Optical Spotting Instrument

An item used for spotting enemy fire, detecting azimuth and deflection errors in bursts of fire for flash ranging, terrestrial and celestial observation, and for accurate measurement of horizontal and vertical angles by the use of reticles. It may have a single or dual optical syste (s), utilizing a straight or offset (raised) line of sight. It is supported by a tribrach having a leveling plate with adjusting screws, circular and/or tubular level vials, azimuth and elevation controls, and the like. It may be mounted in a tripod or groundshelf mount, and usually includes accommodations for a light, instrument.