Details in the Dark

This view shows one of the huge impact basins on the terminator of Saturn's moon Iapetus and a
smaller, but still fairly large, crater near the southern bright-dark boundary. Just visible near the western limb, in the dark territory of Cassini Regio, is the moon's mysterious equatorial ridge.
The ridge was discovered in Cassini images (see Encountering Iapetus) and reaches 20 kilometers (12
miles) high in places.

This view shows principally the leading hemisphere on Iapetus. North is up and tilted 15 degrees
to the right. Iapetus is 1,468 kilometers (912 miles) across.

The image was taken with the Cassini spacecraft narrow-angle camera on March 19, 2005,
through spectral filters sensitive to wavelengths of infrared light centered at 752 nanometers. The
view was acquired at a distance of approximately 1.4 million kilometers (880,000 miles) from
Iapetus and at a Sun-Iapetus-spacecraft, or phase, angle of 70 degrees. Resolution in the original
image was 8 kilometers (5 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 team is based at the Space Science Institute,
Boulder, Colo.

For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov . For
additional images visit the Cassini imaging team homepage http://ciclops.org .

Credit: NASA/JPL/Space Science Institute