The little black dot on the south-west limb of Jupiter (top-right corner of the planet) is actually Ganymede’s shadow making it’s way across Jupiter’s face! According to Sky and Telescope’s online Jupiter Moon tracker, Ganymede’s shadow started to cross Jupiter around 5:30am CDT…I took my movie at 6:15am. Talk about blind luck! If you look at the image below you’ll see the same little dot down there on Jupiter’s southern hemisphere. In my image, south is up because that’s the way the telescope projects it. In Sky and Telescope’s simulation, south is down:
Update: I captured Ganymede’s shadow!