Radar animations

Courtesy Marina B and DSS-13/GBT/JPL/Caltech/NASA

Two sequences of delay-Doppler images from October 12 obtained with DSS-13 (Goldstone's 34 m antenna) transmitting and the Green Bank Telescope (GBT) receiving. The short sequence, 03:14-03:23 UTC was obtained just prior to the 2012 TC4 close approach, while the long sequence, 13:09-19:00 UTC was obtained after the close approach. Time delay (range) increases from top to bottom and Doppler frequency increases from left to right. The range resolution is 1.875 m and Doppler frequency resolution is 0.2 Hz. The vertical dimension of each image is 187.5 m and the horizontal dimension is 20 Hz. Labels contain the start times of 20 s data integration. Assuming ~12 min rotation period, each delay-Doppler image averages ~10 deg of the object's rotation. The echo drifts from top to bottom in the long sequence because of a small Doppler error (<0.1 Hz) in the orbital predicts for 2012 TC4.
Credit: DSS-13/GBT/JPL/Caltech/NASA

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