CICLOPS: Cassini Imaging Central Laboratory for OPerationS
Tethys Meets Dione

Tethys Meets Dione
PIA 07620

Avg Rating: 9.23/10

Movie 650x350:
GIF 474 KB
Quicktime 772 KB
MP4 movie 30 KB


Tethys Meets Dione
PIA 07621

Avg Rating: 10/10

Still Image 444x536:
  This brief movie sequence catches Tethys (1,062 kilometers, 660 miles across) partially occulting Dione (1,123 kilometers, 698 miles across). It shows the trailing hemispheres of both moons (terrain centered on roughly 270 degrees longitude). Some rotation is evident on Tethys during the sequence.

The still image shows the two moons again, from an opposite viewing angle, with Dione in the near field.

The difference in the surface brightnesses of the two moons is immediately apparent.

The images in the movie sequence were taken in visible light with the narrow angle camera on September 11, 2005, from a distance of 2.4 million kilometers (1.5 million miles) from Tethys and 2.6 million kilometers (1.6 million miles) from Dione. The image scale is about 15 kilometers (9 miles) per pixel on both moons.

The still image was acquired on September 16, 2005 from a distance of 2.1 million kilometers (1.3 million miles) from Dione (2.7 million kilometers (1.7 million miles) from Tethys). Resolution in the original images was 13 kilometers (8 miles) per pixel on Dione and 16 kilometers (10 miles) per pixel on Tethys. The still image was magnified by a factor of two to aid visibility of surface features.

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: November 1, 2005 (PIA 07620, 07621)
Image/Caption Information