CICLOPS: Cassini Imaging Central Laboratory for OPerationS
Approaching Iapetus

The slim crescent of Iapetus looms before the Cassini spacecraft as it approaches the mysterious moon.

Iapetus (1,471 kilometers, 914 miles across), seen here in false color, is unique in its dramatic variation in brightness between the northern polar region and the middle and low latitudes. Equally prominent is the moon's equatorial ridge of towering mountains. The profile of the ridge against the darkness of space reveals that it is topped by a cratered plateau approximately 15 kilometers (9 miles) wide. Further west, the profile of the ridge changes from a long plateau to discrete peaks.

The mosaic consists of four image footprints across the surface of Iapetus and has a resolution of 489 meters (0.3 miles) per pixel.

A full resolution clear filter image was combined with half-resolution images taken with infrared, green and ultraviolet spectral filters (centered at 752, 568 and 338 nanometers, respectively) to create this full resolution false color mosaic.

The color seen in this view represents an expansion of the wavelength region of the electromagnetic spectrum visible to human eyes. The intense reddish-brown hue of the dark material is far less pronounced in true color images. The use of enhanced color makes the reddish character of the dark material more visible than it would be to the naked eye. In addition, the scene has been brightened to improve the visibility of surface features.

This view was acquired with the Cassini spacecraft narrow-angle camera on Sept. 10, 2007 at a distance of about 83,000 kilometers (51,600 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 08376)
Image/Caption Information
  Approaching Iapetus
PIA 08376

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Alliance Member Comments
Breitstar (Oct 10, 2007 at 6:22 PM):
Every new image takes me closer. Every new view leaves me needing to see more.
Every new vision makes me smile and dream. Every new feature adds to Saturns lore.
Red_dragon (Oct 9, 2007 at 1:05 AM):
Truly fantastic and alien. Images that show something (Saturn or whatever) in a crescent phase are my favourites and this one is not and exception. I tip my hat to you: another great picture from CICLOPS.