This montage of four images of Saturn's knotted F ring shows different locations around the ring, even though all taken within a few hours of each other. There is considerable variation in the structure of the ring at these four locations.

For example, the number of ring strands differs from image to image. And in some images, kinks are clearly visible in the ring, while others regions appear more smooth.

Astronomers believe that the structure of Saturn's F ring is governed by its shepherding moons, Prometheus (102 kilometers, or 63 miles across) and Pandora (84 kilometers, or 52 miles across). The ring's appearance is expected to vary depending on how recently a ring section has encountered each moon and how close the moon came to the ring.

These images were taken in visible light with the Cassini spacecraft narrow-angle camera on May 3 and 4, 2005, from below the ringplane and at distances ranging from 735,000 to 952,000 kilometers (457,000 to 592,000 miles) from Saturn. The image scale ranges from 4 to 6 kilometers (2 to 4 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 team is based at the Space Science Institute, Boulder, Colo.

For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov. For additional images visit the Cassini imaging team homepage http://ciclops.org.