Erich Karkoschka of the UA's Lunar and Planetary Laboratory combined a series of images taken with the Wide Field Planetary Camera 2 aboard NASA's Hubble Space Telescope to make the 18-second movie that shows Ganymede ducking behind Jupiter. . The 540 movie frames were created from Hubble images taken over a two-hour period on April 9, 2007.[credit, NASA, ESA and Erich Karkoschka - University of Arizona]
Back in the early '80s I worked on the first Voyager images of Ganymede while a grad student and continue to be fascinated by this icy Jovian satellite.