The largest steerable radio telescope in the United States (Fig. 1) has recently been completed at the U.S. Naval Research Laboratory's Maryland Point Observatory in Charles County, Maryland. The new instrument, an 84-foot parabolic antenna, or “dish,” was designed by the D. S. Kennedy Co. of Cohasset, Massachusetts. Originally ordered in June 1955, the instrument has been three years in design, construction, and erection. Carried on a polar or equatorial mount, the 84-foot aluminum reflector can be aimed at any point in the sky and can track any celestial object from horizon to horizon. It is the largest antenna with this type of mounting in the world.