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P. Zimmer, J. T. McGraw (Univ. of New Mexico), M. R. Ackermann (Sandia National Laboratory)
We are investigating methods of characterizing turbulence induced index of refraction fluctuations in the surface layer of the atmosphere. At most observatory sites, turbulence in the lowest 100m is the dominant contributor to the seeing disk. It also occurs in a layer of the atmosphere about which we can do something. Better understanding of surface layer effects enables astronomers to make informed decisions about many aspects of observatory operation including siting of new telescopes, improvements to existing telescopes and instrumentation, design of enclosures, and scheduling of observations. We present a technique for measuring full aperture phase fluctuations of an artificial source induced by the surface layer using simultaneous high speed imaging of the pupil and image planes. From these measurements, we can obtain the coherence length, characterized by Fried's parameter r0, and also the shape of the spatial power spectrum of refractive index fluctuations on scales up to the size of the aperture.
The author(s) of this abstract have provided an email address for comments about the abstract: zimm@as.unm.edu
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Bulletin of the American Astronomical Society, 35#5
© 2003. The American Astronomical Soceity.