PIA18319: Dione Dwarfing Rhea


Dione Dwarfing Rhea

Caption:

Click here for animation of PIA18319
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Is Dione (698 miles or 1123 kilometers across) suddenly larger than Rhea (949 miles or 1527 kilometers across)? No, of course not. Cassini simply captured an image when Dione was much closer to the camera, making the moon appear much bigger than her larger sister moon.

Besides their beauty, images like these can help Cassini's navigators determine exactly where the spacecraft is and confirm that it is on course.

This view looks toward the trailing hemisphere of Dione. North on Dione is up. The image was taken in visible light with the Cassini spacecraft narrow-angle camera on April 11, 2015.

The view was obtained at a distance of approximately 68,000 miles (110,000 kilometers) from Dione and at a Sun-Dione-spacecraft, or phase, angle of 29 degrees. Image scale at Dione is 2,165 feet (660 meters) per pixel. Rhea was 300,000 miles (500,000 kilometers) away at a phase (Sun-Rhea-spacecraft) angle of 30 degrees. The image scale at Rhea is 2 miles (3 kilometers) per pixel.

Background Info:

The Cassini mission is a cooperative project of NASA, ESA (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 mission for NASA's Science Mission Directorate, Washington. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging operations center is based at the Space Science Institute in Boulder, Colorado.

For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov and http://www.nasa.gov/cassini . The Cassini imaging team homepage is at http://ciclops.org .

Cataloging Keywords:

Name Value Additional Values
Target Dione Sun
System Saturn
Target Type Satellite Sun
Mission Cassini-Huygens
Instrument Host Cassini Orbiter
Host Type Orbiter
Instrument Imaging Science Subsystem (ISS)
Detector Narrow Angle Camera
Extra Keywords Grayscale, Movie
Acquisition Date
Release Date 2015-06-01
Date in Caption 2015-04-11
Image Credit NASA/JPL-Caltech/Space Science Institute
Source photojournal.jpl.nasa.gov/catalog/PIA18319
Identifier PIA18319