A sight or sighting device is any device used to assist in precise

visual The visual system is the physiological basis of visual perception (the ability to detect and process light). The system detects, transduces and interprets information concerning light within the visible range to construct an image and buil ...

alignment (i.e. ''aiming'') of weapons,

surveying Surveying or land surveying is the technique, profession, art, and science of determining the land, terrestrial Plane (mathematics), two-dimensional or Three-dimensional space#In Euclidean geometry, three-dimensional positions of Point (geom ...

instruments, aircraft equipment, optical illumination equipment or larger optical instruments with the intended target. Sights can be a simple set or system of physical markers that serve as visual references for directly aligning the user's

line of sight The line of sight, also known as visual axis or sightline (also sight line), is an imaginary line between a viewer/ observer/ spectator's eye(s) and a subject of interest, or their relative direction. The subject may be any definable object taken ...

with the target (such as

iron sight Iron sights are a system of physical alignment markers used as a sighting device to assist the accurate aiming of ranged weapons such as firearms, airguns, crossbows, and bows, or less commonly as a primitive finder sight for optical telescope ...

s on

firearms A firearm is any type of gun that uses an explosive charge and is designed to be readily carried and operated by an individual. The term is legally defined further in different countries (see legal definitions). The first firearms originated ...

), or

optical instrument An optical instrument is a device that processes light waves (or photons), either to enhance an image for viewing or to analyze and determine their characteristic properties. Common examples include periscopes, microscopes, telescopes, and camera ...

s that provide an optically enhanced—often magnified—target image aligned in the same

focus Focus (: foci or focuses) may refer to: Arts * Focus or Focus Festival, former name of the Adelaide Fringe arts festival in East Australia Film *Focus (2001 film), ''Focus'' (2001 film), a 2001 film based on the Arthur Miller novel *Focus (2015 ...

with an

aiming point 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 fixed at a specific target. An i ...

(e.g.

telescopic A telescope is an instrument designed for the observation of remote objects. Telescope(s) also may refer to: Music * The Telescopes, a British psychedelic band ** The Telescopes (album) * ''Telescope'' (album), by Circle, 2007 * ''The Telescope' ...

, reflector 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 anyone with a direct view, such as

laser sight A laser sight is a device attached or integral to a firearm to aid target acquisition. Unlike Telescopic sight, optical and Iron sights, iron Sight (device), sights where the user looks through the device to aim at the target, laser sights projec ...

s and

infrared Infrared (IR; sometimes called infrared light) is electromagnetic radiation (EMR) with wavelengths longer than that of visible light but shorter than microwaves. The infrared spectral band begins with the waves that are just longer than those ...

illuminators on some

night vision device A night-vision device (NVD), also known as a night optical/observation device (NOD) or 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 ...

s, as well as

augmented Augment or augmentation may refer to: Language *Augment (Indo-European), a syllable added to the beginning of the word in certain Indo-European languages * Augment (Bantu languages), a morpheme that is prefixed to the noun class prefix of nouns ...

or even

virtual reality Virtual reality (VR) is a Simulation, simulated experience that employs 3D near-eye displays and pose tracking to give the user an immersive feel of a virtual world. Applications of virtual reality include entertainment (particularly video gam ...

-enabled

digital camera A digital camera, also called a digicam, is a camera that captures photographs in Digital data storage, digital memory. Most cameras produced today are digital, largely replacing those that capture images on photographic film or film stock. Dig ...

s ("smart scopes") with software

algorithm In mathematics and computer science, an algorithm () is a finite sequence of Rigour#Mathematics, mathematically rigorous instructions, typically used to solve a class of specific Computational problem, problems or to perform a computation. Algo ...

s that produce digitally enhanced target images.

Iron 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,

and measuring instruments, and navigational tools. On weapons, these sights are usually formed by rugged metal parts, giving them the name "

iron sights Iron sights are a system of physical alignment markers used as a sighting device to assist the accurate aiming of ranged weapons such as firearms, airguns, crossbows, and bows, or less commonly as a primitive finder sight for optical telescop ...

", 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 (geography), ''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 equipotenti ...

windage In aerodynamics, firearms ballistics, and automobiles, windage is the effects of some fluid, usually air (e.g., wind) and sometimes liquids, such as oil. Aerodynamics Windage is a force created on an object by friction when there is relative m ...

, 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 optical instruments, instruments that use or Photodetector, detect it. Optics usually describes t ...

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 or crosshair, 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 electronic v ...

)

superimpose Superimposition is the placement of one thing over another, typically so that both are still evident. Superimpositions are often related to the mathematical procedure of superposition. Audio Superimposition (SI) during sound recording and repro ...

d onto the target image, preferably at the same

focal plane In Gaussian optics, the cardinal points consist of three pairs of points located on the optical axis of a rotationally symmetric, focal, optical system. These are the '' focal points'', the principal points, and the nodal points; there are two ...

Telescopic sights

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 p ...

is a

refracting telescope A refracting telescope (also called a refractor) is a type of optical telescope that uses a lens (optics), lens as its objective (optics), objective to form an image (also referred to a dioptrics, dioptric telescope). The refracting telescope d ...

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 device that Propulsion, propels a projectile using pressure or explosive force. The projectiles are typically solid, but can also be pressurized liquid (e.g. in water guns or water cannon, cannons), or gas (e.g. light-gas gun). So ...

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 usua ...

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 angle, angular extent of the observable world that is visual perception, 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 elec ...

. 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 or the First World War (28 July 1914 – 11 November 1918), also known as the Great War, was a World war, global conflict between two coalitions: the Allies of World War I, Allies (or Entente) and the Central Powers. Fighting to ...

. 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 (1 September 1939 – 2 September 1945) was a World war, global conflict between two coalitions: the Allies of World War II, Allies and the Axis powers. World War II by country, Nearly all of the wo ...

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 ...

) radar range finding and other flight information in the 1950s and 1960s, eventually becoming the modern

head-up display A head-up display, or heads-up display, also known as a HUD () or head-up guidance system (HGS), 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 ...

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 a ...

Holographic weapon sight A holographic weapon sight or holographic diffraction sight is a non-magnification, 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. ...

Laser sight A laser sight is a device attached or integral to a firearm to aid target acquisition. Unlike Telescopic sight, optical and Iron sights, iron Sight (device), sights where the user looks through the device to aim at the target, laser sights projec ...

Red dot magnifier A sight 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 red dot sights and holographic weapon ...

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 A computation is any type of arithmetic or non-arithmetic calculation that is well-defined. Common examples of computation are mathematical equation solving and the execution of computer algorithms. Mechanical or electronic devices (or, historic ...

, 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 tactica ...

Diopter sight A diopter sight is an Iron sight#Aperture sights, aperture sight component used to assist the aiming of ranged weapons, mainly firearms, airguns, and crossbows. Diopters function to precisely align the shooter's eye with the front sight and the ...

Globe sight A globe sight is a front Sight (device), 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 rifl ...

Head-up display A head-up display, or heads-up display, also known as a HUD () or head-up guidance system (HGS), 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 ...

Iron sight Iron sights are a system of physical alignment markers used as a sighting device to assist the accurate aiming of ranged weapons such as firearms, airguns, crossbows, and bows, or less commonly as a primitive finder sight for optical telescope ...

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 aiming point or some image (helping to aim the device, to which the sight is attached, on the target) sup ...

Red dot sight A red dot sight is a common classification for a non- magnifying reflector (or reflex) sight that provides an illuminated red dot to the user as a point of aim. A standard design uses a red light-emitting diode (LED) at the focus of collimati ...

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 p ...

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) or 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 ...

Fire-control system A fire-control system (FCS) is a number of components working together, usually a gun data computer, a director and radar, which is designed to assist a ranged weapon system to target, track, and hit a target. It performs the same task as a hum ...

Notes

External links

The story of how all Miramar Tomcat squadrons got the funds to purchase riflescopes to attach to the HUD of their F-14 fighter jets
{{DEFAULTSORT:Sight (Device) Firearm components Optical devices Artillery components Surveying instruments es:Visor