CICLOPS: Cassini Imaging Central Laboratory for OPerationS
Bright Duo

The moon Prometheus and a bit of Saturn's northern hemisphere are both brilliantly lit by the sun here, making the A ring seem dim in comparison.

The bright limb of Saturn's northern hemisphere can be seen through the A ring in the lower left of the image. Prometheus (86 kilometers, 53 miles across) orbits in the Roche Division between Saturn's A and F ring.

For a similar view of Pandora, another of the F ring's shepherding moons, see PIA09899.

This view looks toward the sunlit side of the rings from about 20 degrees below the ringplane. The image was taken in red light with the Cassini spacecraft narrow-angle camera on May 25, 2009. The view was acquired at a distance of approximately 694,000 kilometers (431,000 miles) from Prometheus and at a Sun-prometheus-spacecraft, or phase, angle of 49 degrees. Image scale is 3.6 kilometers (2.2 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: July 8, 2009 (PIA 11531)
Image/Caption Information
  Bright Duo
PIA 11531

Avg Rating: 9.38/10

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Alliance Member Comments
Red_dragon (Jul 12, 2009 at 11:00 AM):
I agree. At first, it's hard to figure out the geometry, but once you do that you get a great picture. Perspective tricks of Cassini's NAC I guess...
stowaway (Jul 8, 2009 at 10:36 AM):
Took a while to figure out the viewing geometry on this one. Nice picture!