Bruce Murray Space Image Library

Mimas "rising" from behind Saturn

Mimas "rising" from behind Saturn
Mimas "rising" from behind Saturn In this 10-frame animation captured on 26 October 2007 beginning at about 17:47 UTC, Mimas appears to "rise" from behind Saturn's limb. The animation consisted of clear-filter images; they have been colorized based on one full-color set taken at the end of the sequence. NASA / JPL-Caltech / SSI / Gordan Ugarkovic

Saturn and Mimas are at extremely low phase -- the Sun is almost directly behind Cassini -- so little of Mimas' rugged topography is visible. However, there is a noticeable flat spot on Mimas' western (upper) limb, which is the rim of the giant crater Herschel. The movie also illustrates how Mimas, unusually among Saturn's inner moons, has an inclined orbit. Cassini is on the north (right), unilluminated side of Saturn's ring plane. Moons that orbit outside the rings exactly in the ring plane would appear on the left side of the rings if they were closer to Cassini than Saturn, and on the right side of the rings if they were farther from Cassini than Ssaturn. The fact that Mimas is on the left side of the rings yet is evidently behind Saturn tells you that its orbit must be tilted with respect to the ring plane.