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

Adaptive optics (AO) systems have significantly improved astronomical imaging capabilities over the last decade and are revolutionizing the kinds of science possible with 4–5 m class ground‐based telescopes. A thorough understanding of AO system performance at the telescope can enable new frontiers of science as observations push AO systems to their performance limits. We look at recent advances with wave‐front reconstruction (WFR) on the Advanced Electro‐Optical System (AEOS) 3.6 m telescope to show how progress made in improving WFR can be measured directly in improved science images. We describe how a “waffle mode” wave‐front error (which is not sensed by a Fried geometry Shack‐Hartmann wave‐front sensor) affects the AO point‐spread function. We model details of AEOS AO to simulate a PSF that matches the actual AO PSF in the I band and show that while the older observed AEOS PSF contained several times more waffle error than expected, improved WFR techniques noticeably improve AEOS AO performance. We estimate the impact of these improved WFRs on H‐band imaging at AEOS, chosen based on the optimization of the Lyot Project near‐infrared coronagraph at this bandpass.