Jupiter with two of its moons, Europa and Io, in transit across its face and casting their shadows on it. The small black dot slightly above and to the left of center is the shadow of Europa. The other black dot to its right is Io's shadow. Europa and Io can be seen as two white dots near the right edge of Jupiter, directly to the right of their respective shadows. The great red spot is the lower half of Jupiter, south of Europa's shadow. Europa and Io weren't as easy to see earlier in the transit, but as they neared Jupiter's edge, limb darkening made them stand out.
Several movies of Jupiter's rotation are here.

A composite of about 1,000 video frames selected from 1,800 taken using a Philips ToUcam Pro through an Astro-Physics 155mm (6.1 inch) refractor at about f50 starting at 3:30 UT on March 30, 2004 from northern New Jersey through hazy, partly cloudy skies. Exposure was 1/33rd second at fifteen frames/second. The video was captured using K3CCDTools, combined using Registax, and further processed in Photoshop. ©2004