The ring moon Prometheus continues its work shaping the delicate F ring as Dione looks on. It is easy to see how Prometheus (86 kilometers, 53 miles across) has an irregular, oblong shape, while Dione (1,123 kilometers, 698 miles across) is quite round.
The rings are partly cut off by Saturn's shadow at right.
The image was taken in visible light with the Cassini spacecraft narrow-angle camera on Dec. 20, 2005, at a distance of approximately 2.5 million kilometers (1.6 million miles) from Dione and 2.2 million kilometers (1.4 million miles) from Prometheus. The image scale is 15 kilometers (9 miles) per pixel on Dione and 13 kilometers (8 miles) per pixel on Prometheus.
The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini-Huygens mission for NASA's Science Mission Directorate, Washington, D.C. The imaging team consists of scientists from the US, England, France, and Germany. The imaging operations center and team lead (Dr. C. Porco) are based at the Space Science Institute in Boulder, Colo.