<title>Study of anisoplanatism using binary stars</title>

Abstract

ABSTRACT We report on an ongoing experiment at the Starfire Optical Range to study anisoplanatism and investigate a methodof mitigating its effect on adaptive optics systems. We have collected Hartmann sensor wave front measurementson binary stars having a variety of separations and have reconstructed wave fronts based on these measurements.At the same time the wave front data was collected, we measured the C profile using a balloon-borne instrument.Using these data, we plan to study anisoplanatism in terms of the structure function and Zernike polynomials. Wealso plan to investigate whether wave front compensation can be improved by moving the wave front corrector fromthe aperture plane to a plane determined from the refractive index profile. 1 INTRODUCTION Anisoplanatism is the decorrelation of the atmospheric optical transfer function over different propagation paths.In particular, atmospheric phase distortion decorrelates rapidly with respect to the separation angle between pointsources, limiting the ability of adaptive optics systems to achieve good compensation over a wide field of view.Research has suggested that the compensated field of view of an adaptive optical telescope could be increased bymoving the plane of compensation (i.e. the plane where the deformable mirror is located) from the aperture to aplane where the turbulence is chiefly concentrated, or by using multiple wave front correctors conjugated to multipleplanes.