PIA11613: Post-Equinox Color


Post-Equinox Color

Caption:

The Cassini spacecraft captured this natural color view of Saturn almost a month after the planet's August 2009 equinox. The shadow cast on the planet by the rings remains narrow.

Spokes are visible on the B ring. To learn more about these ghostly radial structures, see PIA11144 .

Mimas (396 kilometers, or 246 miles across) can be seen in the lower left. Mimas and the rings have been brightened relative to the planet to increase visibility.

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 10 degrees above the ringplane.

The red, green and blue images that were mosaicked together to create this view were obtained with the Cassini spacecraft wide-angle camera on Sept. 4, 2009. The view was obtained at a distance of approximately 2.7 million kilometers (1.7 million miles) from Saturn and at a Sun-Saturn-spacecraft, or phase, angle of 92 degrees. Image scale is 156 kilometers (97 miles) per pixel.

Background Info:

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 .

Cataloging Keywords:

Name Value Additional Values
Target Saturn B Ring, Mimas, Saturn Rings
System Saturn
Target Type Planet Ring, Satellite
Mission Cassini-Huygens
Instrument Host Cassini Orbiter
Host Type Orbiter
Instrument Imaging Science Subsystem (ISS)
Detector Wide Angle Camera
Extra Keywords Color, Shadow, Visual
Acquisition Date
Release Date 2009-10-30
Date in Caption
Image Credit NASA/JPL/Space Science Institute
Source photojournal.jpl.nasa.gov/catalog/PIA11613
Identifier PIA11613