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35-642: Similar devices include the Advanced Combat Optical Gunsight (ACOG), manufactured by Trijicon, and the Elcan Specter . SUSAT was the primary sighting system for the British Army 's SA80 series weapons . It was also used with L108 and L110 light machine guns , and mounted to L7 and L111 machine guns. It was phased out and replaced by ACOG and ELCAN sight units during mid-life upgrade programmes. As of March 2019 it

70-543: A digital image superimposed on a screen or eyepiece. Both terms may be used to describe any set of patterns used for aiding visual measurements and calibrations , but in modern use reticle is most commonly used for weapon sights , while graticule is more widely used for non-weapon measuring instruments such as oscilloscope display , astronomic telescopes , microscopes and slides , surveying instruments and other similar devices. There are many variations of reticle pattern; this article concerns itself mainly with

105-586: A dry battery . The first ACOG model, known as the TA01, was released in 1987. The first ACOG model, known as the TA01, was released in 1987. In 1995, United States Special Operations Command selected the 4×32 TA01 as the official scope for the M4 carbine and purchased 12,000 units from Trijicon. Between 2004 and 2005, the TA31RCO-A4 & M4 (AN/PVQ-31A & 31B) was selected as the official Rifle Combat Optic of

140-401: A holographic image of a reticle at finite set range built into the viewing window and a collimated laser diode to illuminate it. An advantage to holographic sights is that they eliminate a type of parallax problem found in some optical collimator based sights (such as the red dot sight ) where the spherical mirror used induces spherical aberration that can cause the reticle to skew off

175-428: A complex background, but lack the precision of thin bars. The most popular types of cross-hair in modern scopes are variants on the duplex cross-hair, with bars that are thick on the perimeter and thin out in the middle. The thick bars allow the eye to quickly locate the center of the reticle, and the thin lines in the center allow for precision aiming. The thin bars in a duplex reticle may also be designed to be used as

210-574: A measure. Called a 30/30 reticle, the thin bars on such a reticle span 30 minutes of arc (0.5º), which is approximately equal to 30 inches at 100 yards or 90 centimeters at 100 meters. This enables an experienced shooter to deduce, on the basis of the known size of an object in view, (as opposed to guess or estimate) the range within an acceptable error limit. Originally crosshairs were constructed out of hair or spiderweb, these materials being sufficiently thin and strong. Many modern scopes use wire crosshairs, which can be flattened to various degrees to change

245-490: A precision pointer . The reticle is said to have been invented by Robert Hooke , and dates to the 17th century. Another candidate as inventor is the amateur astronomer William Gascoigne , who predated Hooke. The term reticle comes from the Latin reticulum , meaning small net. Telescopic sights for firearms, generally just called scopes , are probably the device most often associated with crosshairs. Motion pictures and

280-413: A reticle that indicates the position of Polaris relative to the north celestial pole. Telescopes that are used for very precise measurements would have a filar micrometer as a reticle; this could be adjusted by the operator to measure angular distances between stars. For aiming telescopes, reflex sights are popular, often in conjunction with a small telescope with a crosshair reticle. They make aiming

315-409: A shadow - causing the reticle to be much brighter or darker than the target. Reticles have other features such as a bullet drop compensator and other different reticle shapes such as chevrons . Some ACOG models incorporate rudimentary ghost ring iron sights as a backup for targets that are within 50 m (55 yd). Most ACOG models, when mounted to a carry handle, have an open space through

350-455: A usable life of 10–15 years. Some versions of the ACOG have an additional daytime reticle illumination via a passive external fiber optic light pipe . Normally this allows the brightness of the reticle to match the field of view since it collects ambient light from around the sight, although this can lead to a mismatch in lighting - such as sunlight hitting the light pipe directly, or standing in

385-409: Is near zero if the glass is multicoated (coating being the norm for all modern high quality optical products). Reticles may be illuminated, either by a plastic or fiber optic light pipe collecting ambient light or, in low light conditions, by a battery powered LED . Some sights also use the radioactive decay of tritium for illumination that can work for 11 years without using a battery, used in

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420-742: Is still in use with much of the UK armed forces – primarily reserve, rear-echelon and for training use due to budgetary constraints. It is (or has been) also used by the armies of Cameroon , Oman , Spain and Sweden , in assault rifles such as the Swedish Ak5B and the Spanish CETME LV , although after the replacement of the latter by the HK G36 , those sights have been employed in Rheinmetall MG3 machine guns. A similar unit known as

455-476: Is that they are fairly tough and durable, and provide no obstruction to light passing through the scope. The first suggestion for etched glass reticles was made by Philippe de La Hire in 1700. His method was based on engraving the lines on a glass plate with a diamond point. Many modern crosshairs are actually etched onto a thin plate of glass , which allows a far greater latitude in shapes. Etched glass reticles can have floating elements, which do not cross

490-584: The L2A2 SUIT Sight was used on the L1A1 SLR . The reticle of the SUSAT is of unusual design. Unlike the traditional crosshair layouts commonly used, which are in essence a cross intersecting the target, the SUSAT has a single obelisk -shaped post protruding from the bottom edge of the sight. This type of reticle is sometimes referred to as the "German Post". This obscures the target at long range and

525-593: The United States Marine Corps , prompting Trijicon to produce 100,000 units for the US Marines in the following 18 months. The ACOG is available in a variety of configurations from the manufacturer with different reticles , illumination, and other features. Most ACOGs do not use batteries for reticle illumination, being designed to use internal phosphor illumination provided by the radioactive decay of tritium . The tritium illumination has

560-405: The " Bindon Aiming Concept ", an aiming technique developed by Trijicon founder and optical designer Glyn Bindon. The technique is essentially using the illuminated part of the reticle and its focusing rear eyepiece as a collimator sight . As in any other collimator sight, the user does not actually look through the sight but instead keeps the collimated (infinity) image of the illuminated part of

595-509: The ACOG are designed with bright enough daylight-lit fiber optic or battery-powered LED reticles that facilitate this technique. Trijicon has been the subject of some criticism for inscribing references to Bible verses (e.g. JN8:12, referring to John 8:12 , "I am the Light of the World ") alongside the model numbers on their ACOG sights. Starting in late 2009, Trijicon began shipping sights to

630-733: The ACOG is designed for the Picatinny rail of the M16A4 and M4 , it can be mounted on the carrying handles of previous models by using a special adapter. Trijicon later produced ACOG mounts and adapters for weapons besides the M16, including the Beretta AR70/90 series; SIG SG 550 , Heckler & Koch HK416 , Bushmaster ACR , Enfield L85A2 , and FN SCAR weapon systems; and the Steyr AUG . Several ACOG models are designed to be used with

665-770: The British SUSAT sight for the SA80 (L85) assault rifle and in the American ACOG (Advanced Combat Optical Gunsight) . Red is the most common color used, as it is the least destructive to the shooter's night vision , but some products use green or yellow illumination, either as a single colour or changeable via user selection. Another term for reticle is graticule , which is frequently encountered in British and British military technical manuals. It came into common use during World War I . The reticle may be located at

700-643: The U.S. Military and various law enforcement agencies. In older instruments, reticle crosshairs and stadia marks were made using threads taken from the cocoon of the brown recluse spider . This very fine, strong spider silk makes for an excellent crosshair. In surveying, reticles are designed for specific uses. Levels and theodolites would have slightly different reticles. However, both may have features such as stadia marks to allow distance measurements. For astronomical uses, reticles could be simple crosshair designs or more elaborate designs for special purposes. Telescopes used for polar alignment could have

735-451: The U.S. military without Bible verses. 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 oscilloscope , to provide measurement references during visual inspections . Today, engraved lines or embedded fibers may be replaced by

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770-538: The eyepiece, objective lens and prisms are fitted as assemblies. The SUSAT sight was developed in the United Kingdom by Royal Armament Research Development Establishment (RARDE) and is manufactured by United Scientific Instruments and Avimo , now known as Thales Optics. SUSAT L9A1 Advanced Combat Optical Gunsight The Advanced Combat Optical Gunsight ( ACOG ) is a series of prismatic telescopic sights manufactured by Trijicon . The ACOG

805-456: The foreground. The reticle is tritium -illuminated for low-light condition aiming. The radioactive tritium light source has to be replaced every 8–12 years, since it gradually loses its brightness due to radioactive decay . The L2A2 SUIT Sight uses a similar single post to the SUSAT, but protrudes from the top edge of the sight down to the middle of the field. SUSAT is constructed from a one-piece, pressure die-cast , aluminium body, into which

840-483: The front or rear focal plane (First Focal Plane (FFP) or Second Focal Plane (SFP)) of the telescopic sight. On fixed power telescopic sights there is no significant difference, but on variable power telescopic sights the front plane reticle remains at a constant size compared to the target, while rear plane reticles remain a constant size to the user as the target image grows and shrinks. Front focal plane reticles are slightly more durable, but most American users prefer that

875-447: The media often use a view through crosshairs as a dramatic device, which has given crosshairs wide cultural exposure. While the traditional thin crossing lines are the original and still the most familiar cross-hair shape, they are really best suited for precision aiming at high contrast targets, as the thin lines are easily lost in complex backgrounds, such as those encountered while hunting. Thicker bars are much easier to discern against

910-552: The most rudimentary reticle: the crosshair . Crosshairs are typically represented as a pair of perpendicularly intersecting lines in the shape of a cross, "+", though many variations of additional features exist including dots, posts , concentric circles / horseshoes , chevrons , graduated markings , or a combination of above. Most commonly associated with telescopic sights for aiming firearms , crosshairs are also common in optical instruments used for astronomy and surveying , and are also popular in graphical user interfaces as

945-561: The mount to allow the use of the rifle's iron sights without removing the scope. Others include Docter or Trijicon reflex sights mounted on top, such as the TA11SDO (SU-258/PVQ) and the TA648MGO (SU-260P). The ACOG ECOS line features both of these secondary sighting systems on the same scope. Other features include Picatinny rails like the TA648MGO, flip caps, and the ability to be waterproof up to 11 m (36 ft). Although

980-483: The operator needed a wide field of view to track and range a moving target visually (i.e. weapons from the pre laser / radar / computer era). More recently sights using low power consumption durable light emitting diodes as the reticle (called red dot sight s) have become common on small arms with versions like the Aimpoint CompM2 being widely fielded by the U.S. Military. Holographic weapon sights use

1015-475: The reticle in focus with the dominant eye while the other eye views the entire field of view to acquire the target. In this both-eyes-open technique the brain superimposes the aiming reticle on the target. An added part of the technique is to shift focus after acquisition to the dominant eye/telescopic image for more accurate shooting. This overcomes the problem of centering or acquiring fast traversing targets common with all telescopic sights. Only certain models of

1050-412: The reticle remains constant as the image changes size, so nearly all modern American variable power telescopic sights are rear focal plane designs. American and European high end optics manufacturers often leave the customer the choice between a FFP or SFP mounted reticle. Collimated reticles are produced by non-magnifying optical devices such as reflector sights (often called reflex sights ) that give

1085-408: The reticle; circles and dots are common, and some types of glass reticles have complex sections designed for use in range estimation and bullet drop and drift compensation (see external ballistics ). A potential disadvantage of glass reticles is that the surface of the glass reflects some light (about 4% per surface on uncoated glass ) lessening transmission through the scope, although this light loss

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1120-480: The sight's optical axis . The use of a hologram also eliminates the need for image dimming narrow band reflective coatings and allows for reticles of almost any shape or mil size. A downside to the holographic weapon sight can be the weight and shorter battery life. As with red dot sights, holographic weapon sights have also become common on small arms with versions like the Eotech 512.A65 and similar models fielded by

1155-560: The viewer an image of the reticle superimposed over the field of view, and blind collimator sights that are used with both eyes. Collimated reticles are created using refractive or reflective optical collimators to generate a collimated image of an illuminated or reflective reticle. These types of sights are used on surveying/triangulating equipment, to aid celestial telescope aiming, and as sights on firearms . Historically they were used on larger military weapon systems that could supply an electrical source to illuminate them and where

1190-473: The width. These wires are usually silver in color, but appear black when backlit by the image passing through the scope's optics. Wire reticles are by nature fairly simple, as they require lines that pass all the way across the reticle, and the shapes are limited to the variations in thickness allowed by flattening the wire; duplex crosshairs, and crosshairs with dots are possible, and multiple horizontal or vertical lines may be used. The advantage of wire crosshairs

1225-477: Was originally designed to be used on the M16 rifle and M4 carbine , but Trijicon has also developed ACOG accessories for other firearms. Models provide fixed-power magnification levels from 1.25× to 6×. ACOG reticles are illuminated at night by an internal tritium phosphor . Some versions have an additional daytime reticle illumination via a passive external fiberoptic light pipe or are LED -illuminated using

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