Lake Sonoma 2/16/07

by Steve Gottlieb

NGC 281: remarkable view of this detailed emission nebula/cluster at 115x and 220x. Without a filter at 220x about three dozen stars are visible in the region of the nebula, including a number of faint stars. At the center is the multiple star Burnham 1, a striking triple with a difficult 4th component. The nebulosity responds dramatically to a UHC or OIII filter. The two brightest regions have a butterfly appearance with the two lobes or wings divided by a curving dust lane. A fainter detached portion of the southeast side. The overall dimensions extend to 15'-18'. The two lobes are fairly similar in size and surface brightness, though the following section is larger including the southern piece. The western section has the brightest and most sharply defined edge running along its southern side and oriented E-W. A long straight dust lane extends along the southern boundary of both lobes and defines the sharp edge on the western lobe. The curving central dust lane is oriented ~N-S and nearly divides the two sections, though with averted vision, faint nebulosity connects the two wings.

NGC 1579: this fairly bright reflection nebula in Perseus was viewed unfiltered at 220x. The brightest portion is a fairly striking, roundish patch, ~1.5 diameter in the center of a triangular group of 6 stars. A mag 11.5 star lies 2' N with a faint star close south. Symmetrically placed on the opposite side of the central region is a pair of mag 13 stars. A wide pair of mag 12 stars are off the NE side. Faint, irregular haze spreads out from the bright patch towards the SW, extending due west to due south and increasing the size to 6'-7', though the borders of the fainter nebosity are not well defined. There was only a hint of the dust structure visible on images.

IC 3568: at 323x without a filter this small planetary is dominated by a 6"-8" high surface brightness disc. Surrounding this well- defined disc is a much fainter, round outer halo of 15"-18". A mag 13.5 star is just off the west edge of this outer halo. With direct vision what appears to be the central star occasionally pops out in the center of the very high surface brightness glow.

Instead of suck-hole fishing, I spend some time hunting down double stars as the poor transparency didn't make much difference. Here are a few of the best -

Iota (6) Trianguli: bright colored pair with a yellow-orange primary and a pale blue secondary at 4" separation. Easily resolved at 174x.

?425: excellent well-matched white pair at 2" separation. Cleanly resolved at 220x.

5 Aurigae (O? 92): unequal mag pair with a bright mag 6 yellow primary and a much fainter mag 9.5 secondary at 4" separation. Cleanly resoved at 220x.

?644: well-matched close pair at 1.6" separation. Cleanly resolved at 220x. Both components have a pale orange color.

14 Aurigae (?653): triple star with a 5th magnitude creme primary and a wide mag 8 blue companion at 14". A third fainter mag 10.5 star is 10" from the primary.

Theta (37) Aurigae: excellent large mag contrast pair with a white 2.7-mag primary and a 7.2-mag secondary (hint of red?) at 3.5". Cleanly resolved at 220x with the fainter companion beautifully complementing the bright primary.

Steve