Saturn's moon Epimetheus moves in front of the larger moon Janus as seen by the Cassini spacecraft.
This view looks toward the leading hemispheres of Epimetheus (113 kilometers, or 70 miles across) and Janus (179 kilometers, or 111 miles across). The moons are lit by sunlight on the left and light reflected off Saturn on the right.
The image was taken in visible green light with the Cassini spacecraft narrow-angle camera on April 2, 2010. The view was obtained at a distance of approximately 2.1 million kilometers (1.3 million miles) from Epimetheus and at a Sun-Epimetheus-spacecraft, or phase, angle of 120 degrees. The view was obtained at a distance of approximately 2.2 million kilometers (1.4 million miles) from Janus and at a Sun-Janus-spacecraft, or phase, angle of 120 degrees as well. Scale in the original image was about 13 kilometers (8 miles) per pixel on both moons. The image has been magnified by a factor of two and contrast-enhanced to aid visibility.
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