Abstract: A reflecting telescope optical system comprising an elongated rigid base member having front and aft ends, an optical eyepiece fixed to the base member at its aft end, an objective mirror mounted on the front end of the base member and facing the eyepiece, the optical center of said mirror being in alignment with the optical center line of the eyepiece, an optically flat mirror carried by the said base member positioned intermediate the eyepiece and the objective mirror, generally facing the objective mirror but angularly positioned with respect to the plane thereof, and having a central aperture whose axis is in alignment with the said optical center line.

Abstract: A retro-reflective transceiver provides optical communications by reflecting light transmitted by a distant source. The transceiver has a corner cube reflector with a truncated apex that serves as a transmissive aperture. A portion of the incoming light passes through the aperture in the corner cube reflector to a receiver where information encoded on the incoming light beam can be detected. The remainder of the light beam is reflected back toward the source in a direction substantially parallel to the incoming light beam by the three mutually perpendicular, reflective faces of the corner cube reflector. An optical switch (e.g. ferro-electric light crystal material) located in front of the corner cube reflector is used to modulate the intensity of the reflected beam to transmit information to the source.

Abstract: A telescope with a spherical primary mirror and movable lightweight secondary assembly which includes an optical, imaging component and at least one location component both of which components are attached to a pivot arm. The location component can be a microwave, radio frequency or acoustic location component. The optical component of this secondary assembly reflects a portion of focused light radiation from the primary mirror back to the primary mirror and thence through a hole in the secondary mirror to a coude' optics device at the center of curvature of the primary mirror. The coude' optics device in turn reflects the focused light radiation to an imaging detector housed in the outer structure of the telescope. A preferred embodiment of the present invention combines all three of these location systems with the optical imaging component.

Abstract: An optical system having a substantially flat image field is disclosed. The optical system is formed from optical subsystems wherein an input optical subsystem forms an intermediate image has a curvature which compensates that from the remaining optical components of the system to result in a substantially flat image for the optical system. Preferably the optical elements preceding the intermediate image and the optical elements succeeding the intermediate image are separately corrected for odd aberrations. The optical elements preceding the intermediate image and the optical elements succeeding the intermediate image compensate for each other and result in a substantially aberration free flat image for the optical system. The optical system preferably contains an input optical subsystem and an output optical subsystem wherein the input optical subsystem is a catadioptric system and wherein the output optical system is a dioptric system.