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Sunday, August 30, 2009

Hazy but happy

The monthly observing session with my astronomy club up in the West Virginia mountains last weekend was a bit of a disappointment due to clouds and haze. Even the night that was mostly clear just didn't live up to the potential of that dark site. Still, a few of us eked out some decent observations.

I'm not sure how I missed it all these years, but one observer mentioned the globular cluster in M7. Well, it's not really in M7 or even along the line of sight, but it is quite close (the small fuzzy spot about halfway to the right edge and slightly above center in the linked image). That's NGC 6453, a 9.9 mag globular about half a degree to the WNW of the center of M7. In the 10-inch, I really couldn't get resolution, but it did appear a bit grainy, giving the distinct impression of being made up of stars and not gas or dust.

I was up there for three nights. The first night there was some clearing, but it was very hazy. So I spent quite a bit of time on Jupiter. I've gotten to the point where on a night of good seeing, I can correctly identify the four Galilean moons based on size and brightness (as can be seen in this animation of Europa occulting Ganymede back in May 2008)- maybe even a hint of color differences. So we watched a partial eclipse involving Io and Ganymede. I was able to push the power up to 312x, which is the maximum with my Baader Hyperion zoom coupled with a 2x barlow, and which is rarely productive in the generally poor seeing in this area of the world. A couple of years ago I made a mask to stop down the aperture from 10 inches to about 3-3/4 inches with an off-axis hole in a piece of foam board laminated with clear contact paper for dew resistance. (Boy, do we need that around here! We had dew of Biblical proportions on the third night.) You see, I really was missing the sharp details of my Tasco 4.5-inch. This really creates a second planetary and double-star scope. Not only is Jupiter dimmed down to a more manageable brightness, but it sharpens up immensely. I just fasten it over the aperture with three Velcro pieces. So I got some good detail on the cloud bands. And there's something just really satisfying to see those moons as little sharply defined balls. Same with Neptune, which was relatively close, a little further to the NE but still in Capricornus.

The same observer also hunted for several of the comets usually visible at any given time. I did have Comet Christensen (C/2006 W3) plugged into my software chart, and it was an easy find in Sagitta. I guess it was about magnitude 8.5. A nice sized fuzzball with a well-defined inner coma. No tail that I could see through the haze, although at that altitude the transparency was a lot better than down low, where the soup pretty much swallowed Sagittarius and Scorpius early in the night along with all those nice Milky Way objects we were hoping to ogle.

The second night was pretty much clouded out, but on the third night I hunted for several faint planetaries, finding a few but also unable to spot some others. I didn't even try for Gyulbudaghian's Nebula (GM1-2 in Cepheus), one of my favorite challenge objects lately, since I haven't definitively spotted it in the 10-inch from that location (or any other) even on very transparent nights. But someday I will see it in the 10. I know it exists since I've seen it in a 30-inch. Speaking of which, one observer had his 30-inch set up nearby, and I didn't even take a peek through it. Is that stupid, or what? But I get so into hopping from one thing to the next that before I know it, it's time to pack it in. I'm sure you know the feeling.