16 July 2004

The rings of Saturn up close

Amateur and professional astronomers have made countless discoveries over the past several hundred years. Yet the view through telescopes based on Earth can never match what a spacecraft can see from up close.

Consider the remarkable false-color ultraviolet image of portions of Saturn's C and B rings at right. This image was acquired by the Cassini spacecraft's Ultraviolet Imaging Spectrograph instrument when Cassini was being inserted into its orbit around Saturn on 30 June 2004.

The color differences in the rings show distinct changes in their composition. According to the NASA media release, the red-colored rings are composed of "dirty" ice particles while the blue-colored rings are composed of clean ice particles.

Cassini's Ultraviolet Imaging Spectrograph shows features up to 97 kilometers (60 miles) across. This is about 100 times the resolution of ultraviolet data obtained by the Voyager 2 spacecraft, which was launched in 1977 and is now sending back data about the solar wind from deep space.

The image shown here is available at higher resolution at www.nasa.gov/mission_pages/cassini/multimedia/pia05076.html

The Cassini-Huygens mission web site is http://saturn.jpl.nasa.gov . For more information about the visual and infrared mapping spectrometer visit http://lasp.colorado.edu/cassini .

Forrest M. Mims III