The bright crescent of Dione (1,123 kilometers, 698 miles across) skims along, just above Saturn's ringplane, as tempests turn in the planet's atmosphere below.
The spectral filter used to capture this observation is particularly sensitive to high altitude clouds which are 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 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, at the equator, to be 250 to 300 meters per second (560 to 670 miles per hour).
The image was taken in visible light with the wide angle camera on May 5, 2005, from 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.
[Caption updated on October 4, 2005.]
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 Cassini-Huygens mission for NASA's Science Mission Directorate, Washington, D.C. The imaging team consists of scientists from the US, England, France, and Germany. The imaging operations center and team lead (Dr. C. Porco) are based at the Space Science Institute in Boulder, Colo.