Io in front of Callisto's Shadow
Io in front of Callisto's Shadow

Image by Dave Nakamoto

Date :  Jan 23rd 2015
Time :  10:21pm
Location :  Griffith Observatory, front lawn
Telescope :  Orion 10-inch aperture f/4.5 Newtonian with 2x Barlow
Mount :  Orion EQ-G computerized mount
Camera :  Philips model SPC900NC web camera, 640x480
Exposure :  1/10 sec.  60 frames from a 3 minute video were stacked using Registax.

I had to fiddle with a lot of stacking parameters and filtering to bring it out, but I finally see Io in front of Callisto's shadow, forming a thin ring, visible just to the right of center.