January 29, 2009
The Cassini spacecraft trades recent views of dark spokes in Saturn's B ring for the bright spokes seen here.
In the viewing geometry in which Cassini is looking approximately in the direction of the sun (called high phase), the spokes appear white against the rings because the very small particles comprising the spokes preferentially scatter light forward (in this case, toward Cassini).
Dark spokes can be seen in images captured at low phase angles earlier in 2008. (See 'Tis the Season for Spokes.)
This view looks toward the sunlit side of the rings from about 21 degrees below the ringplane and was obtained at a distance of approximately 563,000 kilometers (350,000 miles) from Saturn and at a Sun-Saturn-spacecraft, or phase, angle of 151 degrees. The image was taken in visible light with the Cassini spacecraft wide-angle camera on Dec. 26, 2008. Image scale is 60 kilometers (37 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