Astronomy: Spots on the Moon

Air Force Observers James C. Greenacre and Edward M. Barr had a painstaking job: with the 24-in. telescope of the Lowell Observatory at Flagstaff, Ariz., they were to map a part of the moon—the well-defined crater Aristarchus, 27 miles in diameter. Both men were thoroughly familiar with the crater and its vicinity; Greenacre could hardly believe his eyes when he saw two bright red spots looming to the northwest and a third just inside the crater's rim. "I had the impression that I was looking into a large, polished gem ruby," he says.

The spots lasted less than 20 minutes...

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