Estimating the point spread function of the adaptive optics system ADONIS using the wavefront sensor measurements

Adaptive Optics (AO) has been developed to compensate the wavefront deforma tion due to the atmospheric turbulence. The wavefront correction, however, is often only partial and a residual blur is present in a long exposure ima ge. It is therefore important to deconvolve the image to do accurate photom etry or to detect faint structures. For this, the point spread function (PS F) has to be known. The PSF is highly variable in time and difficult to cal ibrate. We developed an algorithm which reconstructs the PSF of the ADONIS AO system from the wavefront sensor measurements. We present the results ob tained for different observing conditions and discuss the limits of the met hod. We prove the existence of a local non-stationary turbulence from analy zing the spatial and temporal behaviour of the turbulent phase. We found di fficult to achieve photometric precision higher than 5 to 10% on secondary components of multiple systems with flux ratio larger than 4.