CICLOPS: Cassini Imaging Central Laboratory for OPerationS
A Pair of Shepherds

A pair of moons, Pandora and Prometheus, continue their shepherding duties near Saturn's thin F ring.

Pandora (81 kilometers, 50 miles across) orbits outside the F ring and, with the inner shepherd moon Prometheus, helps to keep the narrow lanes of the F ring in check. The gravity of potato-shaped Prometheus (86 kilometers, 53 miles across) periodically creates the streamer-channels seen here in the F ring. See PIA08397 to learn more.

This view looks toward the northern, sunlit side of the rings from about 10 degrees above the ringplane.

The image was taken in visible light with the Cassini spacecraft narrow-angle camera on Aug. 20, 2009. The view was obtained at a distance of approximately 2.3 million kilometers (1.4 million miles) from Saturn. Image scale is 13 kilometers (8 miles) per pixel.

The Cassini Equinox 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 Equinox Mission visit, and

Credit: NASA/JPL/Space Science Institute
Released: September 28, 2009 (PIA 11589)
Image/Caption Information
  A Pair of Shepherds
PIA 11589

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Alliance Member Comments
mipsandbips (Sep 28, 2009 at 6:30 PM):
Prometheus, as captured in this image, incredibly sculpted by the
impacts into the F ring also allows for the human eye to witness
an evolving ring whose structure may be radically transformed at
some point in the distant future.
rulesfor (Sep 28, 2009 at 5:50 PM):
Isn't that Daphnis in the a-ring gap, too?
stowaway (Sep 28, 2009 at 4:24 PM):
one of the best yet...