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Dawn’s coverage of Ceres, December 16 to March 11

Dawn’s coverage of Ceres, December 16 to March 11
Dawn’s coverage of Ceres, December 16 to March 11 This is an accelerated excerpt from this complete animation showing Dawn’s accumulated photographic coverage of Ceres during the lowest altitude mapping campaign from December 16 to March 11. To ensure that it can see all latitudes, Dawn travels in a polar orbit, flying from the north pole to the south pole over the illuminated hemisphere and back to the north over the nighttime hemisphere. Each orbital revolution takes 5.4 hours. Meanwhile, Ceres rotates from east to west, completing one Cerean day in just over nine hours. The combined motion causes the spacecraft’s path over the landscape to follow these graceful curves. Consecutive orbits pass over widely separated regions because Ceres continues to rotate beneath Dawn while the spaceship glides over the hidden terrain of the night side. The swaths that don’t fit the typical pattern are the extra pictures Dawn took as it turned away from the scenery below it, as described in January. The spacecraft does not take pictures on every orbit, because sometimes it performs other functions (such as pointing its main antenna to Earth), so that causes gaps that are filled in later. Note that the center of the popular Occator Crater (slightly above and to the right of center), just happened to be one of the last places to be imaged as Dawn progressively built its high-resolution map. NASA / JPL-Caltech / UCLA / MPS / DLR / IDA