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Cassini completes fourth Titan flyby.
NASA's Cassini spacecraft made another close pass of Titan, Saturn's largest moon, on March 31, delivering new images and data from this mysterious moon. Although Titan's northern hemisphere had been imaged by Cassini's radar instrument on a previous flyby, this time it was able to take optical and Infrared pictures that pierced through the moon's thick methane atmosphere. This composite image of four photographs was taken when Cassini was approximately 130,000 km (81,000 miles) away from Titan.
Although the Huygens probe has now pierced the murky skies of Titan and landed on its surface, much of the Moon remains for the Cassini spacecraft to explore. Titan continues to present exciting puzzles.
This view of Titan uncovers new territory not previously seen at this resolution by Cassini's cameras. The view is a composite of four nearly identical wide-angle camera images, all taken using a filter sensitive to wavelengths of Infrared light centered at 939 nanometers. The individual images have been combined and contrast-enhanced in such a way as to sharpen surface features and enhance overall brightness variations.
Some of the territory in this view was covered by observations made by the Cassini synthetic aperture radar in October 2004 and February 2005. At large scales, there are similarities between the views taken by the imaging science subsystem cameras and the radar results, but there also are differences.
For example, the center of the floor of the approximately 80-kilometer-wide (50-mile) crater identified by the radar team in February (near the center in this image, see PIA07368 for the radar image) is relatively bright at 2.2 centimeters, the wavelength of the radar experiment, but dark in the near-infrared wavelengths used here by Cassini's optical cameras. This brightness difference is also apparent for some of the surrounding material and could indicate differences in surface composition or roughness.
Such comparisons, as well as information from observations acquired by the visual and Infrared mapping spectrometer at the same time as the optical camera observations, are important in trying to understand the nature of Titan's surface materials.
The images for this composite view were taken with the Cassini spacecraft on March 31, 2005, at distances ranging from approximately 146,000 to 130,000 kilometers (91,000 to 81,000 miles) from Titan and at a Sun-Titan-spacecraft, or phase, angle of about 57 degrees. The image scale is 8 kilometers (5 miles) per pixel. Previous observations indicate that, due to Titan's thick, hazy atmosphere, the sizes of surface features that can be resolved are a few times larger than the actual pixel scale.
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 team is based at the Space Science Institute, Boulder, Colo.
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