Strehl ratio and modulation transfer function for segmented mirror telescopes as functions of segment phase error.
We derive the Strehl ratio for a segmented mirror telescope as a function of the rms segment phase error and the observing wavelength, with and without the effects of the atmosphere. A simple analytical expression is given for the atmosphere-free case. Although our specific results are in the context of the Keck telescope, they are presented in a way that should be readily adaptable to other segmented geometries. We also derive the corresponding modulation transfer functions. These results are useful in determining how accurately a segmented mirror telescope needs to be phased for a variety of observing applications.
Chanan
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Department of Physics and Astronomy, University of California, Irvine, Irvine, California 92697, USA. gchanan@galaxy.ps.uci.edu
Troy
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