Jupiter!
After imaging the other night (more data for the Dumbbell) I decided to turn the scope towards Jupiter. Wow, I don't think I've ever seen it so good! Seeing was excellent (in my uncalibrated opinion). The Great Red Spot was obvious as was this conspicuous dark spot near the center of Jupiter's disk. Anyway, it was a no-brainer to get out the webcam and take some frames.
The dark spot on Jupiter sure does look like a shadow from one of it's moons but according to all the calculators I consulted the only thing crossing Jupiter while I was recording was Ganymede, Jupiter's largest moon. Europa can be seen in the upper left corner of the frame. Jupiter's current apparent diameter is 48 arcminutes.
Date: 07/23/2009
Time of shot: ~11:00 UTC
Scope: C9.25 with 2x barlow (approx. 4700mm EFL)
Mount: CGEM
Cam: Philips SPC900NC
Other info: ~1000 frames registered and stacked in Registax v5, additional processing in Photoshop CS4. Shutter speed was 1/50s and gain was set to ~40%.