The tip of the shadow of the moon Tethys is cut off where it crosses Saturn's B
ring, demonstrating the variations in density across the planet's rings.
Most of Tethys' shadow is seen lying across the A ring and Cassini Division in
this view which looks toward the unilluminated side of the rings from about 50
degrees above the ringplane. The densest part of the A ring and the denser B
ring let neither sunlight nor the darkness of Tethys' shadow pass through to the
spacecraft's camera, so the moon's shadow appears cut off. The B ring appears
brightly lit here from Saturnshine. Tethys itself is not shown. See PIA11498 for
view of Tethys' shadow cut off more abruptly by the B ring.
As Saturn approaches its August 2009 equinox, the planet's moons cast shadows
onto the rings. To learn more about this special time and to see a movie of a moon's
shadow moving across the rings, see PIA11651.
The image was taken in visible light with the Cassini spacecraft wide-angle camera
on April 29, 2009. The view was acquired at a distance of approximately 1.3 million
kilometers (808,000 miles) from Saturn and at a Sun-Saturn-spacecraft, or phase,
angle of 52 degrees. Image scale is 76 kilometers (47 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.
For more information about the Cassini-Huygens mission visit
http://saturn.jpl.nasa.gov/. The Cassini imaging team
homepage is at http://ciclops.org.