Ithaca Chasma, an enormous rift that stretches more than 1,000 kilometers (620 miles) from north to south across the face of Tethys, seemingly takes a bite out of the moon's limb in this image from the Cassini spacecraft.

The canyon runs from the shadow of night in the north, across the crater Telemachus, and on to the southern limb of the moon. (North on Tethys is up and 16 degrees to the right in this image.)

Impact craters obliterate the canyon's older tectonic features and attest to the rift's great age.

A dramatic close-up of the rift can be seen from a 2005 flyby of the moon. (See PIA07734).

The image was taken in visible light with the Cassini spacecraft narrow-angle camera on Dec. 9, 2008 at a distance of approximately 245,000 kilometers (152,000 miles) from Tethys and at a Sun-Tethys-spacecraft, or phase, angle of 84 degrees. Image scale is about 1 kilometer 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.