September 20, 2005
This unique movie, showing Saturn's rotation in three different spectral filters, demonstrates Cassini's ability to probe various levels within the planet's outer cloud layers.
From left to right, the three panes show the atmosphere at infrared wavelengths 752, 728 and 890 nanometers. The filter used at the left is seeing the "deep cloud" layer, which has more features than any other Cassini view. The filter at the right shows the highest altitude cloud layers.
Cassini's powerful cameras reveal atmospheric processes beneath the layer visible to the human eye, but these views show only the thinnest outer skin of the planet, whose radius is about 60,000 kilometers (37,000 miles). The altitude difference between the left and right panels is estimated to be in the range of 30 to 100 kilometers (20 to 60 miles).
Although the left and center panels sample wavelengths that are relatively close together, the different morphology seen in these panels shows that the two filters are sampling different heights.
The movie covers a period of about 95 minutes and consists of 31 images in each of the three panes. One Saturn rotation is about 10.7 hours long (determined by the rotation of the planet's magnetic field).
The movie has been compressed to decrease the overall file size, and as a result, some small artifacts are present. However, all of the large-scale features visible here are real.
Cassini captured the images comprising this movie with its wide angle camera on June 21, 2005, at a distance of approximately 2.2 million kilometers (1.4 million miles). The image scale is about 125 kilometers (78 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