Saturn's icy moon Enceladus (background) slides behind Dione in this series of images shot by the Cassini spacecraft on September 8. Saturn has an entourage of more than 50 known moons, some of which share orbits around the giant planet. Enceladus and Dione are among the larger moons, however, so they don't have to share their orbital paths with any others. [NASA/JPL/SSI]