CICLOPS: Cassini Imaging Central Laboratory for OPerationS
Tirawa at Twilight

Tirawa at Twilight
PIA 07575

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  The giant Tirawa impact basin (360 kilometers or 220 miles across) straddles the day/night boundary on Rhea in this view. The ancient basin is 5 kilometers (3 miles) deep in places, as measured in Voyager images.

The prominent bright splotch to the southeast of Tirawa is ejecta from a fairly fresh crater. This feature can be seen at much higher resolution in PIA06648.

This view of Rhea (1,528 kilometers, 949 miles across) reveals terrain slightly to the east of a similar Cassini view, released earlier (see PIA07539). The sunlit surface in this view is principally on the leading hemisphere of Rhea. North is up and rotated 13 degrees to the left.

The image was taken in visible light with the narrow angle camera on August 13, 2005, from a distance of approximately 2 million kilometers (1.2 million miles) from Rhea and at a Sun-Rhea-spacecraft, or phase, angle of 50 degrees. Resolution in the original image was 12 kilometers (7 miles) per pixel. The image has been contrast-enhanced and magnified by a factor of two to aid visibility.

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: August 30, 2005 (PIA 07575)
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