Lidar-generated artificial guidestars for atmospheric turbulence compensation.

The idea of using lasers to create artificial guide stars for controlling an adaptive imaging system for ground-based telescopes has been extended by identifying the key engineering parameters that optimize the performance of such a system. An artificial guide star created in the mesospheric sodium layer using a tunable-dye laser has been photographed. A lidar system was installed in an observatory dome at the Mauna Kea Observatory with the laser mounted adjacent to a 0.6-m telescope. The collimated laser beam was projected toward the zenith with its own separate optical system. The laser guide spot was imaged by a 500 × 500 CCD array detector mounted at the Cassegrain focus of the U. Hawaii 2.2-m telescope which was located 117 m southeast of the laser. A photon count contour plot of an 8-min exposure of the laser guide spot is shown, and the image characteristics are discussed.