Holographic Measurement and Improvement of the Green Bank Telescope Surface

  title={Holographic Measurement and Improvement of the Green Bank Telescope Surface},
  author={Todd R. Hunter and Frederic R. Schwab and Steven White and John M. Ford and Frank D. Ghigo and Ronald J. Maddalena and Brian S. Mason and John D. Nelson and Richard M. Prestage and Jason Ray and Paul A. Ries and R. Simon and Sivasankaran Srikanth and Peter G. Whiteis},
  journal={Publications of the Astronomical Society of the Pacific},
We describe the successful design, implementation, and operation of a 12 GHz holography system installed on the Robert C. Byrd Green Bank Telescope (GBT). We have used a geostationary satellite beacon to construct high-resolution holographic images of the telescope mirror surface irregularities. These images have allowed us to infer and apply improved position offsets for the 2209 actuators which control the active surface of the primary mirror, thereby achieving a dramatic reduction in the… 

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