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
Parallax is a displacement or difference in the apparent position of an object viewed along two different sightline, lines of sight and is measured by the angle or half-angle of inclination between those two lines. Due to perspective (graphica ...
). They are also referred to as collimating sights or "occluded eye gunsight" (OEG).
Description
The basic layout of a
collimator
A collimator is a device which narrows a beam of particles or waves. To narrow can mean either to cause the directions of motion to become more aligned in a specific direction (i.e., make collimated light or parallel rays), or to cause the spat ...
sight is a closed tube with a lens at its open end and a luminous
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 ...
mounted near the closed end at the focus of the lens, creating an
optical collimator. The reticle is illuminated by an electronic light source (an
incandescent light bulb
An incandescent light bulb, also known as an incandescent lamp or incandescent light globe, is an electric light that produces illumination by Joule heating a #Filament, filament until it incandescence, glows. The filament is enclosed in a ...
or, more recently, a
light-emitting diode
A light-emitting diode (LED) is a semiconductor device that emits light when current flows through it. Electrons in the semiconductor recombine with electron holes, releasing energy in the form of photons. The color of the light (corre ...
) or by ambient light gathered behind the reticle via an
opalescent window or
fiber optic light pipe. Collimator sights are a relatively old idea, being used in many forms for almost 100 years.
Usage
Collimator sights, also known as occluded eye gunsights (OEGs), are designed for use with both eyes open. The user aligns one eye with the sight while the other eye remains open and focused on the target. This allows the brain to superimpose the aiming reticle onto the target, creating a composite image. Alternatively, the user can adjust their head position to switch between viewing the sight and the target with the same eye or use a partial alignment to see both the sight and the target simultaneously.
Applications
Collimator sights as weapon sights are considered to be very simple, rugged and low cost devices. They have been used on
mortars and
field gun
A field gun is a field artillery piece. Originally the term referred to smaller guns that could accompany a field army on the march, that when in combat could be moved about the battlefield in response to changing circumstances (field artillery ...
s since
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 ...
. There have had more modern incarnations such as the Armson ''Occluded Eye Gunsight'' (OEG) and the Normark Corp. ''Singlepoint''. These both used a light gathering rod in a protective clear dome collecting ambient light to illuminate a 'dot' style
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 ...
.
Collimator sights have had uses as a small arms sight for low light situations (such as twilight or "room clearing" operations) since there is no intervening optical window that can block the light, allowing the use of both eyes with a relatively un-obstructed field of view.
[Maj. Michael J. Stroff III, USMCR, Night Marksmanship: A Step Forward, Marine Corps Gazette; vol 74 no 4; Apr 1990; pp. 44-45 illus] In recent years the introduction of illuminated
reflex 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 ...
s,
holographic sights, and even
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 ...
s; (for example the
Advanced Combat Optical Gunsight
The Advanced Combat Optical Gunsight (ACOG) is a series of prismatic telescopic sights manufactured by Trijicon. The ACOG was originally designed to be used on the M16 rifle and M4 carbine, but Trijicon has also developed ACOG accessories for ...
(ACOG) using the "
Bindon Aiming Concept") have replaced dedicated collimator sights since these other types of sights can be used with both eyes in the role of a collimator sight.
Collimator sights are also used in astronomy as
Finderscopes to aim a telescope at a designated celestial object.
See also
*
Glossary of military abbreviations
List of abbreviations, acronyms and initials related to military subjects such as modern armor, artillery, infantry, and weapons, along with their definitions.
A
* A&TWF – Acquisition and technology work force
* a – Army
* AA – Assembly a ...
*
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 ...
*
Collimated beam
References
{{Reflist
Firearm sights
Optical devices