A composite of images of 2000 DP107 obtained at Arecibo Observatory in September-October 2000. The frame is 5.8 km vertically, with distance from the observer increasing downward, and 12.2 Hz horizontally, with Doppler frequency or line-of-sight velocity increasing to the right. Rotation and revolution appear counterclockwise. The illuminated front of a roughly spherical primary is visible, as well as the satellite at different phases of the orbital cycle. In this image the satellite appears much smaller than the primary because its spins more slowly. The actual size ratio is about 8 to 3. Also, the orbit appears elliptical in this image, but it is actually circular in space.
Arecibo Observatory/NASA
2000-09-30
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