Verification of a system to prevent aircraft illumination by adaptive optics laser beacons

Laser beams directed into the sky from astronomical observatories to genera te guide beacons for adaptive optics image-sharpening systems are a potenti al hazard to aircraft. Detection systems are needed to sense aircraft and i nterrupt the laser beam to prevent accidental illumination. We describe her e a system designed for this task. A computer examines CCD images of the sk y over a wide held of view and uses a motion detection algorithm to find tr acks made by aircraft lights. The results of tests, conducted with simultan eous radar coverage from Tucson International Airport, are reported. A test with an actual laser beacon at the Multiple Mirror Telescope in which Mars was used as a simulated aircraft is also described.