Four of Saturn's many and varied moons crowd this single frame from Cassini.
All of the moons are illuminated by the sun, which is out of the frame to the right. "Saturnshine," or reflected light from the planet (out of frame to the lower left), partly illuminates three of the moons: Tethys (1,071 kilometers, or 665 miles across, at upper right), Janus (181 kilometers, or 113 miles across, at lower left) and Epimetheus (116 kilometers, or 72 miles across, below and left of center). Enceladus (505 kilometers, or 314 miles across) shows merely a slim crescent below center.
The image was taken in visible light with the Cassini spacecraft narrow-angle camera on April 17, 2006, at a distance of approximately 3.7 million kilometers (2.3 million miles) from Saturn. The image scale is 27 kilometers (17 miles) per pixel on Tethys, 21 kilometers (13 miles) per pixel on Enceladus, and 22 kilometers (14 miles) per pixel on Janus and Epimetheus.
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.
Credit:NASA/JPL/Space Science Institute