These side-by-side views of a star seen through Saturn's densely populated B ring show marked contrast between the region where spokes -- the ghostly radial features periodically seen in the B ring -- are produced and regions where no spokes are seen.

In the view at left, the ring displays an uneven grainy texture, with a great deal of variability in brightness along the direction of ring particle motion. In the view at right, the ring is far smoother and more uniform along the same longitudinal direction.

Ring scientists on the Cassini Imaging Team are studying images such as these to understand the processes by which spokes are created. This difference in appearance from one location to another on the ring could provide the researchers with helpful insights into the features' formation.

The views were acquired about half an hour apart as the Cassini spacecraft looked toward the unlit side of the rings from about 33 degrees above the ringplane.

The images were taken in visible light with the Cassini spacecraft narrow-angle camera on Sept. 26, 2006 at a distance of approximately 515,000 kilometers (320,000 miles) from Saturn and at a Sun-Saturn-spacecraft, or phase, angle of 102 degrees. Image scale is about 3 kilometers (2 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/home/index.cfm. The Cassini imaging team homepage is at http://ciclops.org.