Jupiter Moon Transit, January 24, 2015 (06:28 UT)
Three moons and their shadows parade across Jupiter at the start of the event at 06:28 UT on January 24, 2015. From left to right the moons Callisto and Io are above Jupiter's cloud tops. The shadows from Europa (not seen in the image), Callisto, and Io are strung out from left to right.
NASA, ESA, and the Hubble Heritage Team (STScI/AURA)