CICLOPS: Cassini Imaging Central Laboratory for OPerationS

Stubby Shadow
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Saturn's small moon Pan, brightly overexposed, casts a short shadow on the A ring in this image taken before the planet's August 2009 equinox.

Pan (28 kilometers, 17 miles across) orbits in the Encke Gap of the A ring, and can be seen near the center of the image. The novel illumination geometry that accompanies equinox lowers the sun's angle to the ringplane, significantly darkens the rings, and causes out-of-plane structures to look anomalously bright and cast shadows across 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. Before and after equinox, Cassini's cameras have spotted not only the predictable shadows of some of Saturn's moons (see PIA11657), but also the shadows of newly revealed vertical structures in the rings themselves (see PIA11665).

This view looks toward the southern, sunlit side of the rings from about 58 degrees below the ringplane.

The image was taken in visible light with the Cassini spacecraft narrow-angle camera on May 9, 2009. The view was acquired at a distance of approximately 908,000 kilometers (564,000 miles) from Pan. Image scale is 5 kilometers (3 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: December 17, 2009 (PIA 11647)
Image/Caption Information
  Stubby Shadow
PIA 11647

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