CICLOPS: Cassini Imaging Central Laboratory for OPerationS
Seeing Double

Seeing Double
PIA 07649

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  Two sibling moons, Rhea and Dione, pose for Cassini. Even at this distance, it is easy to see that Dione (1,123 kilometers, 698 miles across, below) appears to have been geologically active in the more recent past, compared to Rhea (1,528 kilometers, 949 miles across, above). Dione's smoother surface and linear depressions mark a contrast with Rhea's cratered mug.

Sunlit terrain seen on Rhea is on the moon's Saturn-facing hemisphere; lit terrain on Dione is on that moon's leading hemisphere. North is up.

The image was taken in visible light with the Cassini spacecraft narrow-angle camera on Nov. 1, 2005, at a distance of approximately 1.8 million kilometers (1.1 million miles) from Rhea and 1.2 million kilometers (800,000 miles) from Dione. The image scale is 11 kilometers (7 miles) per pixel on Rhea and 7 kilometers (4 miles) per pixel on Dione.

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.

For more information about the Cassini-Huygens mission, visit and the Cassini imaging team home page,

Credit: NASA/JPL/Space Science Institute
Released: December 9, 2005 (PIA 07649)
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