The bright crescent of Saturn's moon Dione skims along just above Saturn's ringplane as storms churn in the planet's atmosphere below. Dione is 1,118 kilometers (695 miles) across.
The spectral filter used to capture this observation is particularly sensitive to high altitude clouds above most of the methane gas in Saturn's atmosphere. Dark areas in this view are regions where light penetrates the atmosphere unimpeded by such thin, high clouds.
Notable near the upper right is the turbulent southern boundary of Saturn's bright mid-equatorial zone. Cassini measured wind speeds at the altitude of the high, bright clouds north of this boundary to be 250 to 300 meters per second (560 to 670 miles per hour).
The image was taken in visible light with the Cassini spacecraft wide-angle camera on May 5, 2005, at a distance of approximately 1.3 million kilometers (800,000 miles) from Saturn using a combination of filters sensitive to wavelengths of polarized and infrared light centered at 705 and 728 nanometers, respectively. The image scale is 74 kilometers (46 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 team is based at the Space Science Institute, Boulder, Colo.
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.