A sight is an aiming device used to assist in
visually
Visual.ly is a community platform for data visualization and infographics.Tsotsis, AlexiaVisual.ly Raises $2 Million To Make Even More Infographics October 20, 2011. It was founded by Stew Langille, Lee Sherman, Tal Siach, and Adam Breckler in ...
aligning
ranged weapons,
surveying instruments or
optical illumination equipments with the intended target. Sights can be a simple set or system of physical markers that have to be aligned together with the target (such as
iron sights on
firearms),
or
optical devices that allow the user to see an optically enhanced — often
magnified
''Magnified'' is the second album by the American alternative rock band Failure.
Production
Drummer Robert Gauss departed during the recording of the album; the remaining drum parts were played by John Dargahi and Greg Edwards.
''Magnified'' dif ...
— target image aligned in the same
focus with an
aiming point (e.g.
telescopic sights,
reflector sights and
holographic sights). There are also sights that actively project an illuminated point of aim (a.k.a. "hot spot") onto the target itself so it can be observed by, such as
laser sights and
infrared
Infrared (IR), sometimes called infrared light, is electromagnetic radiation (EMR) with wavelengths longer than those of visible light. It is therefore invisible to the human eye. IR is generally understood to encompass wavelengths from aroun ...
illuminators on some
night vision devices.
Simple sights
At its simplest, a sight typically has two components, front and rear aiming pieces that have to be lined up. Sights such as this can be found on many types of devices including weapons,
surveying and measuring instruments, and navigational tools.
On weapons, these sights are usually formed by rugged metal parts, giving them the name "
iron sights", as distinct from optical or computing sights. On many types of weapons they are built-in and may be fixed, adjustable, or marked for
elevation
The elevation of a geographic location is its height above or below a fixed reference point, most commonly a reference geoid, a mathematical model of the Earth's sea level as an equipotential gravitational surface (see Geodetic datum § ...
,
windage, target speed, etc.
They are also classified in forms of notch (open sight) or aperture (closed sight). These types of sights can require considerable experience and skill, as the user has to hold proper eye position and simultaneously focus on the rear sight, the front sight, and a target, all at different distances, and align all three ''planes of focus''.
Optical sights

Optical sights use
optics
Optics is the branch of physics that studies the behaviour and properties of light, including its interactions with matter and the construction of instruments that use or detect it. Optics usually describes the behaviour of visible, ultra ...
that give the user an enhanced image with an aligned aiming point or pattern (also called a
reticle)
superimposed onto the target image, preferably at the same
focal plane.
Telescopic sights
A
telescopic sight is a
refracting telescope equipped with some form of
referencing pattern (
reticle) mounted in an optically appropriate position in the optical system to give an accurate aiming point. Telescopic sights are used on a wide range of devices including
guns,
surveying equipment, and even as sights on larger telescopes (called a
finderscope).
Reflector sights

Another type of optical sight is the
reflector (or "''reflex''") sight, a generally non-
magnifying optical device that allows the user to look through a glass element and see a reflection of an illuminated aiming point or some other image superimposed on the
field of view. These sights have been around for over 100 years and have been used on all types of weapons and devices.
Reflector sights were first used as a weapon sight in German aircraft towards the end of
World War I
World War I (28 July 1914 11 November 1918), often abbreviated as WWI, was List of wars and anthropogenic disasters by death toll, one of the deadliest global conflicts in history. Belligerents included much of Europe, the Russian Empire, ...
. Over the years they became more sophisticated, adding lead computing gyroscopes and electronics (the
World War II
World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the World War II by country, vast majority of the world's countries—including all of the great power ...
Gyro gunsight)
View from the line
/ref> radar range finding and other flight information in the 1950s and 60s, eventually becoming the modern head-up display.
Other types of optical sights
* Collimator sight
* Holographic weapon sight
* Laser sight
* Red dot magnifier used in conjunction with a non-magnified optical sight
List of sights
There are many types of sighting devices. They can be fixed, mechanical, optical, computational, or a mixture of all of these attributes.
* Bombsight
* Collimator sight
* Diopter sight
* Globe sight
* Head-up display
* Holographic weapon sight
* Iron sight
* Laser sight
* Reflector sight
** Gyro gunsight
** Red dot sight
* Telescopic sight
* Thermal weapon sight
* Night vision device
* Fire-control system
See also
* Gun laying
* Predicted impact point
* Tritium radioluminescence
Notes
External links
{{DEFAULTSORT:Sight (Device)
Firearm components
Optical devices
Artillery components
Surveying instruments
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