Lake Sonoma 8 Oct 2005

by Matthew Marcus


I couldn't escape work last weekend, so I was especially in need of sky time yesterday, and I got a good dose. The CSCs predicted bad seeing for the first part of the night, wind light-moderate, and humidity past the red zone into brown and black by midnight. What happened was bad seeing for the first part of the night, slowly improving to 'decent', the usual Lake Sonoma Dob-Pusher wind, variable in both speed and direction, and no dew. I took the gamble of leaving my dew shield off to lower sail area and it paid off.

Doug showed up by sundown, followed by Steve Gottlieb later on. Doug and I traded lots of views. While waiting for the moon to go down, we did eye-candy and much hanging out under the stars. It's amazing how much light even a crescent moon delivers. The sky got reasonably dark once the Bright Thing left the scene.

Among the constellations I've left relatively neglected in my surveying are Draco, Aries and Cetus. I tend to neglect Draco because lots of it is way to the north, which is inconvenient for my mount, and the other two because they possess no obvious star patterns to remind me to point a scope there. I discovered that I had logged only one NSOG-described object in Aries. I went a considerable distance toward remedying this lack, logging mostly galaxies in the mag11-13 range. In Draco, I loged 6690 and 6340. After that, Doug pulled out his 1997 S&T with the finder photo of objects in M31. We both got G1 (brightest glob) and C202/C203 (M31's equivalent of the Double Cluster). In Doug's scope, G1 formed a tiny equilateral triangle with two faint stars. In mine, I could see something non-stellar at that location, so I definitely got G1 - or did I? Was the haze simply the whole triangle, unresolved (I didn't see the two stars), or was it the halo of G1? Anyone know the magnitudes of those stars? The OCs looked like two or three faint stars apiece. If I didn't know, I would have considered them foreground stars and ignored them. I wonder if the stellar points I saw were indeed very bright individual stars or chance knots of bright stars in the cluster. I think it's somewhat of an omission that these DSOs of another galaxy aren't included in NSOG, Uranometria or Herald-Bobroff. Oh, yeah, M31 itself was gorgeous, with two dark lanes visible.

Steve showed me IC10, a heavily-obscured dwarf galaxy. It looked like a faint elliptical patch of Milky Way surrounding a star. I wouldn't have been confident that I saw something real if Steve hadn't then showed me the map, so I could verify that the surrounding starfield and the size and position of the object were all correct.

Going back to logging, I hit Aries and got 972, 678, 680, 697 (but not 691, which is in the same group near 1 Ari and just as bright, which seemed odd), 871 and 877. There is a close pair of stars separated E-W, and 871 is just to the N of the W star, and 877 the same distance N of the E star, as if the galaxies were ghost images of the stars. 877 is something like mag12 (I don't have NSOG in front of me), and 871 is mag13.6. Normally, I wouldn't be able to see a galaxy that faint and normally wouldn't even try. However, since I was right there, I wenr for it anyway and did see a faint flicker of something. Steve confirmed it, so I believe it. That's the faintest non-stellar object I've ever seen in my C8. Curiously, NSOG has reports of '8-10" Scopes' seeing not only 871 but the mag14 companion of 877, which I couldn't see, This seems odd because most objects fainter than about mag10.5 don't have 8-10" reports. 1 Arietis itself is a nice tight, unequal double. I also got DoDz 1, a coarse OC, which I saw as 9 stars in a roughly rectangular area. NSOG claims 30. Maybe the fainter stars would show on a steadier night.

I wrapped up my logging in Cetus, with 337 and 255, both galaxies. 255 is less than half a degree away from the interesting-looking PN 246. 246 is involved with 4 stars, as if it were an emission nebula out of which a small OC was condensing. It didn't respond well to O3 or Hbeta filters, though UHC helped. I wonder if there's a reflection component to it, as there is in the Egg Nebula. A few minutes of Googling revealed that images tend to be either red or blue to purple, but not green as is often found for PNs, and that the central star is considered hydrogen-deficient. There was also a listing for it in a table of 'pulsating PNs'. I guess the central star is variable. Anyone know more about this object?

Of course, I looked at the Pleiades, M42 and the Running Man and finished up with Mars, which was on the meridian when I started packing up at about 0300. Mars did not show any polar caps, but did display a long dark streak which took on some shape in the rare moments when the air steadied and the wind wasn't blowing. I then left the lot to the raccoons and went home.


Posted on sf-bay-tac Oct 09, 2005 15:26:15 PT
Converted by report.pm 1.2 Mar 14, 2006 20:23:49 PT