CICLOPS: Cassini Imaging Central Laboratory for OPerationS

A Shepherd's Watch
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Like a shepherd guarding his sheep, Prometheus keeps a lonely watch over the F ring.

Gravitational interactions between the ring and its shepherd moons, Prometheus (53 miles, 86 kilometers across) and Pandora, keep the F ring narrowly confined. The five small, bright dots in this image (one of them seen through the A ring) are stars.

This view looks toward the unilluminated side of the rings from about 52 degrees below the ringplane. The image was taken in visible light with the Cassini spacecraft narrow-angle camera on Jan. 15, 2013.

The view was obtained at a distance of approximately 810,000 miles (1.3 million kilometers) from Prometheus and at a Sun-Prometheus-spacecraft, or phase, angle of 110 degrees. Image scale is 5 miles (8 kilometers) per pixel.

The Cassini Solstice Mission is a joint United States and European endeavor. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter was designed, developed and assembled at JPL. 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 Solstice Mission visit, and

Credit: NASA/JPL-Caltech/Space Science Institute
Released: April 1, 2013 (PIA 14657)
Image/Caption Information
  A Shepherd's Watch
PIA 14657

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