Lake Sonoma

by Steve Gottlieb

In a message dated 3/2/03, Mark Wagner writes:

Lake Sonoma had good transparency and steadiness, especially late

We were able to glimpse the gravitationally lensed Double Quasar (15' NNW of NGC 3079) in Robert Leyland's 17.5-inch (individual components V = 16.5 and V = 16.7), so the transparency was excellent.

We also looked at two massive star clusters (officially dubbed SSC's or "Super-Star Clusters") in the core of NGC 1569 = Arp 210 in my 17.5" at 380x which require both excellent transparency and seeing:

17.5" (3/1/03): at 380x this is a bright, very elongated galaxy with an unusual asymmetric appearance, situated less than 1' S of a mag 9.5 star! Extended nearly 5:2 NW-SE, 2.0'x0.8'. The bright core is offset to the NW side of the glow, with a tail extending SE, bending at a slight angle to the core. Two stellar "nuclei" are visible in good seeing. The brighter "star" is embedded with the core, possibly just slightly N of center. A second fainter "star" is close SE, near the edge of the core and is visible intermittently. These stars are actually SSC's (luminous super-star clusters) which are the most massive known type of star clusters.