CICLOPS: Cassini Imaging Central Laboratory for OPerationS
Cutting 'Cross the C Ring

The shadow of the moon Tethys cuts across the C ring in this image taken as Saturn approaches its August 2009 equinox.

The novel illumination geometry created as Saturn approaches its August 2009 equinox allows moons orbiting in or near the plane of Saturn's equatorial rings to cast shadows onto the rings. These scenes are possible only during the few months before and after Saturn's equinox which occurs only once in about 15 Earth years. To learn more about this special time and to see movies of moons' shadows moving across the rings, see PIA11651 and PIA11660.

Saturn, although very faint, can be seen lit by ringshine on the right of the image. Stars can be seen through the rings and in the background.

This view looks toward the sunlit side of the rings from about 36 degrees below the ringplane. The image was taken in visible light with the Cassini spacecraft wide-angle camera on June 9, 2009. The view was obtained at a distance of approximately 578,000 kilometers (359,000 miles) from Saturn and at a Sun-Saturn-spacecraft, or phase, angle of 66 degrees. Image scale is 31 kilometers (19 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: August 11, 2009 (PIA 11555)
Image/Caption Information
  Cutting 'Cross the C Ring
PIA 11555

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Alliance Member Comments
Dragon_of_Luck_Mah_Jonng1971 (Aug 14, 2009 at 5:28 PM):
A side note: In this image the shadow of the moon Tethys's has reached the inner edge of the C ring.
Red_dragon (Aug 12, 2009 at 8:10 AM):
Great one. As always, looks as somebody of astronomical proportions had cut the rings with a knife of also astronomical proportions.