A sight is an aiming device used to assist in visually aligning ranged weapons,

surveying Surveying or land surveying is the technique, profession, art, and science of determining the terrestrial two-dimensional or three-dimensional positions of points and the distances and angles between them. A land surveying professional is ...

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 sight Iron sights are a system of physical alignment markers (usually made of metallic material) used as a sighting device to assist the accurate aiming of ranged weapons (such as a firearm, airgun, crossbow or even compound bow), or less commonly ...

s on

firearms A firearm is any type of gun designed to be readily carried and used by an individual. The term is legally defined further in different countries (see Legal definitions). The first firearms originated in 10th-century China, when bamboo tubes ...

), or optical devices that allow the user to see an optically enhanced — often magnified — target image aligned in the same focus 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 ...

s, 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 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 visua ...

s and

infrared Infrared (IR), sometimes called infrared light, is electromagnetic radiation (EMR) with wavelengths longer than those of Light, visible light. It is therefore invisible to the human eye. IR is generally understood to encompass wavelengths from ...

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,

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 (usually made of metallic material) used as a sighting device to assist the accurate aiming of ranged weapons (such as a firearm, airgun, crossbow or even compound bow), or less commonly ...

", 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, ultrav ...

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 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. For ''ideal'' ...

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 an ...

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,

equipment, and even as sights on larger telescopes (called a finderscope).

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. 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 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 visua ...

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, or a mixture of all of these attributes. * Bombsight * Collimator sight * Diopter sight * Globe sight * Head-up display * Holographic weapon sight *

Iron sight Iron sights are a system of physical alignment markers (usually made of metallic material) used as a sighting device to assist the accurate aiming of ranged weapons (such as a firearm, airgun, crossbow or even compound bow), or less commonly ...

* Reflector sight ** Gyro gunsight ** Red dot sight *

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 * Night vision device *

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 ...

Notes

External links

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