Change of Season

Seasonal twilight is approaching for Saturn's south polar vortex -- the giant hurricane-like storm swirling around the planet's southern pole.

When the Cassini spacecraft arrived at Saturn in mid-2004, summer was ending in the southern hemisphere and most of the polar region south of 60 degrees latitude was in sunlight (see Southern Storms and Streaks). In the intervening years, Saturn has moved along in its 29-year orbit, and the Sun's rays have moved farther north. This seasonal change will eventually bring darkness to the southern poles of Saturn and its moons, but it will also bring their northern poles into the light.

The image was taken with the Cassini spacecraft wide-angle camera on Aug. 27, 2008 using a spectral filter sensitive to wavelengths of infrared light centered at 752 nanometers. The view was acquired at a distance of approximately 542,000 kilometers (337,000 miles) from Saturn. Image scale is 29 kilometers (18 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