PIA11641: Two Pairs
- Original Caption Released with Image:
A pair of moons and a pair of moon shadows can be seen in this Cassini
spacecraft image taken about a month and a half after Saturn's August 2009
Pan (28 kilometers, or 17 miles across) orbits in the Encke Gap of the A
ring, and it can be seen casting a shadow near the center of the image.
The moon Janus, which is not visible, is casting its shadow on the A ring
in the top right of the image. Pandora (81 kilometers, or 50 miles across)
can be seen orbiting beyond the thin F ring in the top left of the image,
but its shadow doesn't accompany it here.
The novel illumination geometry that accompanies equinox lowers the sun's
angle to the ringplane, significantly darkens the rings, and causes
out-of-plane structures to look anomalously bright and cast shadows across
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.
Before and after equinox, Cassini's cameras have spotted not only the
predictable shadows of some of Saturn's moons (see PIA11657), but also the shadows
of newly revealed vertical structures in the rings themselves (see PIA11665).
This view looks toward the northern, sunlit side of the rings from about 9
degrees above the ringplane.
The image was taken in visible light with the Cassini spacecraft
narrow-angle camera on Sept. 30, 2009. The view was acquired at a distance
of approximately 2.9 million kilometers (1.8 million miles) from Pan.
Image scale is 18 kilometers (11 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.
- Image Credit:
NASA/JPL/Space Science Institute
Image Addition Date:
Image and caption provided by the Planetary Photojournal --