Contents

11 December 1987
Vol 238, Issue 4833

About The Cover

The 10-meter optical reflector at the Smithsonian Institution's Whipple Observatory in the Santa Rita mountains in southern Arizona. Built in 1968, it is still the largest instrument designed exclusively for use in very high energy gammaray astronomy. See page 1528. [Gary Ladd, Whipple Observatory, Amado, AZ 85645]