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J. Christou, E. Steinbring, S. Faber (Center for Adaptive Optics), D. Gavel, J. Patience (Lawrence Livermore National Laboratory), E. Gates (Lick Observatory)
Anisoplanatism, i.e. the spatial variation of the point spread function (PSF), needs to be understood for Adaptive Optics (AO) observations over relatively large fields. Using the Lick Observatory AO system, we have obtained measurements of tip-tilt anisoplanatism and high-order ansioplanatism within the isoplanatic patch, the region typically considered to have PSF stability.
Using binary stars with separations of ~ 7\prime\prime and ~12\prime\prime we have measured PSF variations even though the isoplanatic patch was estimated to be ~26\prime\prime. The differential tip-tilt motion was measurable but small compared to the size of the diffraction spot so that anisoplanatism was dominated by the high-order contribution.
We consider how this PSF variability will affect the analysis of targets within the isoplanatic patch, specifically PSF calibration for quantitative measurements.
This work has been supported by the National Science Foundation Science and Technology Center for Adaptive Optics, managed by the University of California at Santa Cruz under cooperative agreement No. AST - 9876783.
The author(s) of this abstract have provided an email address for comments about the abstract: christou@ucolick.org
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Bulletin of the American Astronomical Society, 34, #4
© 2002. The American Astronomical Soceity.