Saturn's moon Epimetheus moves in front of the larger moon Janus as seen by Cassini.
This view looks toward the leading hemispheres of Epimetheus (113 kilometers, 70 miles across) and Janus (179 kilometers, 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. 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 Equinox Mission is a joint United States and European endeavor. 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. The imaging team consists of scientists from the US, England, France, and Germany. The imaging operations center and team lead (Dr. C. Porco) are based at the Space Science Institute in Boulder, Colo.