Lake Sonoma Saturday 1 Feb 2003

by Matthew Marcus

It was a small group that was assembled at Grey Pine, consisting of Scheor Sherman, Steve Gottlieb and myself. We were at Grey Pine because Lone Rock was closed. The Ranger came by at sundown and explained that LR was closed due to mud and that they've started closing most of the turnouts after dark. I think he hadn't realized what goes on there in the dark.

The weather was cool, going to cold (30's? low 40's?) with low humidity. The latter meant that no dew shield was needed, which was fortunate as the wind was intermittently gusty up to maybe 15mph. It was calm most of the night, though.

In the early going, the sky was brilliantly clear, though the seeing was soft. I was pulling out 13th-magnitude galaxies fairly easily. Later, though, the East got bright and the brightness spread across the sky. No, it wasn't impending dawn - I left at 4:30AM.

The Zodiacal Light was prominent in the West, extending about halfway up the sky. It's often stated that it's best at the equinoxes, but it seemed to be pretty good now, at this random time.

I had with me two issues of S&T and the February issue of Astronomy, so I had a couple of lists to work from. I started in Lepus, with the rather pretty multiple star/asterism/sparse OC 2017. This consists of nine stars, four of them bright enough to show color. Then, of course, I went to M79. Though the seeing was mediocre, M79 still looked about as good as it ever does. The next target was the PN 2418, a small round ring.

Then we started to get serious. Steve went after an emission nebula, Sh2-308. This is in CMa. It looks like a large (1/2-deg) shell surrounding a star, and it's brigher around the edges, especially one edge. I went for it in my dinky little 8". At first, I tried the usual trick for large, faint objects, that is using the lowest possible power. That didn't work, so I went to 125x and concentrated on the brightest patch. This yielded a faint but definite (confirmed by SG) arc at the right place. It looked like an eyebrow, with the eye represented by the star.

Since it was a high-transparency, low-seeing night, I also went for some other low SB objects. Steve had gotten Sextans B, a dwarf galaxy and called me over to confirm. I then went for it and found it - barely.

Next, Barnard's Loop. This is an example of the trend wherein objects once thought to be photographic-only are being routinely sighted by observers. This is partly due to the proliferation of Big Iron, but I suspect it's also that more people are trying and being persistent about it. There's also the very important factor of the availability of O3 and Hbeta filters. Without those, forget it! Anyway, I was able to spot some of the brighter parts in binox with 2" UltraBlocks over the objectives, the Ranger with an Hbeta and a 40mm EP, and the C8 with an Ultrablock and the 55mm EP. It's a hard one to log because it's so big and fuzzy that it's hard to find a place with a sharp contrast in one field. It mostly appears as bright sky which gets darker if you move left or right. That this effect appears only with the filter in place shows that it's nebular and not just sky-crap like clouds.

Most of the night was spent on galaxies. Sextans, Crater, Corvus, and Leo were all on the menu. Also, one of the articles I was looking at was about the Abell 262 group in Andromeda. This group includes many galaxies, but only three were visible to me - the tight triangle of 208,703 and 704. I couldn't really resolve them as separate entities, but the blob of light was distinctly triangular and lumpy. Steve confirmed the lumpiness.

As a break from galaxies, I looked at Thor's Helment, aka the Duck Nebula (2359). NSOG doesn't list Thor's Helmet by that name. After seeing it through Schneor's 18", I was able to see some of the fainter stuff through mine. I'd never noticed all those wisps before! Amazing what you can see if you know to look for it. No, it wasn't averted imagination; it was real.

Other galaxies, not listed in observation or any other order:

2911+2914+2919Leo These three galaxies lie inside a 125x FOV, among a sprinkle of stars. 2919 is considerably fainter than the other two. I show 2911 as detectably elongated, with the other two as round blobs.
3521 This large tilted spiral shows a bright core and a sharp cutoff on the S side due to the dust lane. It gives a real impression of having a front and a back side.
4783/82This pair in Corvus is a contact binary. The halos appear to merge so it looks like one galaxy with two cores. The Astronomy article I was using as a list didn't mention 4782 (at least not in the table), so it was a surprise to me to see a bilobed structure. I found it described in NSOG.
3041 A large, bright ellipse in Leo, with one end anchored by a star.
3044 A large, edge-on in Sextans, nicely surrounded by stars.
3511+3513A pair in Crater. 3511 is bright and large, with a star at one end. 3513 is a fainter, smaller, circular blob.
3016, 3032,3067Leo
3672, 3887Crater Unremarkable in the 8". The sort of thing one looks at to fill out a list. Isn't this a disgustingly cavalier way of dismissing entire groups of hundreds of billions of stars? Amazing how one can get used to anything!

In between all this, there was the usual doses of eye candy. M46 and M47 were way-stations on a star-hop to one of the galaxies, so I didn't neglect to look at them.

Somewhere around 0200 or 0300 an RV pulled in with lights blazing. They stopped and turned off their lights. A woman came out, wondering what we were doing, so we gave her a little sky tour including Jupiter and Saturn. Cassini's Division wasn't showing up clearly, and only two bands were visible on Jupiter, but she was still wowed. Shneor showed her M51 and Markarian's Chain. We may have sucked another one in!

An interesting and little-known point - some nebulae, particularly M42, have parts which show up best in OIII and others which are more obvious in Hbeta. For the Orion Nebula, I found that M43 was much more prominent in Hbeta, while a streamer in the W wing of the Great Bird shows in OIII and not at all in Hbeta. I wonder if the differences are due to composition or conditions of the gas.

It might be an interesting imager project to make a bicolor composite of M42 in OIII and Hbeta. Completely false color, but could show structure not apparent in one scope view.

Shneor left at maybe 0400 and I followed by 0430. I knew I needed to work at least some today, so I couldn't do my usual all-nighter.

All in all, it was just what I needed after some serious photon starvation!