The rangefinding telemeter (or simply telemeter or rangefinder, depending on the context), is a device used to measure distances to remote objects, that is, a type of rangefinder. The name is derived from the Ancient Greek: τῆλε tēle “far away” and μέτρον métron “something used to measure”. World War II era telemeters worked optically with two telescopes focused on the same target but a distance apart along a baseline. The range to the target is found by measuring the difference in bearing of the two telescopes and solving the skinny triangle. Solutions can be obtained automatically, using tables or, rarely, manual calculation. The greater the distance to the target, the longer the baseline needs to be for accurate measurement. The baseline required for the telemeters for battleship guns is very large. More modern telemeters use an electronic technology such as lasers or radar.

Type: Telemeter
Category: Field Props