Schiaparelli Hemisphere - Orthographic Projection ------------------------------------------------- The image files contained in the SPECIAL/378SO sub-directory are global mosaics of the Schiaparelli Hemisphere of Mars. The original images were acquired during orbit 1,378 of Viking 1 on April 6, 1980. At that time, it was mid northern summer on Mars (aerocentric solar longitude = 89 degrees). The center of this image is near the impact crater Schiaparelli (latitude 0 degrees, longitude 337 degrees). The limits of this mosaic are approximately latitude -60 degrees to 60 degrees and longitude 280 degrees to 30 degrees. The images are in an orthographic projection with scales of 1/4 Degree/Pixel (14.8 KM/Pixel, MC* files), 1/8 Degree/Pixel (7.40 KM/Pixel, MD* files), 1/16 Degree/Pixel (3.70 KM/Pixel, ME* files), 1/32 Degree/Pixel (1.85 KM/Pixel, MF* files), and 1/64 Degree/Pixel (.925 KM/Pixel, MG* files). The MG* files contain selected sub-areas of the mosaic. The color variations have been enhanced in the GIF formatted image files. The large-scale brightness variations (mostly due to sun-angle variations) have been normalized by large-scale filtering. The large circular area with a bright yellow color (in this rendition) is known as Arabia located center right. The boundary between the ancient, heavily- cratered southern highlands and the younger northern plains occurs far to the north (latitude 40 degrees) on this side of the planet, just north of Arabia. The dark streaks with bright margins emanating from craters in the Oxia Palus region (to the left of Arabia) are caused by erosion and/or deposition by the wind. The dark blue area on the far right, called Syrtis Major Planum, is a low-relief volcanic shield of probable basaltic composition. Bright white areas to the south, including the Hellas impact basin at lower right, are covered by carbon dioxide frost. Image Processing by Jody Swann/Tammy Becker/Alfred McEwen, using the PICS (Planetary Image Cartography System) image processing system developed at the U.S. Geological Survey in Flagstaff, Arizona.