make up Colinder 89 (open cluster), which isn't too memorable, but the reflection nebula was not visible. Checking after the fact, Uranometria 2000 (Chart 76) has IC 444 in a different place than NSOG, so this is worth a revisit.
Matt directed me to a nearby planetary nebula Abell 12 beside Mu ORI (above Betelgeuse), and I do mean just beside it. At first glance (with an OIII filter) it looks like a round lens flare in the glare from the star! A little further study reveals a distinct disk, with mild darkening in the center, it is a very nice sight.
Back in GEM, and working in the same vein, brought up a planetary nebula Jonckheere 900. Aside from having a great name, this PN is a really good example to demonstrate the difference between PN and stars, as immediately adjacent to it is a star of comparable brightness. This provides a great contrasting object, that you can use as a focus point for studying the nebula. This wasn't an easy find, I was very lucky the first time, as I just "placed" the PN in the FOV right from the Telrad, then while showing it to Matt and Dick we bumped the telescope, and I couldn't recover it nearly as easily. Adding to the difficulty was nearby Jupiter's brightness.
More open clusters were on the menu, beginning with NGC 2234 near Gamma GEM, a large loose OC of approximately 20 stars, all of similar magnitude. Not easy to distinguish from the crowded starry backdrop. Even more difficult is NGC 2265 near Xi GEM, as it is in a very crowded area. I can't honestly say I could really distinguish it from the background, lots of stars and no real borders or contrasting shapes.
A better view is NGC 2304, between Gamma and Zeta GEM, a distinct open cluster of fainter stars, perhaps 50 to 60, separated into a vaguely L shaped pattern.
Nicer still is NGC 2266, easy to find near Epsilon GEM, a distinct OC with an nice arc of bright stars lead by the brightest in the group, over the fainter 60+ members of the cluster.
There are some galaxies in GEM, between delta and Zeta GEM lies NGC 2341 and NGC 2342, a really nice pair. At 100x the larger (2342) appears elongated towards the smaller (2341) which seems circular. They reverse roles at 160x with 2341 now looking a bit oval, and 2342 seeming more circular but dappled, and uneven. A bright field star adjacent to 2341, and an associated triangle of stars point to the pair, quite a treat amidst all the open clusters.
One more open cluster, before packing it in for the night. Betwen Epsilon and Iota GEM, NGC 2331 is a large grouping of even brightness stars, in a crowded area. However, one chain of those stars is cool. It looks like a seismic shock wave chart from an earthquake, a long zig-zag of stars. Is this the Earthquake cluster?
Now it's getting late, and the daylight savings switch over is going to cost me an hour of sleep before my Soccer game in the morning... sleep is overrated anyway :-)