* Astronomy

A Laser beam was bounced off the moon's surface successfully on May 9, 1962, by Scientists from MIT.

A ruby optical maser radiating pulses of approximately 50 joules energy, 0.5 msec. duration, at 6943 A was used as the source. The transmitting optical system included a Cassegrain telescope of 12-inch diameter. The echoes were received on a Cassegrain telescope of 48-inch diameter, passed through an interference filter of 7A band-width and were detected with a photomultiplier tube of spectral response type S-20 cooled to liquid nitrogen temperature. The field of view of the receiving telescope was 0.2 milliradians.
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