AS GUIDED missiles and rockets are developed, tested, improved, and retested, the tracking equipment which records their trajectory through space must undergo the same pattern of change and improvement. This equipment is highly specialized and its design requires an intimate knowledge of three fields: optics, electronics, and mechanics. At the Perkin-Elmer Corporation we have brought together a group of engineers skilled in all three of these basic and important fields. As a group they have developed astronomical telescopes, advanced bombsights, periscopes, long focal length telephoto lenses, servo and computor control systems. Working from this background, this group has, in recent years, made significant contributions to the guided missile and rocket programs of the United States and several other NATO countries. We would like to describe for you some of the optical tracking instruments already produced or under development by Perkin-Elmer—both at our home plant in Norwalk, Conn., and at our subsidiary Bodenseewerk plant in Ueberlingen, West Germany.