Enceladus peeks over the limb of Dione during a partial occultation.
Dione (1,123 kilometers, or 698 miles across), like most of Saturn's icy
moons, has a rather bright, reflective surface. But Enceladus is far and
away brighter. As the most reflective body in the Solar System, Enceladus
returns to space about 99 percent of the visible light that strikes it.
The spray that issues from the geologically active south polar region of
Enceladus (504 kilometers, or 313 miles across) coats the moon in fresh,
white ice and replenishes Saturn's E ring.
Images like this are extremely useful for scientists, as they show both
moons together at approximately the same solar illumination angle. This
gives a reference point for researchers to compare data about how the
moons reflect light when they are not seen together on the sky.
The image was taken in visible light with the Cassini spacecraft
narrow-angle camera on Sept. 13, 2008. The view was acquired at a distance
of approximately 877,000 kilometers (545,000 miles) from Dione and 1.2
million kilometers (740,000 miles) from Enceladus. Image scale is 5
kilometers (3 miles) per pixel on Dione and 7 kilometers (4 miles) per
pixel on Enceladus.
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.
For more information about the Cassini-Huygens mission visit
http://saturn.jpl.nasa.gov/. The Cassini imaging team
homepage is at http://ciclops.org.
