 |
 |
| Annotated Image | Exaggerated Color Contrast |
With giant Saturn hanging in the blackness and sheltering Cassini from the
sun's blinding glare, the spacecraft viewed the rings as never before,
revealing previously unknown faint rings and even glimpsing its home
world.
This marvelous panoramic view was created by combining a total of 165
images taken by the Cassini wide-angle camera over nearly three hours on
Sept. 15, 2006. The full mosaic consists of three rows of nine wide-angle
camera footprints; only a portion of the full mosaic is shown here. Color
in the view was created by digitally compositing ultraviolet, infrared and
clear filter images and was then adjusted to resemble natural color.
The mosaic images were acquired as the spacecraft drifted in the darkness
of Saturn's shadow for about 12 hours, allowing a multitude of unique
observations of the microscopic particles that compose Saturn's faint
rings.
Ring structures containing these tiny particles brighten substantially at
high phase angles: i.e., viewing angles where the sun is almost directly
behind the objects being imaged.
During this period of observation Cassini detected two new faint rings:
one coincident with the shared orbit of the moons Janus and Epimetheus,
and another coincident with Pallene's orbit. (See PIA08322 and
PIA08328 for more on the two new rings.)
The narrowly confined G ring is easily seen here, outside the bright main
rings. Encircling the entire system is the much more extended E ring. The
icy plumes of Enceladus, whose eruptions supply the E ring particles,
betray the moon's position in the E ring's left-side edge.
Interior to the G ring and above the brighter main rings is the pale dot
of Earth. Cassini views its point of origin from over a billion kilometers
(and close to a billion miles) away in the icy depths of the outer solar
system. See PIA08324 for a similar view of Earth taken during this observation.
Small grains are pushed about by sunlight and electromagnetic forces.
Hence, their distribution tells much about the local space environment.
A second version of the mosaic view is presented here in which the
color contrast is greatly exaggerated. In such views, imaging scientists
have noticed color variations across the diffuse rings that imply active
processes sort the particles in the ring according to their sizes.
Looking at the E ring in this color-exaggerated view, the distribution of
color across and along the ring appears to be different between the right
side and the left. Scientists are not sure yet how to explain these
differences, though the difference in phase angle between right and left
may be part of the explanation. The phase angle is about 179 degrees on
Saturn.
The main rings are overexposed in a few places.
This view looks toward the unlit side of the rings from about 15 degrees
above the ringplane.
Cassini was approximately 2.2 million kilometers (1.3 million miles) from
Saturn when the images in this mosaic were taken. Image scale on Saturn is
about 260 kilometers (162 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.
