Shepherd moon and flock
'Shepherd' moon Prometheus (102 kilometres across) is one of the lords of Saturn's rings. The little moon maintains the inner edge of Saturn's thin F ring, while the slightly smaller Pandora (84 kilometres) guards the ring's outer edge.
This view is a composite of nine raw images combined in a way that improves resolution and reduces noise. The final image was magnified by a factor of five.
The image clearly shows that Prometheus is not round, but instead has an oblong, potato-like shape. The moon was discovered during the US Voyager mission, and scientists then noted ridges, valleys and craters on its surface. Hints of its varied topography are present in this view, although the NASA/ESA/ASI Cassini-Huygens spacecraft will likely obtain much better images of Prometheus later in the mission.
These images were obtained with the Cassini-Huygens spacecraft wide-angle camera on 1 July 2004, around the time Cassini-Huygens entered Saturn's orbit.
The Cassini-Huygens mission is a co-operative project of NASA, ESA and ASI, the Italian space agency.
Credit: NASA/JPL/Space Science Institute