CICLOPS: Cassini Imaging Central Laboratory for OPerationS
Spots on Janus

This close-up look at Janus (179 kilometers, 111 miles across) reveals spots on the moon's surface which may be dark material exposed by impacts. If the dark markings within bright terrain are indeed impact features, then Janus' surface represents a contrast with that of Phoebe, where impacts have uncovered bright material beneath a darker overlying layer.

Janus is supposed by scientists to be a porous body, composed mostly of water ice.

The image was taken in visible light with the narrow angle camera on May 20, 2005 from a distance of approximately 357,000 kilometers (222,000 miles) from Janus and at a Sun-Janus-spacecraft, or phase, angle of 6 degrees. Resolution in the original image was 2 kilometers (1 mile) per pixel. The view was magnified by a factor of two and contrast-enhanced to aid visibility of the moon's surface.

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: June 27, 2005 (PIA 07529)
Image/Caption Information
  Spots on Janus
PIA 07529

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