Saturn … Four Years On
Saturn … Four Years On
December 30, 2008
As Saturn advances in its orbit toward equinox and the sun gradually moves northward on the planet, the motion of Saturn's ring shadows and the changing colors of its atmosphere continue to transform the face of Saturn as seen by Cassini.
This captivating natural color view was created from images collected shortly after Cassini began its extended Equinox Mission in July 2008. It can be contrasted with earlier images from the spacecraft's four-year prime mission that show the shadow of Saturn's rings first draped high over the planet's northern hemisphere, then shifting southward as northern summer changed to spring (see Serenity of Saturn and Sliding Shadows ). During this time, the colors of the northern hemisphere have evolved from azure blue to a multitude of muted-colored bands.
This mosaic combines 30 images -- 10 each of red, green and blue light -- taken over the course of approximately two hours as Cassini panned its wide-angle camera across the entire planet and ring system on July 23, 2008, from a southerly elevation of 6 degrees.
Six moons complete this constructed panorama: Titan (5,150 kilometers, or 3,200 miles, across), Janus (179 kilometers, or 111 miles, across), Mimas (396 kilometers, or 246 miles, across), Pandora (81 kilometers, or 50 miles, across), Epimetheus (113 kilometers, or 70 miles, across) and Enceladus (504 kilometers, or 313 miles, across).
NASA's Cassini spacecraft captured these images at a distance of approximately 1.1 million kilometers (690,000 miles) from Saturn and at a sun-Saturn-spacecraft, or phase, angle of 20 degrees. Image scale is 70 kilometers (43.6 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.
Credit: NASA/JPL/Space Science Institute