An Analysis of Fundamental Waffle Mode in Early AEOS Adaptive Optics Images

Adaptive optics (AO) systems have significantly improved astronomical imagingcapabilities over the last decade, and are revolutionizing the kinds of sciencepossible with 4-5m class ground-based telescopes. A thorough understanding ofAO system performance at the telescope can enable new frontiers of science asobservations push AO systems to their performance limits. We look at recentadvances with wave front reconstruction (WFR) on the Advanced Electro-OpticalSystem (AEOS) 3.6 m telescope to show how progress made in improving WFR can bemeasured directly in improved science images. We describe how a "waffle mode"wave front error (which is not sensed by a Fried geometry Shack-Hartmann wavefront sensor) affects the AO point-spread function (PSF). We model details ofAEOS AO to simulate a PSF which matches the actual AO PSF in the I-band, andshow that while the older observed AEOS PSF contained several times more waffleerror than expected, improved WFR techniques noticeably improve AEOS AOperformance. We estimate the impact of these improved WFRs on H-band imaging atAEOS, chosen based on the optimization of the Lyot Project near-infraredcoronagraph at this bandpass.Comment: 15 pages, 11 figures, 1 table; to appear in PASP, August 200