Saturn’s 250-mile-wide icy moon Mimas shines in direct sunlight and reflected light from Saturn in this image, a composite of raw images acquired by NASA’s Cassini spacecraft on Jan. 30, 2017 and received on Earth today, Feb. 1. This is a bit of a “Frankenstein” job I made, assembled from five separate narrow-angle camera images taken in various wavelengths so the proportions are slightly off here and there, but the general placement of surface features are about right and the lighting is accurate to the scene. Mimas’ south pole is within the deeply shadowed area at the bottom; north is up.
A series of images from Cassini shows the 110-mile-wide Janus passing through shadows cast by Saturn’s rings.
Janus shares its orbit within the ring system with sister moon Epimetheus. Both are small, rocky worlds…irregularly-shaped clusters of rubble pockmarked by ancient craters and displaying lots of scrapes and gouges, evidence of glancing blows by larger bodies.