PIA09731: Moons that Share


Moons that Share

Caption:

The two moons pictured here each share their orbits with other bodies.

Dione (1,126 kilometers, or 700 miles across, at left) has two much smaller "Trojan" moons, Helene and Polydeuces (not seen here), that orbit 60 degrees in front of and behind it in its orbit. Epimetheus (116 kilometers, or 72 miles across, at right) shares its orbital path with Janus, and the two moons swap positions every few years -- one moving just a bit closer to Saturn and the other moving slightly farther away.

This view looks toward the unilluminated side of the rings from less than a degree above the ringplane.

The image was taken in visible light with the Cassini spacecraft narrow-angle camera on July 28, 2007. Cassini was approximately 2.9 million kilometers (1.8 million miles) from Saturn when it acquired this view. Image scale is 15 kilometers (9 miles) per pixel on Dione.

Background Info:

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 mission for NASA's Science Mission Directorate, Washington, D.C. 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, Colo.

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

Cataloging Keywords:

Name Value Additional Values
Target Saturn Rings Dione, Epimetheus, Helene, Janus, Polydeuces, Saturn
System Saturn
Target Type Ring Planet, Satellite
Mission Cassini-Huygens
Instrument Host Cassini Orbiter
Host Type Orbiter
Instrument Imaging Science Subsystem (ISS)
Detector Narrow Angle Camera
Extra Keywords Grayscale
Acquisition Date
Release Date 2007-09-19
Date in Caption 2007-07-28
Image Credit NASA/JPL/Space Science Institute
Source photojournal.jpl.nasa.gov/catalog/PIA09731
Identifier PIA09731