Pefformance of the W.M.Keck Observatory Natural Guide Star Adaptive Optic Facility: the first year at the telescope

摘要

First light for the Keck II Natural Star (NGS) Adaptive Optics (AO) facility was on the night of February 4,1999, On the first attempt at closing the AO loops the image full-width-at-half-maximum (FWHM) went from 0.6 to 0.04 arcesec at H-band (1.65 um wavelength), with a Strehl ratio of 25