Influence of scintillations on the performance of adaptive astronomical systems with Hartmann-like wavefront sensors

Instituto de Astronomia, UNAM AP 70-264 Cd. Universitaria, 04510 Mexico D.F., Mexico

Corresponding author: V. V. Voitsekhovich, voisteko@astroscu.unam.mx

Received: 10 November 2000
Accepted: 8 January 2001

Abstract

The influence of scintillations on image centroid measurements and on the phase reconstruction from Hartmann-like wavefront sensors is investigated quantitatively by means of computer simulations. It is shown that under the conditions of astronomical observations, the magnitude of the effect is between 10% (for excellent seeing) and 18% (for poor seeing). However, because the magnitude of the effect increases with the increasing of the turbulence strength, one can expect that under the strong-turbulence conditions the influence of scintillations on the image centroid can be quite strong. So, starting from agiven turbulence strength, it can be impossible to make a successful phase reconstruction from image centroid measurements. It is also shown that the scintillations affect in a different and complicated way the reconstruction quality of different aberrations. Nevertheless one can notice some general tendencies: The scintillations affect more strongly the reconstruction quality of the tip-tilt and high-order aberrations than the reconstruction quality of intermediate aberrations.