Wednesday, September 15, 2010

Atlas and F-Ring Shadows


Delicate shadows are cast outward from Saturn's thin F ring in the lower left of this image taken as the planet approached its August 2009 equinox.

The moon Atlas (30 kilometers, or 19 miles across) is seen just above the center of the image between the A ring and thin F ring. Several background stars are also visible.

The novel illumination geometry created around the time of Saturn's August 2009 equinox allows out-of-plane structures and 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.

This view looks toward the northern, unilluminated side of the rings from about 8 degrees above the ringplane.

The image was taken in visible light with the Cassini spacecraft narrow-angle camera on May 11, 2009. The view was obtained at a distance of approximately 1.098 million kilometers (682,000 miles) from Atlas. Image scale is 7 kilometers (4 miles) per pixel.

Photo credit: NASA/JPL/Space Science Institute

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