{{Other uses, Susat (disambiguation){{!Susat SA80 A2 (L85A2) 5

The Sight Unit Small Arms, Trilux, or SUSAT, is a 4×

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 po ...

, with

tritium Tritium ( or , ) or hydrogen-3 (symbol T or H) is a rare and radioactive isotope of hydrogen with half-life about 12 years. The nucleus of tritium (t, sometimes called a ''triton'') contains one proton and two neutrons, whereas the nucleus o ...

-powered illumination utilised at

dusk Dusk occurs at the darkest stage of twilight, or at the very end of astronomical twilight after sunset and just before nightfall.''The Random House College Dictionary'', "dusk". At predusk, during early to intermediate stages of twilight, enou ...

dawn Dawn is the time that marks the beginning of twilight before sunrise. It is recognized by the appearance of indirect sunlight being scattered in Earth's atmosphere, when the centre of the Sun's disc has reached 18° below the observer's horizo ...

. The full name of the current model is the SUSAT L9A1. The sight is not designed as a

sniper A sniper is a military/paramilitary marksman who engages targets from positions of concealment or at distances exceeding the target's detection capabilities. Snipers generally have specialized training and are equipped with high-precision r ...

sight, but is rather intended to be mounted on a variety of rifles and to be used by all infantrymen. A similar device is 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 ot ...

Use

SUSAT was the primary sighting system for the

British Army The British Army is the principal land warfare force of the United Kingdom, a part of the British Armed Forces along with the Royal Navy and the Royal Air Force. , the British Army comprises 79,380 regular full-time personnel, 4,090 Gurk ...

's SA80 series weapons and L108 and L110 light machine guns. It was phased out and replaced by ACOG and

ELCAN Raytheon ELCAN Optical Technologies, also simply ELCAN ( Ernest Leitz CANada),

sight units during mid-life upgrade programmes. As of March 2019 it is still in use with much of the UK armed forces due to budgetary constraints. It is (or has been) also used by the armies of

Cameroon Cameroon (; french: Cameroun, ff, Kamerun), officially the Republic of Cameroon (french: République du Cameroun, links=no), is a country in west-central Africa. It is bordered by Nigeria to the west and north; Chad to the northeast; the C ...

Oman Oman ( ; ar, عُمَان ' ), officially the Sultanate of Oman ( ar, سلْطنةُ عُمان ), is an Arabian country located in southwestern Asia. It is situated on the southeastern coast of the Arabian Peninsula, and spans the mouth of t ...

Spain , image_flag = Bandera de España.svg , image_coat = Escudo de España (mazonado).svg , national_motto = ''Plus ultra'' (Latin)(English: "Further Beyond") , national_anthem = (English: "Royal March") , i ...

and

Sweden Sweden, formally the Kingdom of Sweden,The United Nations Group of Experts on Geographical Names states that the country's formal name is the Kingdom of SwedenUNGEGN World Geographical Names, Sweden./ref> is a Nordic country located on ...

, in assault rifles such as the Swedish Ak5B and the Spanish CETME LV, although after the replacement of the latter by the

HK G36 The Heckler & Koch G36 (Gewehr 36) is a 5.56×45mm assault rifle designed in the early 1990s by German weapons manufacturer Heckler & Koch as a replacement for the heavier 7.62×51mm G3 battle rifle. It was accepted into service with the ''Bu ...

, those sights have been employed in

Rheinmetall MG3 The MG 3 is a German general-purpose machine gun chambered for the 7.62×51mm NATO cartridge. The weapon's design is derived from the World War II era MG 42 ''Einheitsmaschinengewehr'' (Universal machine gun) that fired the 7.92×57mm Mauser ro ...

machine guns. A similar unit known as the

L2A2 SUIT Sight The SUIT sight is a 4× telescopic sight with tritium-powered illumination, utilised at dusk or dawn. The full name is the L2A2 Sight Unit Infantry Trilux. The sight is not designed as a sniper sight, but as a standard issue infantry sight to im ...

was used on the

L1A1 SLR The L1A1 Self-Loading Rifle, officially "Rifle, 7.62mm, L1A1", also known just as the SLR (Self-Loading Rifle), by the Canadian Army designation C1A1 (C1) or in the US as the "inch pattern" FAL,Especially on the American surplus market. is a Br ...

Reticle

The

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, ...

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 An obelisk (; from grc, ὀβελίσκος ; diminutive of ''obelos'', " spit, nail, pointed pillar") is a tall, four-sided, narrow tapering monument which ends in a pyramid-like shape or pyramidion at the top. Originally constructed by Anc ...

-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 the foreground. The reticle is

-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 Radioactive decay (also known as nuclear decay, radioactivity, radioactive disintegration, or nuclear disintegration) is the process by which an unstable atomic nucleus loses energy by radiation. A material containing unstable nuclei is consid ...

. 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.

Manufacturing

SUSAT is constructed from a one-piece, pressure

die-cast Die casting is a metal casting process that is characterized by forcing molten metal under high pressure into a mold cavity. The mold cavity is created using two hardened tool steel dies which have been machined into shape and work similarly t ...

aluminium Aluminium (aluminum in American and Canadian English) is a chemical element with the symbol Al and atomic number 13. Aluminium has a density lower than those of other common metals, at approximately one third that of steel. I ...

body, into which the eyepiece, objective

lens A lens is a transmissive optical device which focuses or disperses a light beam by means of refraction. A simple lens consists of a single piece of transparent material, while a compound lens consists of several simple lenses (''elements''), ...

and prisms are fitted as assemblies. The SUSAT sight was developed in the

United Kingdom The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Europe, off the north-western coast of the continental mainland. It comprises England, Scotland, Wales and North ...

Royal Armament Research Development Establishment Fort Halstead was a research site of Dstl, an executive agency of the UK Ministry of Defence. It is situated on the crest of the Kentish North Downs, overlooking the town of Sevenoaks, southeast of London. Originally constructed in 1892 as par ...

(RARDE) and is manufactured by United Scientific Instruments and Avimo, now known as

Thales Thales of Miletus ( ; grc-gre, Θαλῆς; ) was a Greek mathematician, astronomer, statesman, and pre-Socratic philosopher from Miletus in Ionia, Asia Minor. He was one of the Seven Sages of Greece. Many, most notably Aristotle, regarded him ...

Optics.

Specifications

SUSAT L9A1 *Overall dimensions: (L x W x H): 145 x 60 x 55 mm *Weight: 417 grams *

Magnification Magnification is the process of enlarging the apparent size, not physical size, of something. This enlargement is quantified by a calculated number also called "magnification". When this number is less than one, it refers to a reduction in siz ...

: 4× *

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. Humans a ...

: 10 degrees (177 mils) *

Objective Objective may refer to: * Objective (optics), an element in a camera or microscope * ''The Objective'', a 2008 science fiction horror film * Objective pronoun, a personal pronoun that is used as a grammatical object * Objective Productions, a Brit ...

diameter: 25,5 mm *

Exit pupil In optics, the exit pupil is a virtual aperture in an optical system. Only rays which pass through this virtual aperture can exit the system. The exit pupil is the image of the aperture stop in the optics that follow it. In a telescope or compoun ...

: 6.375 mm *

Eye relief {{Short description, Optical instrument The eye relief of an optical instrument (such as a telescope, a microscope, or binoculars) is the distance from the last surface of an eyepiece within which the user's eye can obtain the full viewing angle. ...

: 25 mm *Light permeability: >80% *Reticle illumination: Red tritium, glass ampoule *Illumination strength: Adjustable *Tritium ampoule lifetime: 8–12 years *Focus: −0.75 to −1.25

dioptre A dioptre (British spelling) or diopter (American spelling) is a unit of measurement with dimension of reciprocal length, equivalent to one reciprocal metre, 1 dioptre = 1 m−1. It is normally used to express the optical power of a lens or curv ...

s *Operational temperature: −46 to +71

°C The degree Celsius is the unit of temperature on the Celsius scale (originally known as the centigrade scale outside Sweden), one of two temperature scales used in the International System of Units (SI), the other being the Kelvin scale. The ...

*Range Settings: 100 to 600 meters (SUSAT L9A1) or 300 to 800 meters (SUSAT L12A1) in 100 m intervals *NATO Stock Number (NSN): 1240-99-967-0947 (Sight Unit Small Arms Trilux (SUSAT) L12A1)

External links

United Scientific Instruments
��Official website
SIGHT UNIT SMALL ARMS TRILUX (SUSAT)
Firearm sights British Army equipment Military equipment introduced in the 1980s

Use

Reticle

Manufacturing

Specifications

See also

External links