Prometheus has just passed -- and gravitationally disturbed -- some of the fine particulate material in the F ring, creating the sheared gap visible in the inner strands of the ring. Prometheus is 102 kilometers (63 miles) across.
This view looks down from about 10 degrees above the ringplane. Prometheus and the rings are sunlit from below. At the lower right lies the outermost part of the A ring, which grows suddenly brighter outside of the 42-kilometer-wide (26-mile) Keeler Gap.
The image was taken in visible green light with the Cassini spacecraft narrow-angle camera on Aug. 2, 2005, at a distance of approximately 632,000 kilometers (392,000 miles) from Prometheus and at a Sun-Prometheus-spacecraft, or phase, angle of 122 degrees. Image scale is 4 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 was designed, developed and assembled at JPL.