(See description below)
Epimetheus: Up-Close and Colorful
With this false-color view, Cassini presents the closest look
yet at Saturn’s small moon Epimetheus.
The color of Epimetheus in this view appears to vary in a
non-uniform way across the different facets of the moon’s
irregular surface. Usually, color differences among planetary
terrains identify regional variations in the chemical composition
of surface materials. However, surface color variations can also
be caused by wavelength-dependent differences in the way a
particular material reflects light at different lighting angles.
The color variation in this false-color view suggests such
“photometric effects” because the surface appears to
have a more bluish cast in areas where sunlight strikes the
surface at greater angles.
This false color view combines images obtained using filters
sensitive to ultraviolet, polarized green and infrared light. The
images were taken at a Sun-Epimetheus-spacecraft, or phase, angle
of 115 degrees, thus part of the moon is in shadow to the right.
This view shows an area seen only very obliquely by Voyager.
The slightly reddish feature in the upper left is a crater named
Pollux. The large crater just below it is Hilairea, which has
a diameter of about 33 kilometers (21 miles).
At 116 kilometers (72 miles) across, Epimetheus is slightly
smaller than its companion moon, Janus (181 kilometers, 113 miles
across), which orbits at essentially the same distance from
Saturn.
The images for this color composite were obtained with the narrow
angle camera on March 30, 2005, from a distance of approximately
74,600 kilometers (46,350 miles) from Epimetheus. Resolution in
the original images was about 450 meters (1,480 feet) per pixel.
This view has been magnified by a factor of two to aid
visibility.
Click here for another view of Epimetheus.