The moon Prometheus casts a shadow on the thin F ring marked with
streamer-channels created by the moon in this image taken as Saturn
approaches its August 2009 equinox.
The gravity of potato-shaped Prometheus (86 kilometers, or 53 miles
across) periodically creates streamer-channels in the F ring. See
PIA10461 and PIA10593 to learn more. To watch a movie of this process,
see PIA08397.
The novel illumination geometry created as Saturn approaches its August
2009 equinox allows moons orbiting in or near the plane of Saturn's
equatorial rings to cast shadows onto the rings. These scenes are possible
only during the few months before and after Saturn's equinox which occurs
only once in about 15 Earth years. To learn more about this special time
and to see movies of moons' shadows moving across the rings, see PIA11651
and PIA11660.
This view looks toward the unilluminated side of the rings from about 52
degrees above the ringplane. The image was taken in visible light with the
Cassini spacecraft narrow-angle camera on June 15, 2009. The view was
acquired at a distance of approximately 1.8 million kilometers (1.1
million miles) from Prometheus and at a Sun-Prometheus-spacecraft, or
phase, angle of 85 degrees. Image scale is 11 kilometers (7 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/. The Cassini imaging team
homepage is at http://ciclops.org.