An eerie green glow is frequently seen in the dark hours here at McMurdo: that of the LIDAR or Light Detection and Ranging instruments emerging from Crary Labs. Built by Roberto Morbidini from Rome, Italy, this is one fantastic machine! More impressive than its looks is the sound it makes; worthy of any sci-fi film. It’s chief purpose is to measure PSC’s (see August 27) and correlate the altitudes of these clouds to the ozone hole above us. Shown here is the machine viewed as it exits the building, and finally bottoms out on clouds many miles above. Faint sparkles of ice crystals can be seen traversing this laser beam. This technology can be land based as at McMurdo, launched under a balloon or directed earthward from space. The shuttle uses LIDAR technology to determine not only it’s altitude, but the quality of the surface it passes over.