Two dark gores in Saturn's F ring demonstrate the gravitational influence
of the shepherd moon Prometheus.
The older gore at the top of this view is at a steeper angle than the
newer addition just above and to the left of Prometheus, since the former
has sheared out over the course of an orbit: particles on the inner
(right) side of the F ring travel faster in the same amount of time than
the particles on the outer (left) side, leaving the outer particles
behind.
Prometheus (102 kilometers, or 63 miles across) is lit at left by direct
sunlight and at right by reflected light from Saturn. The bright, sunlit
portion of the moon is overexposed.
Two background stars are captured above Prometheus in this view, which
looks toward the unilluminated side of the rings from about 33 degrees
above the ringplane.
The image was taken in visible light with the Cassini spacecraft
narrow-angle camera on Jan. 1, 2008. The view was acquired at a distance
of approximately 1.5 million kilometers (956,000 miles) from Saturn and at
a Sun-Saturn-spacecraft, or phase, angle of 62 degrees. Image scale is 9
kilometers (6 miles) per pixel.
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.