Ultraviolet Revelation

This low resolution view of Tethys provides scientists with useful information about the moon's surface properties, regardless of the image's small size.

The view, which was taken using an ultraviolet spectral filter, demonstrates that the eastern terrain seen here is less reflective than the west at the short wavelengths of light sampled here. This dramatic difference in brightness is not visible in images taken through other, longer wavelength filters from similar viewing geometries.

Scientists use images taken at various wavelengths, and at different viewing and lighting angles, to tease out details about the surfaces of Saturn's moons.

This view looks toward the trailing hemisphere on the Saturn-facing side of Tethys (1,071 kilometers, or 665 miles across). North is up. Ithaca Chasma is seen here at left.

The image was taken with the Cassini spacecraft narrow-angle camera on Oct. 26, 2007 using a spectral filter sensitive to wavelengths of ultraviolet light centered at 338 nanometers. The view was obtained at a distance of approximately 1.6 million kilometers (972,000 miles) from Tethys and at a Sun-Tethys-spacecraft, or phase, angle of 16 degrees. Image scale is 9 kilometers (6 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 .

Credit: NASA/JPL/Space Science Institute