|Cassini Arrives at Saturn|
are some fascinating images from Cassini. The first is a close up shot of the rings taken nine
days before it entered orbit. This exquisite natural color view of
Saturn's rings was obtained from Cassini's vantage point beneath the
ring plane with the narrow angle camera on June 21, 2004, at a distance
of 6.4 million kilometers (4 million miles) from Saturn. The image scale
is 38 kilometers (23 miles) per pixel.
The brightest part of the rings, curving from the upper right to the lower left in the image, is the B ring. Many bands throughout the B ring have a pronounced sandy color. Other color variations across the rings can be seen. Color variations in Saturn's rings have previously been seen in Voyager and Hubble Space Telescope images. Cassini's images show that color variations in the rings are more pronounced in this viewing geometry than they are when seen from Earth.
Saturn's rings are made primarily of water ice. Since pure water ice is white, it is believed that different colors in the rings reflect different amounts of contamination by other materials such as rock or carbon compounds. In conjunction with information from other Cassini instruments, Cassini images will help scientists determine the composition of different parts of Saturn's ring system.
The other images were sent back from the spacecraft as it passed through the rings during the braking manoeuvre. Note in particular the little moonlets which are visible in several images and which are clearly stabilizing the gaps in the rings. Go HERE for a selection of pictures of the moons.
And what about this mosaic of Saturn which
was compiled from a series of 126 images taken over
the course of two hours on Oct. 6, 2004, while Cassini was approximately
6.3 million kilometers (3.9 million miles) from Saturn. Since the view
seen by Cassini during this time changed very little, no re-projection
or alteration of any of the images was necessary.
Three images (red, green and blue) were taken of each of 42 locations, or "footprints," across the planet. The full colour footprints were put together to produce a mosaic that is 8,888 pixels across and 4,544 pixels tall. This image has of course been re-sized and re-sampled for download speed, but if you have a fast connection and would like to see the original 5.5 Mb Image click here.
The smallest features seen here are 38 kilometers (24 miles) across. Many features noted previously in single frames taken by Cassini are visible in this one detailed, all-encompassing view: subtle colour variations across the rings, the thread-like F ring, ring shadows cast against the blue northern hemisphere, the planetís shadow making its way across the rings to the left, and blue-grey storms in Saturn's southern hemisphere to the right. Tiny Mimas and even smaller Janus are both faintly visible at the lower left.
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