Outside the soft edge of Cassini's F ring, Epimetheus and Janus negotiate
their nearly-shared orbit. The two moons' orbits are typically about 50
kilometers (30 miles) apart, and the moons actually change orbits every
few years: one moon becoming the innermost of the pair, the other becoming
the outermost.
Epimetheus' diameter is 116 kilometers (72 miles). Janus' diameter is 181
kilometers (113 miles) across.
The image was taken in visible light with the Cassini spacecraft
narrow-angle camera on Sept. 8, 2005, at a distance of approximately 1.5
million kilometers (1 million miles) from Saturn. The image scale is
about 11 kilometers (7 miles) per pixel on the two moons.
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. The Cassini imaging team homepage is at
http://ciclops.org.