Haven't had my 12" Dob out for a while. Drug it out tonight for a quick look at 10:45pm.....and ended up staying out until nearly 2am. The seeing started out pretty average but got better and better. At first I made the rounds of some bright objects: M27, M57, & M13.
M57 was very nice at 150x. M27 was prominent, but only the Dumbbell shape was visible. M13 was average.
I then switched to Jupiter. Initially I could only see the two main cloud bands with no detail. Io was just off the limb of the planet. I watched it begin to transit where it turned into a clear, round black dot......easily visible.
Neil stopped by about midnight, and by that time the seeing was better than I have seen it all year. Now the lesser bands were visible and there was detail and irregularities in the main bands. We tried yellow and blue filters. They did slightly enhance the contrast on the main cloud bands, but diminished the finer detail. I prefer the unfiltered view. The Great Red Spot was not in view......which is a shame. I am sure it would have been quite easily seen.
I don't often use my nebula filters (not sure why). Neil suggested we go back to M27 and M57 with an O III filter. What a difference. It noticeably increased brightness on both objects. We could now see the fainter nebulosity in M27.
Neil located NGC 6781, a very faint planetary nebula. It was totally invisible without the filter, and yet easily seen (although faint) with the O III.
Finally, we turned the scope toward the moon with a 6mm eyepiece in the focuser (250x). Tycho showed amazing details in the crater walls. The highlight was the crater Theophilus on the edge of Mare Nectaris. The detail visible was spectacular! I have never seen it better. The Straight Wall (Rupes Recta)was a fine, sharp white line....as the sun was illuminating it from the west.
By this time I was wishing I had set up my imaging gear to get some webcam video of both Jupiter and the moon, but then, I might have missed some great "live" views. I have to be up at 6:30am, and clouds were gathering......so it was time to call it a night.