Two moons that have profound impacts on the rings, Mimas and Prometheus, are seen here with the F ring.
Mimas (396 kilometers, or 246 miles across), the larger and much more distant of the moons, creates the Cassini division between the A and B rings.
Prometheus (86 kilometers, or 53 miles across), although much smaller than Mimas, is half of a duo responsible for maintaining the narrow F ring.
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.