Saturn's Ring Spokes Reappear
25 Jul 2006
This raw Cassini wide angle image has been stretched to show a ghostly white spoke in Saturn's B ring. This is the first sighting of a spoke during Cassini's climb to higher inclined orbits and the first spoke seen by Cassini on the sunlit side of the rings.
It is also the first spoke seen at high phase angle - that is, the angle formed between the Sun, the rings and Cassini. In this geometry, the feature appears white (instead of black) against the rings because the very small particles comprising the spoke preferentially scatter light in the forward direction (i.e., toward Cassini), making the spoke brighter than the background rings.
The clear filter image was taken in visible light with the Cassini spacecraft narrow-angle camera on July 23, 2006 at a distance of approximately 692,000 kilometers (430,000 miles) from Saturn and at a Sun-Saturn-spacecraft, or phase, angle of 115 degrees. Image scale on the sky at the distance of Saturn is 38 kilometers (23 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 Cassini-Huygens mission for NASA's Science Mission Directorate, Washington, D.C. The imaging team consists of scientists from the US, England, France, and Germany. The imaging operations center and team lead (Dr. C. Porco) are based at the Space Science Institute in Boulder, Colo.
For more information about the Cassini-Huygens mission, visit http://saturn.jpl.nasa.gov and the Cassini imaging team home page, http://ciclops.org.
Credit: NASA/JPL/Space Science Institute