title: Performance of the Keck Observatory adaptive-optics system.
abstract: The adaptive-optics (AO) system at the W. M. Keck Observatory is characterized. We calculate the error budget of the Keck AO system operating in natural guide star mode with a near-infrared imaging camera. The measurement noise and bandwidth errors are obtained by modeling the control loops and recording residual centroids. Results of sky performance tests are presented: The AO system is shown to deliver images with average Strehl ratios of as much as 0.37 at 1.58 microm when a bright guide star is used and of 0.19 for a magnitude 12 star. The images are consistent with the predicted wave-front error based on our error budget estimates.
authors.affiliation: Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94550, USA. mvandam@keck.hawaii.edu
authors.forename: Marcos A
authors.initials: MA
authors.lastname: van Dam
authors.forename: David
authors.initials: D
authors.lastname: Le Mignant
authors.forename: Bruce A
authors.initials: BA
authors.lastname: Macintosh