CICLOPS: Cassini Imaging Central Laboratory for OPerationS
Science at the Shadow Boundary

Science at the Shadow Boundary
PIA 08825

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  Saturn's shadow cloaks the faint D ring at the bottom of this image.

Observations of the shadow boundary, like this one, enable scientists to clearly detect and measure the brightness of diffuse and faint ring features like the inner part of the D-ring. Such brightness measurements are often difficult to make, but the shadow region provides a very dark standard against which to compare the D ring, as the only brightness in the shadow is provided by the background of space.

The bright specks across the scene, both in the bright rings and in the shadow, are either stars or cosmic ray hits on the camera's detector.

This view looks toward the unlit side of the rings from about 42 degrees above the ringplane.

The image was taken in visible light with the Cassini spacecraft wide-angle camera on Nov. 12, 2006. Cassini was then at a distance of approximately 1.4 million kilometers (900,000 miles) from Saturn and at a Sun-Saturn-spacecraft, or phase, angle of 152 degrees. Image scale is 8 kilometers (5 miles) per pixel.

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 InstituteNASA/JPL/Space Science Institute
Released: December 21, 2006 (PIA 08825)
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