Optical sight

A telescopic sight, commonly called a scope, is a sighting device that is based on an optical refracting telescope. They are equipped with some form of graphic image pattern (a reticle) mounted in an optically appropriate position in their optical system to give an accurate aiming point. Telescopic sights are used with all types of systems that require accurate aiming but are most commonly found on firearms, particularly rifles. Other types of sights are iron sights, reflector (reflex) sights, and laser sights. The optical components may be combined with optoelectronics to form a night scope.

The first experiments directed to give shooters optical aiming aids go back to the early 17th century. For centuries different optical aiming aids and primitive predecessors of telescopic sights were created that had practical or performance limitations.

The first documented telescopic rifle sight was invented between 1835 and 1840. In a book titled The Improved American Rifle, written in 1844, civil engineer John R. Chapman documented the first telescopic sights made by Morgan James of Utica, NY. Chapman gave James the concepts and some of the design, whereupon they produced the Chapman-James sight. In 1855, William Malcolm of Syracuse, NY began producing his own sight. Malcolm used an original design incorporating achromatic lenses like those used in telescopes, and improved the windage and elevation adjustments. They were between three and twenty magnification (possibly more). Malcolm's and those made by L. M. Amidon of Vermont were the standard during the Civil War.

Still other telescopic rifle sights of the same period were the Davidson and the Parker Hale.

An early practical refractor telescope based telescopic sight was built in 1880 by August Fiedler (Stronsdorf, Austria), forestry commissioner of Prince Reuss. Later telescopic sights with extra long eye relief became available for handgun and scout rifle use. A historic example of a telescopic sight with a long eye relief is the German ZF41 which was used during World War II on Karabiner 98k rifles.

...
Wikipedia