Quite the show, Jupiter 10.31.12 @ 08:42 UT.
The great red spot is visible with Io and Ganymede in the shot as well. Ganymede was in transit coming in from the left and Io was passing out from behind Jupiter heading out to the top left. The dark spot is the shadow of Ganymede on Jupiter's surface.
10" F4.7 OTA
TV 5X PM + Spacers
PGR Flea 3
~ 900 / 1200 frames per channel