Spacecraft near and far are watching Saturn
SPACE TELESCOPE SCIENCE INSTITUTE NEWS RELEASE
Posted: May 26, 2004
As Saturn grows closer through the eyes of the Cassini spacecraft, which is hurtling toward a rendezvous with the ringed world on June 30 (July 1, Universal Time), both Cassini and the Earth-orbiting Hubble Space Telescope snapped spectacular pictures of the planet and its magnificent rings.
The view from Hubble, taken on March 22, 2004, is so sharp that many individual Saturnian ringlets can be seen. When Cassini returned its picture of Saturn on May 16, it was so close to the planet that the Imaging Science Subsystem narrow-angle camera could not fit the whole planet in its field-of-view. Cassini is still about 12.4 million miles (about 20 million kilometers) away and only 36 days from reaching Saturn.
Hubble's exquisite optics, coupled with the high resolution of its Advanced Camera for Surveys, allow it to take pictures of Saturn which are nearly as sharp as Cassini's, even though Hubble is nearly a billion miles farther from Saturn than Cassini. Cassini will ultimately far exceed the resolution of Hubble during its close encounter with Saturn. Cassini's sharpness began to surpass Hubble's when it came to within 14 million miles (23 million kilometers) of Saturn earlier this month.
Cassini has two cameras, a wide angle and narrow angle. This narrow angle image was made using a combination of three filters (red, green, blue) and was taken at a range of 15.1 million miles (24.3 million kilometers). The view is from 13 degrees below the equator. Enceladus, one of Saturn's 31 known moons, appears near the south pole at the bottom of the image.
The differences between the Hubble and Cassini images are mainly due to the different sets of filters used.
Cassini will begin a four-year mission in orbit around Saturn when it arrives on June 30, 2004 PDT (July 1, 2004 UTC). Six months later it will release its piggybacked Huygens probe for descent through Titan's thick atmosphere.
The Space Telescope Science Institute is operated by the Association of Universities for Research in Astronomy, Inc., for NASA, under contract with the Goddard Space Flight Center, Greenbelt, Md. The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. The Cassini-Huygens mission is a cooperative mission 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 Office of Space Science, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL.