Adaptive Optics Servo-system Performance Estimator: practical implementation

The evaluation of the quality parameters of the adaptive correction and their evolution with time is important while your adaptive optics system is running. It allows to give an observer a precise feeling of what he will get in the integrated image, it allows the operator to keep an eye on the system performance, and it allows the implementation of adaptive filtering techniques to the servo control laws. These reason have driven us to implement such a tool on the ESO Adonis system. To know the image quality parameters the only possibilities are to directly look at the science image or from the wavefront sensor residuals. Our purpose is to report on our attempts to evaluate the long exposure Strehl ratio and FWHM of the corrected PSF, by using the residual slopes given by the Wave Front Sensor (for us a Shark-Hartmann). We have used the following relation to compute the long exposure strehl1: