The images from Cassini's Dione encounter yesterday have started coming back, and there is a really cool set of 16 pictures of Dione and Rhea. Cassini's cameras are kept locked on Dione, so if you stack them together and animate them like a flip book, Rhea appears to zip behind Dione. Pretty cool! There are three frames missing toward the end, which is why it appears to stop and start; when those images are returned I'll add them in to the animation.
NASA / JPL / SSI / animation by Emily Lakdawalla
Partial eclipse of Rhea by Dione
As Cassini zoomed toward its October 11, 2005 encounter with Dione, it caught Rhea traveling behind Dione in a 16-frame movie.