Saturn's moon Prometheus is seen here emerging from the darkness of Saturn's shadow. Prometheus is 102 kilometers (63 miles) across.
This shepherd moon, like most of Saturn's moons, always keeps the same face pointing toward the planet. An observer on the moon's Saturn-facing side would never see the Sun directly overhead at noon, for the planet would always be in the way (creating an eclipse). Instead, the Sun would rise in the east, but as noon approached the eclipse would begin, bringing darkness a second time. Night comes twice on Prometheus.
This image was taken in visible light with the Cassini spacecraft narrow-angle camera on June 3, 2005, at a distance of approximately 2.1 million kilometers (1.3 million miles) from Saturn. The image scale is 13 kilometers (8 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.
Credit: NASA/JPL/Space Science Institute