This movie sequence from Cassini shows dark drapes in the inner strands of
Saturn's F ring caused by the gravitational influence of the shepherd moon
Prometheus (102 kilometers, or 63 miles across).
Prometheus appears first in the sequence, interior to the F ring, and
Pandora (84 kilometers, or 52 miles across) follows along outside of the
ring. Radial structure in the bright core of the ring is visible
throughout the movie.
Prometheus orbits closer to Saturn, and thus faster, than the icy
particles that make up the F ring. The moon passes closest to the ring at
"apoapse," when it is farthest from Saturn. It is during these apoapse
passages that Prometheus has its greatest influence on the fine ring
material. With time, the ring material previously affected falls behind
so that on the next apoapse passage of Prometheus, a new gore in the inner
ring material is made. The material closer to Prometheus orbits the planet
faster than the material closer to the bright F ring core. The gores,
together with the sheared-out material, create the dark, diagonal drapes.
Several background stars are seen moving across the field during the movie.
The images in this sequence were acquired on April 13, 2005, at a distance
of approximately 1.2 million kilometers (700,000 miles) from Saturn. The
images were obtained in visible light using the Cassini spacecraft
narrow-angle camera.
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 was designed, developed and assembled at JPL.
For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov.
For additional images visit the Cassini imaging team homepage http://ciclops.org.
