July 20, 2009
The shadow of the moon Tethys is cast onto Saturn's A ring, almost blanketing the Enke Gap.
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 a movie of a moon's shadow moving across the rings, see Moon Shadow in Motion and Weaving a Shadow.
This view looks toward the sunlit side of the rings from about 29 degrees below the ringplane. The image was taken in visible light with the Cassini spacecraft narrow-angle camera on May 25, 2009. The view was acquired at a distance of approximately 759,000 kilometers (472,000 miles) from Saturn and at a Sun-Saturn-spacecraft, or phase, angle of 56 degrees. Image scale is 4 kilometers (3 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 mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging operations center is based at the Space Science Institute in Boulder, Colo.
Credit: NASA/JPL/Space Science Institute