Rhea displays a marked color contrast from north to south that is
particularly easy to see in the extreme color-enhanced Cassini spacecraft
view presented here.
A clear filter image is also presented (left) alongside the color
composite (right).
To create the false-color view, ultraviolet, green and infrared images
were combined into a single picture that isolates and maps regional color
differences. This "color map" was then superimposed over a clear-filter
image that preserves the relative brightness across the body.
The combination of color map and brightness image shows how colors vary
across the surface of Rhea. The origin of the color differences is not yet
understood, but may be caused by subtle differences in the surface
composition or the sizes of grains making up the icy surface material.
This view looks toward the trailing hemisphere on Rhea (1,528 kilometers,
or 949 miles across). The view shows southerly latitudes on Rhea, down to
the south pole. North is up and rotated 17 degrees to the right.
The image was taken in visible light with the Cassini spacecraft
narrow-angle camera on Jan. 17, 2007 at a distance of approximately
457,000 kilometers (284,000 miles) from Rhea. Image scale is 3 kilometers
(2 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 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/home/index.cfm. The Cassini imaging team
homepage is at http://ciclops.org.
