A sight is an aiming device used to assist in visually 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 device 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, ultravio ...

s that allow the user to see an optically enhanced — often magnified — target image aligned in the same

focus Focus, or its plural form foci may refer to: Arts * Focus or Focus Festival, former name of the Adelaide Fringe arts festival in South Australia Film *''Focus'', a 1962 TV film starring James Whitmore * ''Focus'' (2001 film), a 2001 film based ...

with an

aiming point {{Unreferenced, date=April 2007 In field artillery, the accuracy of indirect fire depends on the use of aiming points. In air force terminology the aiming point (or A.P.) refers to holding the intersection of the cross hairs on a bombsight when fixe ...

(e.g.

telescopic sight A telescopic sight, commonly called a scope informally, is an optical sighting device based on a refracting telescope. It is equipped with some form of a referencing pattern – known as a '' reticle'' – mounted in a focally appropriate ...

reflector sight A reflector sight or reflex sight is an optical sight that allows the user to look through a partially reflecting glass element and see an illuminated projection of an aiming point or some other image superimposed on the field of view. These sig ...

s and

holographic sight A holographic weapon sight or holographic diffraction sight is a non- magnifying gunsight that allows the user to look through a glass optical window and see a holographic reticle image superimposed at a distance on the field of view. The hologram ...

s). 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 sight A laser sight is a device attached or integral to a firearm to aid target acquisition. Unlike optical and iron sights where the user looks through the device to aim at the target, laser sights project a beam onto the target, providing a visual ...

s 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 around ...

illuminators on some

night vision device A night-vision device (NVD), also known as a night optical/observation device (NOD), night-vision goggle (NVG), is an optoelectronic device that allows visualization of images in low levels of light, improving the user's night vision. The devi ...

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 § Ver ...

windage Windage is a term used in aerodynamics, firearms ballistics, and automobiles. Usage Aerodynamics Windage is a force created on an object by friction when there is relative movement between air and the object. Windage loss is the reduction in ...

, 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, ultrav ...

that give the user an enhanced image with an aligned aiming point or pattern (also called a

reticle A reticle, or reticule also known as a graticule, is a pattern of fine lines or markings built into the eyepiece of an optical device such as a telescopic sight, spotting scope, theodolite, optical microscope or the screen of an oscilloscop ...

)

superimpose Superimposition is the placement of one thing over another, typically so that both are still evident. Graphics In graphics, superimposition is the placement of an image or video on top of an already-existing image or video, usually to add to ...

d onto the target image, preferably at the same focal plane.

Telescopic sights

is a

refracting telescope A refracting telescope (also called a refractor) is a type of optical telescope that uses a lens as its objective to form an image (also referred to a dioptric telescope). The refracting telescope design was originally used in spyglasses and a ...

equipped with some form of referencing pattern (

) 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

gun A gun is a ranged weapon designed to use a shooting tube (gun barrel) to launch projectiles. The projectiles are typically solid, but can also be pressurized liquid (e.g. in water guns/cannons, spray guns for painting or pressure washing, p ...

s, surveying equipment, and even as sights on larger telescopes (called a

finderscope A finderscope is an accessory sighting device used in astronomy and stargazing, typically a small auxiliary refracting telescope/ monocular mounted parallelly on a larger astronomical telescope along the same line of sight. The finderscope usu ...

Reflector sights

Mark III free gun reflector sight mk 9 variant reflex sight animation

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 The field of view (FoV) is the extent of the observable world that is seen at any given moment. In the case of optical instruments or sensors it is a solid angle through which a detector is sensitive to electromagnetic radiation. Human ...

. 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 one of the deadliest global conflicts in history. Belligerents included much of Europe, the Russian Empire, the United States, and the Ottoman Empire, with fightin ...

. 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 vast majority of the world's countries—including all of the great powers—forming two opposing ...

Gyro gunsight A gyro gunsight (G.G.S.) is a modification of the non-magnifying reflector sight in which target lead (the amount of aim-off in front of a moving target) and bullet drop are calculated automatically. The first examples were developed in Britain ...

)View from the line
/ref> radar range finding and other flight information in the 1950s and 60s, eventually becoming the modern

head-up display A head-up display, or heads-up display, also known as a HUD (), is any transparent display that presents data without requiring users to look away from their usual viewpoints. The origin of the name stems from a pilot being able to view informa ...

Other types of optical sights

Collimator sight A collimator sight is a type of optical sight that allows the user looking into it to see an illuminated aiming point aligned with the device the sight is attached to, regardless of eye position (with little parallax). They are also referred to as ...

* Holographic weapon sight *

Laser sight A laser sight is a device attached or integral to a firearm to aid target acquisition. Unlike optical and iron sights where the user looks through the device to aim at the target, laser sights project a beam onto the target, providing a visual ...

Red dot magnifier A red dot magnifier is an optical telescope that can be paired with a non-magnifying optical sight on a weapon to create a telescopic sight. They work with the parallel collimated reticle image produced by certain non-magnifying sights so, con ...

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 Computation is any type of arithmetic or non-arithmetic calculation that follows a well-defined model (e.g., an algorithm). Mechanical or electronic devices (or, historically, people) that perform computations are known as ''computers''. An espe ...

, or a mixture of all of these attributes. *

Bombsight A bombsight is a device used by military aircraft to drop bombs accurately. Bombsights, a feature of combat aircraft since World War I, were first found on purpose-designed bomber aircraft and then moved to fighter-bombers and modern tactical ...

Diopter sight The diopter is an aperture sight component used to assist the aiming of devices, mainly firearms, airguns, and crossbows. It is found in particular as a rear sight element on rifles. To obtain a usable sighting line the diopter has to have a com ...

Globe sight A globe sight is a front sight component used to assist the aiming of a gun/device, usually those intended to launch projectiles, such as firearms, airguns, and crossbows. It is found in particular as a front sight element on rifles. To obtain ...

Head-up display A head-up display, or heads-up display, also known as a HUD (), is any transparent display that presents data without requiring users to look away from their usual viewpoints. The origin of the name stems from a pilot being able to view informa ...

* Holographic weapon sight * Iron sight *

Reflector sight A reflector sight or reflex sight is an optical sight that allows the user to look through a partially reflecting glass element and see an illuminated projection of an aiming point or some other image superimposed on the field of view. These sig ...

Red dot sight A red dot sight is a common classification for a type of non- magnifying reflector (or reflex) sight for firearms, and other devices that require aiming, that gives the user a point of aim in the form of an illuminated red dot. A standard desig ...

Telescopic sight A telescopic sight, commonly called a scope informally, is an optical sighting device based on a refracting telescope. It is equipped with some form of a referencing pattern – known as a '' reticle'' – mounted in a focally appropriate ...

Thermal weapon sight A thermographic weapon sight, thermal imagery scope or thermal weapon sight is a sighting device combining a compact thermographic camera and an aiming reticle. They can be mounted on a variety of small arms as well as some heavier weapons. As wi ...

Night vision device A night-vision device (NVD), also known as a night optical/observation device (NOD), night-vision goggle (NVG), is an optoelectronic device that allows visualization of images in low levels of light, improving the user's night vision. The devi ...

* Fire-control system

Notes

External links

{{DEFAULTSORT:Sight (Device) Firearm components Optical devices Artillery components Surveying instruments es:Visor