The left-hand image is a Dawn FC (framing camera) image, which shows the apparent brightness of Vesta's surface. The right-hand image is based on this apparent brightness image, which has had a color-coded height representation of the topography overlain onto it. The topography is calculated from a set of images that were observed from different viewing directions, which allows stereo reconstruction. The various colors correspond to the height of the area. The white and red areas in the topography image are the highest areas and the blue areas are the lowest areas. Sossia crater is a middle-sized crater that is offset to the bottom right of the center of the image. Sossia is particularly apparent in the apparent brightness image because is has considerable dark and bright material associated with it. The bright material is mostly in the interior of the crater and the dark material is both inside of and outside of the crater rim. Just outside the bottom rim a smaller crater has excavated a distinctive patch of dark material. A ribbon of dark material appears to extend from the top rim of Sossia towards a similarly sized crater, which is offset from to the top left of the center of the image. It is often difficult to tell whether this dark ribbon is formed of dark material or whether it is a shadow cast by linear ridges or similar structures. A photometrically corrected image, where the shadows have been removed, is necessary to tell apart the dark material and the shadows in this case.
These images are located in Vesta's Urbinia quadrangle, in Vesta's southern hemisphere. NASA's Dawn spacecraft obtained the apparent brightness image with its framing camera on Oct. 25, 2011. This image was taken through the camera's clear filter. The distance to the surface of Vesta is 700 kilometers (435 miles) and the image has a resolution of about 70 meters (230 feet) per pixel. This image was acquired during the HAMO (high-altitude mapping orbit) phase of the mission. These images are lambert-azimuthal map projected.
The Dawn mission to Vesta and Ceres is managed by NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, for NASA's Science Mission Directorate, Washington D.C. UCLA is responsible for overall Dawn mission science. The Dawn framing cameras have been developed and built under the leadership of the Max Planck Institute for Solar System Research, Katlenburg-Lindau, Germany, with significant contributions by DLR German Aerospace Center, Institute of Planetary Research, Berlin, and in coordination with the Institute of Computer and Communication Network Engineering, Braunschweig. The framing camera project is funded by the Max Planck Society, DLR, and NASA/JPL.
More information about Dawn is online at http://www.nasa.gov/dawn and http://dawn.jpl.nasa.gov.