ASTRONOMICAL ADAPTIVE OPTICS .2. EXPERIMENTAL RESULTS OF AN OPTIMIZEDMODAL CONTROL

A previous paper discussed the possible improvement of the image quali ty given by an adaptive optics (AO) system by optimizing its spatial a nd temporal correction performance. Considering the perturbed wavefron t as a weighted sum of spatial modes, this optimization leads us to at tribute a specific correction bandwidth to each mode, depending on its signal to noise ratio and correlation time. These parameters are rela ted to the particular observation being carried out as they depend on the magnitude, colour and extension of the reference source, on the se eing conditions and on the system characteristics. In this article the se considerations are verified on the basis of experimental data provi ded by the wave-front analyser of the AO system ComeOnPlus. Algorithms to process the wavefront data are described and their performance and robustness are discussed. The results are analysed and the efficiency of the AO system is derived in terms of the reference source magnitud e and atmospheric conditions.