A rangefinder is a device used to measure distances to remote objects. Originally optical devices used in surveying, they soon found applications in other fields, such as photography, the military, an
Portable German stereoscopic rangefinder from WWII
The coincidence rangefinder of the Polish destroyer ORP Wicher
Second World War German range finding tower at La Corbière, Jersey
A stereoscopic rangefinder or stereoscopic telemeter is an optical device that measures distance from the observer to a target, using the observer's capability of binocular vision. It looks similar to
Rangefinder
…from the observer, sited on a high vantage point, to the waterline of the target vessel. In 1899, Carl Pulfrich at Carl Zeiss AG fabricated a practical stereoscopic rangefinder, based on a patent of Hector Alexander de Grousilliers. World War II-era rangefinders worked optically with two telescopes focused on the same target…
Stereoscopic rangefinder atop the bridge of the German cruiser Admiral Graf Spee
Stereoscopic rangefinder (Bausch & Lomb M2) at Overloon War Museum, Netherlands.
German stereoscopic rangefinder (Em.4m.R40) at Musee Royale de l'Armee et d'Histoire Militaire, Brussels.