OR 8/27/14: Lake Sonoma
by Steve Gottlieb
Two days after new moon, I met Dennis Beckley at Lake Sonoma on Wednesday night last month (8/27/14). Unfortunately, there was no way to escape the commute traffic up 101 midweek, and as expected it was quite slow from Rohnert Park to Santa Rosa. Once I arrived at Lake Sonoma, Dennis was already there setting up, the sky was perfectly clear and soon a very thin crescent moon was just visible, very low in the west. We had a very pleasant, quiet evening -- it was fairly warm, no wind or clouds, good seeing and reasonably dark (no SQM readings). All in all, much better conditions than predicted on Clear Sky Clock. I was planning to mainly observe eye candy objects, but spent most of the time on more challenging fare, as I discovered I could go fairly deep this night with my 24-inch. Here's the rundown --
NGC 6679 appeared fairly faint to moderately bright, small, round, 18" diameter, fairly high surface brightness. A mag 14.5 star is attached at the southwest edge. MCG +11-22-056 = PGC 62026 lies just 0.6' N, and at 375x appeared extremely faint or very faint, round, just 8"-10" diameter. Once in my averted vision sweet spot, I could nearly hold this galaxy continuously. A mag 15 star (brighter than the galaxy) lies 0.3' NNE. NGC 6677 lies 1.7' SSE and appeared fairly faint, fairly small, elongated 5:2 WNW-ESE, very weak concentration, ~40"x16". A mag 14.5 star is barely off the SE end.
Immediately seen at 200x as a roundish, low surface brightness glow, ~1.5' diameter. Forms the northern vertex of a triangle with two mag 11.5/12.5 off the south side. At 260x, the surface brightness is clearly mottled and irregular and two or three superimposed stars twinkle in an out of view. At 375x, three mag 14.5-15 stars are clearly resolved in a shallow arc on the E, SE and SW sides of the halo. A couple of additional mag 15.5 stars are on the W and just N of center, for a total of a half-dozen resolved stars.
Picked up fairly easily at 260x as a faint or fairly
faint, moderately large, round glow. A quasi-stellar nucleus stands
out or perhaps a brighter superimposed star. At 375x, a mag 15-15.5
star is cleanly resolved on the east side of a very small core (less
than 30"). Occasionally 1 or 2 fainter nearby stars in the core
flicker in and out of view. The overall size was difficult to estimate,
but perhaps extended 1.5'-2'.
At 125x with OIII filter, appeared moderately bright,
fairly large, elongated 2:1 NW-SE, ~1.8'x0.9'. A mag 13 star is attached
at the SE end and the planetary appears to extend in an irregular
rectangular or oval shape to the NW. A mag 12.5 is off the NW side,
2' from the center of the PN. At 200x with NPB filter, the PN is slightly
brighter at the SE end and fades out on the NW end. Averted vision
increases the outer portion on the NW end. The mag 15 star central
star was faint, but easily visible unfiltered at 200x and 375x.
Abell 70 was viewed at 200x and 260x with and without
a NPB filter as well as 280x and 375x unfiltered. At 260x unfiltered,
Abell 70 is moderately bright, fairly small, irregularly round, 0.6'
diameter, with a slightly darker center and brighter rim, giving a
weak annular appearance. The galaxy PGC 187663 is an obvious brighter
streak along the northern rim. Adding a NPB filter, the PN improves
contrast and the galaxy is less evident (though still visible). At
375x, the galaxy dominates the view and appeared faint to fairly faint,
small, very thin 3:1 or 7:2 WNW-ESE, 20"x6", very small
bright core. Overall, the best view of both objects was unfiltered
at 280x (8mm Ethos).
Kruger 60 is an unusual binary, consisting of a pair
of red dwarfs. The period is only 44 years and the pair is currently
near its minimum separation (1.4" in 2013-2014). It was cleanly
split at 375x and the primary had an obvious orange-red color. The
companion (60B) was too faint for color. Excellent view at 500x with
the two pinpoint components widely separated. Kruger 60B, a flare
star, is one of the least massive stars known, with a mass only 0.14
x (solar mass).