standard sharpshooter equipments during the American Civil War. Other telescopic sights of the same period were the Davidson and the Parker Hale. An early practical refracting telescope based telescopic sight was built in 1880 by August Fiedler (of Stronsdorf, Austria), forestry commissioner of German Prince Reuss. Later telescopic sights with extra long eye relief became available for use on handguns and scout rifles. A historic example of a long-eye relief (LER) telescopic sight is the German ZF41 which was used during World War II on Karabiner 98k rifles. An early example of a man-portable sight for low visibility/night use is the Zielgerät (aiming device) 1229 (ZG 1229), also known by its code name Vampir ("vampire"). The ZG 1229 Vampir was a Generation 0 active infrared night vision device developed for the Wehrmacht for the StG 44 assault rifle, intended primarily for night use. The issuing of the ZG 1229 Vampir system to the military started in 1944 and it was used on a small scale in combat from February 1945 until the final stages of World War II. Types Telescopic sights are classified in terms of the optical magnification (i.e. "power") and the objective lens diameter. For example, "10×50" would denote a fixed magnification factor of 10×, with a 50 mm objective lens. In general terms, larger objective lens diameters, due to their ability to gather a higher luminous flux, provide a larger exit pupil and hence provide a brighter image at the eyepiece. Most early telescopic sights were fixed-power, and were in essence specially designed viewing telescopes. Telescopic sights with variable magnifications appeared later, and were varied by manually adjusting a zoom mechanism behind the erector lenses. Variable-power sights offer more flexibility when shooting at varying distances, target sizes and light conditions, and offer a relative wide field of view at lower magnification settings. The syntax for variable sights is the following: minimal magnification – maximum magnification × objective lens, for example "3-9×40" means a telescopic sight with variable magnification between 3× and 9×, and a 40 mm objective lens. The ratio between the maximum and minimum magnifications of a variable-power sight is known as its "zoom ratio". Confusingly, some older telescopic sights, mainly of German or other European manufacture, have a different classification where the second part of the designation refers to light-gathering power. In these cases, a 4×81 (4× magnification) sight would be presumed to have a