Experimental results from the second generation adaptive optics system on the Starfire Optical Range 1.5 meter telescope

The Starfire Optical Range 1.5 meter telescope is equipped with a 208 subaperture, 241 actuator adaptive optics system operating at visible wavelengths. The adaptive optics are located in a coudé room. A copper vapor laser beam is injected into the coudé feed with a polarizing beam splitter aperture sharing element and is focused at 10 km or greater range in the atmosphere to generate a Rayleigh laser guide star. The wavefront distortion on the returned light is sensed with a Shack-Hartmann sensor. Full aperture tilt of a nearby natural guide star is sensed by computation of the image centroid using a 14×14 CCD array and corrected by control of a fast two axis tip-tilt mirror. The optics are arranged such that either light from a natural star or light returned from a laser guide star can be used for wavefront distortion measurements.