CICLOPS: Cassini Imaging Central Laboratory for OPerationS
Iapetus Spins and Tilts

Iapetus Spins and Tilts
PIA 07766

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  Saturn's two-faced moon tilts and rotates for Cassini in this mesmerizing movie sequence of images acquired during the spacecraft's close encounter with Iapetus on November 12, 2005.

The encounter begins with Cassini about 850,000 kilometers (530,000 miles) distant from Iapetus. Cassini approached over the moon's northern hemisphere, allowing for excellent full views of a 575-kilometer (360-mile) wide impact basin in northeastern Cassini Regio. Astronomer Giovanni Cassini discovered the light/dark dichotomy of Iapetus' two hemispheres (among his other Saturn discoveries), and the dark region - as well as the spacecraft - bears his name.

Also prominent in these images is a 380-kilometer (235-mile) wide basin to the northwest of the larger basin, in the transition zone between Cassini Regio and a brighter region called Roncevaux Terra, with its 150-kilometer (95-mile) wide crater Roland (at top, with a prominent central peak).

The movie takes Cassini to its closest approach, at about 415,000 kilometers (260,000 miles) from Iapetus, then looks back at the moon's receding crescent. The sequence ends with Cassini at a distance of about 460,000 kilometers (285,000 miles) from the moon.

Iapetus is 1,471 kilometers (914 miles) across.

Images taken using ultraviolet, green and infrared spectral filters in the narrow-angle camera were combined to create false-color frames for this movie. The color seen here is similar to that produced in (red, green and blue) natural color views. Resolution in the original images taken at closest approach to Iapetus was about 3 kilometers (2 miles) per pixel. The color frames were resized to create the movie.

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: December 6, 2005 (PIA 07766)
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