Luftwaffe Flak personnel using a Kommandogerät 36 (Kdo. Gr. 36) rangefinder, which is part of a battery of four 8.8 cm anti aircraft guns. Using trigonometry, the 4-meter base stereoscopic range finder has a magnification of 12x and 24x, and a range scale reading from 500 meters (550 yards) to 50,000 meters (55,000 yards). It is clamped by two rings to the mount, and kept in a chest while in transit. The instrument is manufactured by the famous Carl Zeiss optics company in Jena, and displays excellent workmanship.
The Kommandogerät 36 measures target course and speed. Ballistic data are obtained from graphical drums; varying heights are accepted, and corrections can be applied for wind, drift, displacement, dead time, and variations in muzzle velocity. Readings must be called out to the operator on the director. Information is passed from one operator to another by voice and via a telephone system. The target data are used to set the fuses of the grenades and to provide aiming points for the guns.
Period photos of this particular piece of equipment are relatively scarce on the Internet, so I’m happy to own this photograph.