Moon Reflects Laser Beams", Pittsburgh Post-Gazette, August 2, 1969, p2 Astronomers at the Lick Observatory in San Jose, California, had been trying for 12 days to strike the 18 inches diameter unit, deployed as part of the mission in order to make precise measurements of the distance between the Earth and the Moon, before finally striking it with the laser and receiving the reflected beam at 2:00 in the morning local time.