A periscope is an instrument for observation over, around or through an object, obstacle or condition that prevents direct line-of-sight observation from an observer's current position.
In its simplest form, it consists of an outer case with
mirror
A mirror or looking glass is an object that Reflection (physics), reflects an image. Light that bounces off a mirror will show an image of whatever is in front of it, when focused through the lens of the eye or a camera. Mirrors reverse the ...
s at each end set parallel to each other at a 45° angle. This form of periscope, with the addition of two simple lenses, served for observation purposes in the trenches during
World War I
World War I (28 July 1914 11 November 1918), often abbreviated as WWI, was one of the deadliest global conflicts in history. Belligerents included much of Europe, the Russian Empire, the United States, and the Ottoman Empire, with fightin ...
. Military personnel also use periscopes in some
gun turret
A gun turret (or simply turret) is a mounting platform from which weapons can be fired that affords protection, visibility and ability to turn and aim. A modern gun turret is generally a rotatable weapon mount that houses the crew or mechani ...
s and in
armoured vehicles.
More complex periscopes using
prism
Prism usually refers to:
* Prism (optics), a transparent optical component with flat surfaces that refract light
* Prism (geometry), a kind of polyhedron
Prism may also refer to:
Science and mathematics
* Prism (geology), a type of sedimentary ...
s or advanced
fiber optics
An optical fiber, or optical fibre in Commonwealth English, is a flexible, transparent fiber made by drawing glass (silica) or plastic to a diameter slightly thicker than that of a human hair. Optical fibers are used most often as a means to ...
instead of mirrors and providing magnification operate on
submarine
A submarine (or sub) is a watercraft capable of independent operation underwater. It differs from a submersible, which has more limited underwater capability. The term is also sometimes used historically or colloquially to refer to remotely op ...
s and in various fields of science. The overall design of the classical submarine periscope is very simple: two telescopes pointed into each other. If the two telescopes have different individual magnification, the difference between them causes an overall magnification or reduction.
Early examples
Johannes Hevelius
Johannes Hevelius
Some sources refer to Hevelius as Polish:
*
*
*
*
*
*
*
Some sources refer to Hevelius as German:
*
*
*
*
*of the Royal Society
* (in German also known as ''Hevel''; pl, Jan Heweliusz; – 28 January 1687) was a councillor ...
described an early periscope (which he called a "polemoscope") with lenses in 1647 in his work ''
Selenographia, sive Lunae descriptio''
elenography, or an account of the Moon Hevelius saw military applications for his invention.
In 1854,
Hippolyte Marié-Davy invented the first naval periscope, consisting of a vertical tube with two small mirrors fixed at each end at 45°.
Simon Lake
Simon Lake (September 4, 1866 – June 23, 1945) was a Quaker American mechanical engineer and naval architect who obtained over two hundred patents for advances in naval design and competed with John Philip Holland to build the first submarines f ...
used periscopes in his submarines in 1902.
Sir Howard Grubb perfected the device in World War I.
Morgan Robertson
Morgan Andrew Robertson (September 30, 1861 – March 24, 1915) was an American author of short stories and novels, and the self-proclaimed inventor of the periscope.
Early life
Robertson was the son of Andrew Robertson, a ship captain on th ...
(1861–1915) claimed to have tried to patent the periscope: he described a submarine using a periscope in his fictional works.
Periscopes, in some cases fixed to
rifles
A rifle is a long-barreled firearm designed for accurate shooting, with a barrel that has a helical pattern of grooves (rifling) cut into the bore wall. In keeping with their focus on accuracy, rifles are typically designed to be held with bo ...
, served in
World War I
World War I (28 July 1914 11 November 1918), often abbreviated as WWI, was one of the deadliest global conflicts in history. Belligerents included much of Europe, the Russian Empire, the United States, and the Ottoman Empire, with fightin ...
(1914–1918) to enable soldiers to see over the tops of
trenches
A trench is a type of excavation or in the ground that is generally deeper than it is wide (as opposed to a wider gully, or ditch), and narrow compared with its length (as opposed to a simple hole or pit).
In geology, trenches result from erosi ...
, thus avoiding exposure to enemy fire (especially from snipers).
[Willmott, H.P. (2003)
''First World War''. ]Dorling Kindersley
Dorling Kindersley Limited (branded as DK) is a British multinational publishing company specialising in illustrated reference books for adults and children in 63 languages.
It is part of Penguin Random House, a subsidiary of German media co ...
. p. 111.
The
periscope rifle also saw use during the war – this was an infantry rifle sighted by means of a periscope, so the shooter could aim fire the weapon from a safe position below the trench parapet.
During
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 vast majority of the world's countries—including all of the great powers—forming two opposin ...
(1939–1945), artillery observers and officers used specifically-manufactured periscope binoculars with different mountings. Some of them also allowed estimating the distance to a target, as they were designed as
stereoscopic rangefinder
A stereoscopic rangefinder or stereoscopic telemeter is an optical device that measures distance from the observer to a target, using the observer's capability of binocular vision. It looks similar to a coincidence rangefinder, which uses differen ...
s.
Armored vehicle periscopes
Tank
A tank is an armoured fighting vehicle intended as a primary offensive weapon in front-line ground combat. Tank designs are a balance of heavy firepower, strong armour, and good battlefield mobility provided by tracks and a powerful engin ...
s and armoured vehicles use periscopes: they enable drivers, tank commanders, and other vehicle occupants to inspect their situation through the vehicle roof. Prior to periscopes, direct vision slits were cut in the armour for occupants to see out. Periscopes permit view outside of the vehicle without needing to cut these weaker vision openings in the front and side armour, better protecting the vehicle and occupants.
A protectoscope is a related periscopic vision device designed to provide a window in armoured plate, similar to a direct vision slit. A compact periscope inside the protectoscope allows the vision slit to be blanked off with spaced armoured plate. This prevents a potential ingress point for small arms fire, with only a small difference in vision height, but still requires the armour to be cut.
In the context of
armoured fighting vehicle
An armoured fighting vehicle (AFV) is an armed combat vehicle protected by armour, generally combining operational mobility with offensive and defensive capabilities. AFVs can be wheeled or tracked. Examples of AFVs are tanks, armoured car ...
s, such as
tank
A tank is an armoured fighting vehicle intended as a primary offensive weapon in front-line ground combat. Tank designs are a balance of heavy firepower, strong armour, and good battlefield mobility provided by tracks and a powerful engin ...
s, a periscopic vision device may also be referred to as an
episcope. In this context a periscope refers to a device that can rotate to provide a wider field of view (or is fixed into an assembly that can), while an episcope is fixed into position.
Periscopes may also be referred to by slang, e.g. "shufti-scope".
Gundlach and Vickers 360-degree periscopes
An important development, the
Gundlach rotary periscope, incorporated a rotating top with a selectable additional prism which reversed the view. This allowed a tank commander to obtain a 360-degree field of view without moving his seat, including rear vision by engaging the extra prism. This design, patented by
Rudolf Gundlach Rudolf Gundlach (1892–1957) was a Polish military engineer, inventor and tank designer. He headed the design division of the Armored Weapons Technical Research Bureau (''Biuro Badań Technicznych Broni Pancernych''). He held the military rank ...
in 1936, first saw use in the
Polish
Polish may refer to:
* Anything from or related to Poland, a country in Europe
* Polish language
* Poles
Poles,, ; singular masculine: ''Polak'', singular feminine: ''Polka'' or Polish people, are a West Slavic nation and ethnic group, w ...
7-TP
The 7TP (''siedmiotonowy polski'' - 7-tonne Polish) was a Polish light tank of the Second World War. It was developed from the British Vickers 6-ton. A standard tank of the Polish Army during the 1939 Invasion of Poland, its production did not ...
light tank (produced from 1935 to 1939).
As a part of Polish–British pre-
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 vast majority of the world's countries—including all of the great powers—forming two opposin ...
military cooperation, the patent was sold to Vickers-Armstrong where it saw further development for use in
British
British may refer to:
Peoples, culture, and language
* British people, nationals or natives of the United Kingdom, British Overseas Territories, and Crown Dependencies.
** Britishness, the British identity and common culture
* British English, ...
tanks, including the
Crusader,
Churchill
Sir Winston Leonard Spencer Churchill (30 November 187424 January 1965) was a British statesman, soldier, and writer who served as Prime Minister of the United Kingdom twice, from 1940 to 1945 during the Second World War, and again from 1 ...
,
Valentine, and ''
Cromwell
Oliver Cromwell (25 April 15993 September 1658) was an English politician and military officer who is widely regarded as one of the most important statesmen in English history. He came to prominence during the 1639 to 1651 Wars of the Three Ki ...
'' models as the
Vickers Tank Periscope MK.IV
The Gundlach Periscope, usually known under its British designation as Vickers Tank Periscope MK.IV, was a revolutionary invention by Polish engineer Rudolf Gundlach, manufactured for Polish 7TP tanks from the end of 1935 and patented in 1936 as ...
.
The Gundlach-Vickers technology was shared with the
American Army for use in its tanks including the
Sherman
Sherman most commonly refers to:
*Sherman (name), a surname and given name (and list of persons with the name)
** William Tecumseh Sherman (1820–1891), American Civil War General
*M4 Sherman, a tank
Sherman may also refer to:
Places United St ...
, built to meet joint British and US requirements. This saw post-war controversy through legal action: "After the Second World War and a long court battle, in 1947 he, Rudolf Gundlach, received a large payment for his periscope patent from some of its producers."
[
The ]USSR
The Soviet Union,. officially the Union of Soviet Socialist Republics. (USSR),. was a transcontinental country that spanned much of Eurasia from 1922 to 1991. A flagship communist state, it was nominally a federal union of fifteen nationa ...
also copied the design and used it extensively in its tanks, including the T-34
The T-34 is a Soviet medium tank introduced in 1940. When introduced its 76.2 mm (3 in) tank gun was less powerful than its contemporaries while its 60-degree sloped armour provided good protection against Anti-tank warfare, anti-tan ...
and T-70
The T-70 was a light tank used by the Red Army during World War II, replacing both the T-60 scout tank for reconnaissance and the T-50 light infantry tank for infantry support. The T-80 light tank was a more advanced version of the T-70 with ...
. The copies were based on Lend-Lease British vehicles, and many parts remain interchangeable. Germany
Germany,, officially the Federal Republic of Germany, is a country in Central Europe. It is the second most populous country in Europe after Russia, and the most populous member state of the European Union. Germany is situated betwe ...
also made and used copies.[Łukomski, Grzegorz and Stolarski, Rafał E. (1999) ''Nie tylko Enigma... Mjr Rudolf Gundlach (1892–1957) i jego wynalazek'' (Not Only Enigma... Major Rudolf Gundlach (1892–1957) and His Invention), Warsaw-London.]
Periscopic gun-sights
Periscopic sights
A sight is an aiming device used to assist in visually aligning ranged weapons, surveying instruments or optical illumination equipments with the intended target. Sights can be a simple set or system of physical markers that have to be aligne ...
were also introduced during the Second World War. In British use, the Vickers periscope was provided with sighting lines, enabling front and rear prisms to be directly aligned to gain an accurate direction. On later tanks such as the Churchill and Cromwell, a similarly marked episcope provided a backup sighting mechanism aligned with a vane sight on the turret roof.
Later, US-built Sherman tanks and British Centurion
A centurion (; la, centurio , . la, centuriones, label=none; grc-gre, κεντυρίων, kentyríōn, or ) was a position in the Roman army during classical antiquity, nominally the commander of a century (), a military unit of around 80 ...
and Charioteer tanks replaced the main telescopic sight with a true periscopic sight in the primary role. The periscopic sight was linked to the gun itself, allowing elevation to be captured (rotation being fixed as part of rotating turret). The sights formed part of the overall periscope, providing the gunner with greater overall vision than previously possible with the telescopic sight.
Modern specialised AFV periscopes
In modern use, specialised periscopes can also provide night vision. The Embedded Image Periscope (EIP) designed and patented by Kent Periscopes provides standard unity vision periscope functionality for normal daytime viewing of the vehicle surroundings plus the ability to display digital images from a range of on-vehicle sensors and cameras (including thermal and low light) such that the resulting image appears "embedded" internally within the unit and projected at a comfortable viewing positions.
Naval use
Periscopes allow a submarine
A submarine (or sub) is a watercraft capable of independent operation underwater. It differs from a submersible, which has more limited underwater capability. The term is also sometimes used historically or colloquially to refer to remotely op ...
, when submerged at a relatively shallow depth, to search visually for nearby targets and threats on the surface of the water and in the air. When not in use, a submarine's periscope retracts into the hull. A submarine commander in tactical conditions must exercise discretion when using his periscope, since it creates a visible wake (and may also become detectable by radar
Radar is a detection system that uses radio waves to determine the distance (''ranging''), angle, and radial velocity of objects relative to the site. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, w ...
), giving away the submarine's position.
Marie-Davey built a simple, fixed naval periscope using mirrors in 1854. Thomas H. Doughty of the United States Navy
The United States Navy (USN) is the maritime service branch of the United States Armed Forces and one of the eight uniformed services of the United States. It is the largest and most powerful navy in the world, with the estimated tonnage ...
later invented a prismatic version for use in the American Civil War
The American Civil War (April 12, 1861 – May 26, 1865; also known by other names) was a civil war in the United States. It was fought between the Union ("the North") and the Confederacy ("the South"), the latter formed by states th ...
of 1861–1865.
Submarines adopted periscopes early. Captain Arthur Krebs
Arthur Constantin Krebs (16 November 1850 in Vesoul, France – 22 March 1935 in Quimperlé, France) was a French officer and pioneer in automotive engineering.
Life
Collaborating with Charles Renard, he piloted the first fully controll ...
adapted two on the experimental French submarine in 1888 and 1889. The Spanish inventor Isaac Peral
Isaac Peral y Caballero (1 June 1851, in Cartagena – 22 May 1895, in Berlin), was a Spanish engineer, naval officer and designer of the Peral Submarine. He joined the Spanish navy in 1866, and developed the first electric-powered submarine whi ...
equipped his submarine (developed in 1886 but launched on September 8, 1888) with a fixed, non-retractable periscope that used a combination of prisms to relay the image to the submariner. (Peral also developed a primitive gyroscope
A gyroscope (from Ancient Greek γῦρος ''gŷros'', "round" and σκοπέω ''skopéō'', "to look") is a device used for measuring or maintaining orientation and angular velocity. It is a spinning wheel or disc in which the axis of rota ...
for submarine navigation and pioneered the ability to fire live torpedo
A modern torpedo is an underwater ranged weapon launched above or below the water surface, self-propelled towards a target, and with an explosive warhead designed to detonate either on contact with or in proximity to the target. Historically, su ...
es while submerged.)
The invention of the collapsible periscope for use in submarine warfare is usually credited to Simon Lake
Simon Lake (September 4, 1866 – June 23, 1945) was a Quaker American mechanical engineer and naval architect who obtained over two hundred patents for advances in naval design and competed with John Philip Holland to build the first submarines f ...
in 1902. Lake called his device the "omniscope" or "skalomniscope".
modern submarine periscopes incorporate lenses for magnification and function as telescope
A telescope is a device used to observe distant objects by their emission, absorption, or reflection of electromagnetic radiation. Originally meaning only an optical instrument using lenses, curved mirrors, or a combination of both to observe ...
s. They typically employ prisms and total internal reflection
Total internal reflection (TIR) is the optical phenomenon in which waves arriving at the interface (boundary) from one medium to another (e.g., from water to air) are not refracted into the second ("external") medium, but completely reflected b ...
instead of mirrors, because prisms, which do not require coatings on the reflecting surface, are much more rugged than mirrors. They may have additional optical capabilities such as range-finding
A rangefinder (also rangefinding telemeter, depending on the context) is a device used to measure distances to remote objects. Originally optical devices used in surveying, they soon found applications in other fields, such as photography a ...
and targeting. The mechanical systems of submarine periscopes typically use hydraulics
Hydraulics (from Greek: Υδραυλική) is a technology and applied science using engineering, chemistry, and other sciences involving the mechanical properties and use of liquids. At a very basic level, hydraulics is the liquid counter ...
and need to be quite sturdy to withstand the drag through water. The periscope chassis may also support a radio or radar antenna.
Submarines traditionally had two periscopes; a navigation or observation periscope and a targeting, or commander's, periscope. Navies originally mounted these periscopes in the conning tower
A conning tower is a raised platform on a ship or submarine, often armored, from which an officer in charge can conn the vessel, controlling movements of the ship by giving orders to those responsible for the ship's engine, rudder, lines, and gro ...
, one forward of the other in the narrow hulls of diesel-electric submarines. In the much wider hulls of US Navy submarines the two operate side-by-side. The observation scope, used to scan the sea surface and sky, typically had a wide field of view and no magnification or low-power magnification. The targeting or "attack" periscope, by comparison, had a narrower field of view and higher magnification. In World War II and earlier submarines it was the only means of gathering target data to accurately fire a torpedo, since sonar
Sonar (sound navigation and ranging or sonic navigation and ranging) is a technique that uses sound propagation (usually underwater, as in submarine navigation) to navigation, navigate, measure distances (ranging), communicate with or detect o ...
was not yet sufficiently advanced for this purpose (ranging with sonar required emission of an electronic "ping" that gave away the location of the submarine) and most torpedoes were unguided.
21st-century submarines do not necessarily have periscopes. The United States Navy's s and the Royal Navy
The Royal Navy (RN) is the United Kingdom's naval warfare force. Although warships were used by English and Scottish kings from the early medieval period, the first major maritime engagements were fought in the Hundred Years' War against F ...
's s instead use photonics masts, pioneered by the Royal Navy's , which lift an electronic imaging sensor-set above the water. Signals from the sensor-set travel electronically to workstations in the submarine's control center. While the cables carrying the signal must penetrate the submarine's hull, they use a much smaller and more easily sealed—and therefore less expensive and safer—hull opening than those required by periscopes. Eliminating the telescoping tube running through the conning tower also allows greater freedom in designing the pressure hull and in placing internal equipment.
See also
* Coincidence rangefinder
A coincidence rangefinder or coincidence telemeter is a type of rangefinder that uses mechanical and optical principles to allow an operator to determine the distance to a visible object. There are subtypes split-image telemeter, inverted image, ...
* Relay lens
* Rangefinder
A rangefinder (also rangefinding telemeter, depending on the context) is a device used to measure distances to remote objects. Originally optical devices used in surveying, they soon found applications in other fields, such as photography an ...
* Vickers Tank Periscope MK.IV
The Gundlach Periscope, usually known under its British designation as Vickers Tank Periscope MK.IV, was a revolutionary invention by Polish engineer Rudolf Gundlach, manufactured for Polish 7TP tanks from the end of 1935 and patented in 1936 as ...
References
External links
''The Fleet Type Submarine Online: Submarine Periscope Manual''
United States Navy Navpers 16165, June 1979
''Simulation of a Periscope''
a
NTNUJAVA Virtual Physics Laboratory
{{Authority control
Optical devices
British inventions
1902 introductions
Submarine components