Photometry with adaptive optics: A first guide to expected performance

This paper aims to help prospective observers estimate the likely performance of adaptive optics for photometric observations. Both real and simulated adaptive optics data are used in specific examples covering the major observational situations. These illustrate the different sources of uncertainty: seeing fluctuations, presence of both a large halo and residual fluctuations in the point spread function, and angular anisoplanatism. The astronomical cases studied include isolated sources, faint structures around a star, and crowded stellar fields. The photometric performance image deconvolution is also examined. No attempt is made to investigate exhaustively all possible atmospheric conditions and observing configurations, but the discussion should be a useful guide to the feasibility of using adaptive optics in astronomical programmes requiring particular photometric accuracies.