Seen within the vast expanse of Saturn's rings, Prometheus appears as little more than a dot. But that little moon still manages to shape the F ring, confining it to its narrow domain.

Prometheus (53 miles, or 86 kilometers across) and its fellow moon Pandora (50 miles, or 81 kilometers across) orbit beside the F ring and keep the ring from spreading outward through a process dubbed "shepherding."

This view looks toward the unilluminated side of the rings from about 45 degrees below the ringplane. The image was taken in green light with the Cassini spacecraft wide-angle camera on March 8, 2014.

The view was obtained at a distance of approximately 533,000 miles (858,000 kilometers) from Prometheus and at a Sun-Prometheus-spacecraft, or phase, angle of 90 degrees. Image scale is 32 miles (51 kilometers) per pixel.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. NASA's 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, Colo.

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.