Masked by Methane

Saturn's rings create a brilliant halo around the turbulent giant planet. Here, the Cassini spacecraft looks into Saturn's clouds using a spectral filter sensitive to absorption by methane. Light that reaches down to depths where methane is prevalent gets absorbed. Regions of the planet devoid of the clouds and hazes that can reflect this light back to the camera appear relatively dark. Thus, the bright areas in these images represent hazes and clouds high in the atmosphere.

Because the range of wavelengths for this filter is narrow, and because most of this light is absorbed by Saturn, the planet's disk is inherently faint and the exposures required are rather long. The rings do not strongly absorb at these wavelengths, and so they reflect more light and are overexposed compared to the atmosphere.

This view looks toward the sunlit side of the rings from about 6 degrees below the ringplane. Janus (181 kilometers, or 113 miles across) is seen above the rings at right.

The image was taken with the Cassini spacecraft wide-angle camera on Sept. 25, 2007 using a spectral filter sensitive to wavelengths of infrared light centered at 890 nanometers. The view was obtained at a distance of approximately 2.3 million kilometers (1.4 million miles) from Saturn and at a Sun-Saturn-spacecraft, or phase, angle of 67 degrees. Image scale is 132 kilometers (82 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/home/index.cfm. The Cassini imaging team homepage is at http://ciclops.org.