CICLOPS: Cassini Imaging Central Laboratory for OPerationS
The Transition Zone

The Transition Zone
PIA 08380

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  Soaring above the alien, icy wastelands of Iapetus, the Cassini spacecraft captured a series of high-resolution images of the transition region from dark to bright terrain at southern middle latitudes that have been mosaicked together in this view.

An important characteristic of the terrain in the boundary region is that the isolated bright patches are mainly found on slopes facing toward the bright trailing hemisphere or toward the south pole. The same polarity is found within the bright terrain, where the dark material can be seen at the bottom of craters and on equator-facing slopes. These indicate that thermal effects are at play in painting the surface of Iapetus (1,471 kilometers, 914 miles across).

The mosaic consists of eight image footprints across the surface of Iapetus. The view is centered on terrain near 38.6 degrees south latitude, 171.3 degrees west longitude. Image scale is approximately 52 meters (171 feet) per pixel.

The clear spectral filter images in this mosaic were obtained with the Cassini spacecraft narrow angle camera on Sept. 10, 2007 at a distance of approximately 5,000 kilometers (3,100 miles) from Iapetus.

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 Cassini-Huygens mission for NASA's Science Mission Directorate, Washington, D.C. The imaging team consists of scientists from the US, England, France, and Germany. The imaging operations center and team lead (Dr. C. Porco) are based at the Space Science Institute in Boulder, Colo.

For more information about the Cassini-Huygens mission, visit and the Cassini imaging team home page,

Credit: NASA/JPL/Space Science Institute
Released: October 8, 2007 (PIA 08380)
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