FIRST ASTRONOMICAL IMAGES SHARPENED WITH ADAPTIVE OPTICS USING A SODIUM LASER GUIDE STAR M Lloyd-Hart J R P Angel T D Groesbeck T Martinez B P Jacobsen B A McLeod 1998

Abstract:  Adaptive optics with a sodium resonance laser guide star was used at the Multiple Mirror Telescope (MMT) in 1996 April to image the core of the globular cluster M13 (NGC 6205). A 23 field was recorded in the K s -band with image resolution of 0.51, when the uncorrected resolution was 0.72. Global tilt, not sensed by the laser, was measured from the image motion of a star 35 from the center of the field. Despite this separation, the star profiles do not vary significantly across the image. Many more stars fainter than K s = 17.5 can be identified in the corrected image. The 0.5 imaging capability here demonstrated, though not reaching the performance of existing faster, higher-order systems with natural star wave-front sensors, is significant because it can be generally realized for very faint objects under normal observing conditions. This characteristic will carry over to higher order laser-based systems, making them very powerful. Our current 0.5 resolution is much larger than the d...