Cassini crosses Saturn's ring plane, February 4, 2007
Twice each orbit, Cassini crosses through the plane of Saturn's rings. This crossing, on February 4, 2007, was from the south to the north, from the lit to the unlit side of the rings. The animation, presented in approximately true color, shows how the rings are (unsurprisingly) much darker when viewed from their unlit side than when viewed from the lit side.
The most opaque ring, the B ring, which casts the broadest, blackest shadow across the northern face of Saturn, changes most in brightness from lit to unlit side, while the much more transparent C ring, located closer to Saturn than the B ring (and which casts the thin groove-like shadows across Saturn's near-equatorial regions) changes very little in appearance as Saturn crosses the plane. This 11-frame animation was created from frames taken by Cassini's wide-angle camera through red, green, and blue filters; the frames are 20 minutes apart, so the whole animation spans two hours and 40 minutes. During that time, Saturn rotates nearly a quarter turn, which can be seen in the motions of clouds in the northern latitudes. At the very end of the animation, a bright dot -- the moon Enceladus -- appears on the far side of Saturn's rings. In the full-resolution version of the animation (GIF format, 3.2 MB), Epimetheus is also visible, running ahead of, and faster than, Enceladus.