Lake Sonoma 2/24/06

by Steve Gottlieb

On Friday, I decided to return to Lake Sonoma as the weather was looking grim for later in the weekend. Traffic was surprisingly light for a Friday, even through Santa Rosa (are folks on vacation). Arrived before sunset, set up and enjoyed the view of Mercury about 10° up in the west after sunset. The sky was broken up by bands of clouds that partially dissipated at sunset but still obscured parts of the sky. I was hopeful the skies would completely clear, but that was not the case. Before 7:00, I was joined by Chelle and Art Owens, Linda and Norman Mahan as well as Bob Berta, visiting from Michigan. By the time it was dark at 7:25, clouds had moved over much of the sky and it was looking like we'd have to poke around through sucker holes. Surprisingly, though, seeing was very good (I viewed several sub-arcsecond pairs and a couple of these are at the end of the notes) and I pumped up the magnification to 800x for some memorable deep sky views. We ended up with several stretches of clear skies, followed by bands of clouds and then clearing, etc. By 10:15 the clouds seemed to win the battle as they had completed covered the skies and we gave up at that point. Here are a few of the highlights.

NGC 1999	05 36 25.3 -06 42 57	Size 2x2
18" (2/24/06): spectacular view at 565x. The bright, mag 10.5 central star appears slightly offset east of center, though this may be an optical affect due to the Bok globule on the west side. The bright, 2' reflection nebula s slightly brighter just following the central star. The irregular dark vacuity is large and detailed at this power and appears anvil-shaped. The base of the anvil is along the western side and oriented N-S. There is a narrow extension to the south that tapers to a wedge. Along the north side, the globule extends to the east and partially wraps around the central star. This was the fist time I've seen the globule take on an appearance similar to the well-known HST image.
NGC 2022 = PK 196-10.1 = PN G196.6-10.9	05 42 06.2 +09 05 10	V = 11.7; Size 29"x28"
18" (2/24/06): at 220x appeared moderately bright, fairly small, round, ~25" diameter, very slightly elongated, irregularly lit and brighter along the western half of the rim giving a "C" appearance. A faint sparkle is occasionally visible on the WSW edge of the rim and images show this may be a faint superimposed star or knot in the planetary. Excellent view at 320x. The planetary is weakly annular with the rim a bit dimmer on the Se side. At 435x, the shape is slightly elongated SW to NE, ~27"x22" with a mottled interior and a brighter rim, particularly along the western half. The appearance is quite patchy at 565x and the sparkle on the SW end is still evident. No central star seen at any power.
NGC 2158 = Mel 40 = Cr 81	06 07 26 +24 05.8	V = 8.6; Size 5
18" (2/24/06): at 323x, this rich, irregularly shaped cluster is beautifully resolved into 45-50 stars that are peppered over a 5' background glow. Appears like a resolved globular of low concentration class. Includes a couple of dozen mag 13.5-14.5 stars along with a rich carpet of fainter mag 15 stars. There are several close pairs (1"-2" and possibly closer) and the number of stars keep increasing in moments of rock steady seeing as they seem to emerge from the background. A single brighter star is at the est edge.
NGC 2392 = Eskimo Nebula = PN G197.8+17.3	07 29 10.8 +20 54 42	V = 9.2; Size 47"x43"
18" (2/24/06): viewed at 807x in good seeing. This remarkable planetary has a darker ring around the bright, 9th magnitude central star. This is surrounded by fairly narrow bright annulus, perhaps 20" in diameter. The rim is slightly brighter along the western half and brightest along the NW section. Moving outwards, a narrow darker ring separates the inner shell from a large, lower surface brightness outer halo that extends out to nearly 1' in diameter (though the diameter is commonly listed as only 47").
NGC 2438 = PK 231+4.2 = PN G231.8+04.1	07 41 50.6 -14 44 07	V = 11.5; Size 73"x68"
18" (2/24/06): beautiful view of this 70" planetary within M46 at 323x. The annulus is quite prominent and relatively thick with a weakly glowing interior. The rim is irregularly lit and a bit weaker on the NW side and brighter on the eastern side. A mag 13 star is just NW of center (not central star, though) and a second fainter star (mag 14.5) close SW in the interior was also visible. A mag 11 star is just off the SE edge. At 807x, the rim is noticeably brighter and thicker on the eastern half than a weaker section along the NW side.
ADS 6258	07 39 46.7 +05 16 26	V = 9.2/9.5; Separation 0.8"
18" (2/24/06): viewed at 807x in steady seeing. This equal mag pair was cleanly resolved with black space between the airy discs.
STF 1126 = ADS 6263	07 40 07.0 +05 13 52	V = 6.4/6.7; Separation 0.9"
18" (2/24/06): viewed at 807x in steady seeing along with ADS 6258 just following Procyon. Cleanly resolved with black space between the bright pair of mag 6.4/6.7 stars.

Posted on sf-bay-tac Feb 25, 2006 14:59:41 PT
Converted by report.pm 1.2 Mar 02, 2006 19:38:24 PT