CICLOPS: Cassini Imaging Central Laboratory for OPerationS
Dione's Companion

Dione's Companion
PIA 06639

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  Helene (33 kilometers, 21 miles across), seen here with Saturn's nearly edge-on rings, orbits 60 degrees ahead of Dione and is called a "Trojan" moon. The tiny moon Polydeuces (about 3 kilometers or 2 miles across and recently discovered by Cassini imaging scientists) is also a Dione Trojan, orbiting 60 degrees behind.

The image was taken in visible light with the narrow angle camera on March 12, 2005 from a distance of approximately 2 million kilometers (1.2 million miles) from Helene and at a Sun-Helene-spacecraft, or phase, angle of 90 degrees. Resolution in the original image was 10 kilometers (7 miles) per pixel.

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: May 2, 2005 (PIA 06639)
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