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The Great Crossing
This life-like movie sequence captures Saturn’s rings during a ring plane crossing–which Cassini makes twice per orbit–from the spacecraft’s point of view. The movie begins with a view of the sunlit side of the rings. As the spacecraft speeds from south to north, the rings appear to tilt downward and collapse to a thin plane, and then open again to reveal the un-illuminated side of the ring plane, where sunlight filters through only dimly.
The striking contrast between the sunlit and unlit sides of the ring plane can now be fully appreciated, thanks to the sense of continuity in time and space provided by this brief clip.
The movie consists of 34 images taken over the course of 12 hours as Cassini pierced the ring plane. Additional frames were inserted between the original images in order to smooth the motion in the sequence – a scheme called interpolation.
Six moons careen through the field of view during the sequence. The first large one is Enceladus, whose slanted motion from the upper left to center right nicely illustrates the inclination of its orbit with respect to the rings. The second large one, seen in the second half of the movie, is Mimas, going from right to left.
This movie begins with a view looking toward the lit side of the rings from about 9 degrees below the ring plane. It ends when the spacecraft is 8 degrees above the ring plane.
The clear-filter images in this movie sequence were taken with the Cassini spacecraft wide-angle camera on Jan. 17, 2007, at a distance of approximately 900,000 kilometers (500,000 miles) from Saturn. Image scale is 48 kilometers (30 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.
Credit: NASA/JPL/Space Science Institute