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Using five independent analytic and Monte Carlo simulation codes, we have studied the performance of wide field ground layer adaptive optics (GLAO), which can use a single, relatively low order deformable mirror to correct the wavefront errors from the lowest altitude turbulence. GLAO concentrates more light from a point source in a smaller area on the science detector, but unlike traditional adaptive optics, images do not become diffraction-limited. Rather the GLAO point spread function (PSF) has the same functional form as a seeing-limited PSF, and can be characterized by familiar performance metrics such as Full-Width Half-Max (FWHM). The FWHM of a GLAO PSF is reduced by 0.1 ′′ or more for optical and near-infrared wavelengths over different atmospheric conditions. For the Cerro Pachón atmospheric model this correction is even greater when the image quality is worst, which effectively eliminates "bad-seeing" nights; the best seeing-limited image quality, available only 20% of the time, can be achieved 60 to 80% of the time with GLAO. This concentration of energy in the PSF will reduce required exposure times and improve the efficiency of an observatory up to 30 to 40%. These performance gains are relatively insensitive to a number of trades including the exact field of view of a wide field GLAO system, the conjugate altitude and actuator density of the deformable mirror, and the number and configuration of the guide stars.

ABSTRACT. An adaptive optics system is being built for the 6.5 m Multiple Mirror Telescope (MMT) conversion on Mount Hopkins for di †raction-limited observations in the near-infrared. At the heart of the system is a deformable secondary mirror which introduces corrections to the optical wavefront. By compensating these errors at the telescopeÏs secondary, the system has been optimized for low thermal emissivity and high photon throughput. The scientiÐc productivity of the facility will thereby be enhanced in comparison with a telescope equipped with more conventional adaptive optics. The Large Binocular Telescope under construction on Mount Graham will also use adaptive secondary mirrors. This paper explores the beneÐt to both facilities in terms of the integration time required to achieve a given signal-to-noise ratio. The gain is found to be substantial in the photometric bands K, L , M, and N.

We report a multiframe blind deconvolution algorithm that we have developed for imaging through the atmosphere. The algorithm has been parallelized to a significant degree for execution on high-performance computers, with an emphasis on distributed-memory systems so that it can be hosted on commodity clusters. As a result, image restorations can be obtained in seconds to minutes. We have compared and quantified the quality of its image restorations relative to the associated Cramér-Rao lower bounds (when they can be calculated). We describe the algorithm and its parallelization in detail, demonstrate the scalability of its parallelization across distributed-memory computer nodes, discuss the results of comparing sample variances of its output to the associated Cramér-Rao lower bounds, and present image restorations obtained by using data collected with ground-based telescopes.