CICLOPS: Cassini Imaging Central Laboratory for OPerationS

F Ring Shepherds
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Prometheus (86 kilometers, 53 miles across) and Pandora (81 kilometers, 50 miles across) are captured here in a single image taken from less than a degree above the dark side of Saturn's rings. Pandora is on the right, and Prometheus is on the left.

The two moons are separated by about 69,000 kilometers (43,000 miles) in this view.

The F ring extending farthest to the right contains a great deal of fine icy material that is more the size of dust than the boulders thought to comprise the dense B ring. These tiny particles are particularly bright from this viewing geometry, especially at right near the ansa.

At left of center, a couple of ringlets within the Encke gap (325 kilometers, 200 miles wide) can be also be easily seen due to their fine dust-sized material. The other dark features in the rings are density waves and bending waves.

The image was taken in visible light with the narrow angle camera on February 20, 2005, when Cassini was a mean distance of 1.85 million kilometers (1.15 million miles) from the moons. The image scale is about 11 kilometers (7 miles) per pixel on both moons.

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: July 18, 2005 (PIA 07544)
Image/Caption Information
  F Ring Shepherds
PIA 07544

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