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Periscope Depth
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 mirrors 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. Military personnel also use periscopes in some gun turrets and in armoured vehicles. More complex periscopes using prisms or advanced fiber optics instead of mirrors and providing magnification operate on submarines 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 described an early ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Periscope Simple
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 mirrors 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. Military personnel also use periscopes in some gun turrets and in Armored car (military), armoured vehicles. More complex periscopes using Prism (optics), prisms or advanced Optical fiber, fiber optics instead of mirrors and providing magnification operate on submarines 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. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trench Warfare
Trench warfare is a type of land warfare using occupied lines largely comprising military trenches, in which troops are well-protected from the enemy's small arms fire and are substantially sheltered from artillery. Trench warfare became archetypically associated with World War I (1914–1918), when the Race to the Sea rapidly expanded trench use on the Western Front starting in September 1914.. Trench warfare proliferated when a revolution in firepower was not matched by similar advances in mobility, resulting in a grueling form of warfare in which the defender held the advantage. On the Western Front in 1914–1918, both sides constructed elaborate trench, underground, and dugout systems opposing each other along a front, protected from assault by barbed wire. The area between opposing trench lines (known as " no man's land") was fully exposed to artillery fire from both sides. Attacks, even if successful, often sustained severe casualties. The development of armoured ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Opaque Projector
The opaque projector, epidioscope, epidiascope or episcope is a device which displays opaque materials by shining a bright lamp onto the object from above. A system of mirrors, prisms and/or imaging lenses is used to focus an image of the material onto a viewing screen. Because they must project the reflected light, opaque projectors require brighter bulbs and larger lenses than overhead projectors. Care must be taken that the materials are not damaged by the heat generated by the light source. Opaque projectors are not as common as the overhead projector. Opaque projectors are typically used to project images of book pages, drawings, mineral specimens, leaves, etc. They have been produced and marketed as artists’ enlargement tools to allow images to be transferred to surfaces such as prepared canvas, or for lectures and discourses. History Swiss mathematician, physicist, astronomer, logician and engineer Leonhard Euler demonstrated an opaque projector around 1756. It could p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 engine; usually their main armament is mounted in a turret. They are a mainstay of modern 20th and 21st century ground forces and a key part of combined arms combat. Modern tanks are versatile mobile land weapons platforms whose main armament is a large-caliber tank gun mounted in a rotating gun turret, supplemented by machine guns or other ranged weapons such as anti-tank guided missiles or rocket launchers. They have heavy vehicle armour which provides protection for the crew, the vehicle's munition storage, fuel tank and propulsion systems. The use of tracks rather than wheels provides improved operational mobility which allows the tank to overcome rugged terrain and adverse conditions such as mud and ice/snow better than wheeled vehicles, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 cars, assault guns, self-propelled guns, infantry fighting vehicles, and armoured personnel carriers. Armoured fighting vehicles are classified according to their characteristics and intended role on the battlefield. The classifications are not absolute; two countries may classify the same vehicle differently, and the criteria change over time. For example, relatively lightly armed armoured personnel carriers were largely superseded by infantry fighting vehicles with much heavier armament in a similar role. Successful designs are often adapted to a wide variety of applications. For example, the MOWAG Piranha, originally designed as an APC, has been adapted to fill numerous roles such as a mortar carrier, infantry fighting vehicle, and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 engine; usually their main armament is mounted in a turret. They are a mainstay of modern 20th and 21st century ground forces and a key part of combined arms combat. Modern tanks are versatile mobile land weapons platforms whose main armament is a large-caliber tank gun mounted in a rotating gun turret, supplemented by machine guns or other ranged weapons such as anti-tank guided missiles or rocket launchers. They have heavy vehicle armour which provides protection for the crew, the vehicle's munition storage, fuel tank and propulsion systems. The use of tracks rather than wheels provides improved operational mobility which allows the tank to overcome rugged terrain and adverse conditions such as mud and ice/snow better than wheeled vehicles, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Periscope Binoculars
Binoculars or field glasses are two refracting telescopes mounted side-by-side and aligned to point in the same direction, allowing the viewer to use both eyes (binocular vision) when viewing distant objects. Most binoculars are sized to be held using both hands, although sizes vary widely from opera glasses to large pedestal-mounted military models. Unlike a (monocular) telescope, binoculars give users a three-dimensional image: each eyepiece presents a slightly different image to each of the viewer's eyes and the parallax allows the visual cortex to generate an impression of depth. Optical designs Galilean Almost from the invention of the telescope in the 17th century the advantages of mounting two of them side by side for binocular vision seems to have been explored. Most early binoculars used Galilean optics; that is, they used a convex objective and a concave eyepiece lens. The Galilean design has the advantage of presenting an erect image but has a narrow field of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Artillery Observer
An artillery observer, artillery spotter or forward observer (FO) is responsible for directing artillery and mortar fire onto a target. It may be a ''forward air controller'' (FAC) for close air support (CAS) and spotter for naval gunfire support (NGSF). Also known as fire support specialist (FiSTer), an artillery observer usually accompanies a tank or infantry maneuver unit. Spotters ensure that indirect fire hits targets which the troops at the fire support base cannot see. Because artillery is an indirect fire weapon system, the guns are rarely in line-of-sight of their target, often located miles away. The observer serves as the eyes of the guns, by sending target locations and if necessary corrections to the fall of shot, usually by radio. More recently, a mission controller for an Army Unmanned Air System (UAS) may also perform this function, and some armies use special artillery patrols behind the enemy's forward elements. Special forces such as the British SAS, US SE ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ernest Brooks (photographer)
Ernest Brooks (23 February 1876 – 1957) was a British photographer, best known for his war photography from the First World War. He was the first official photographer to be appointed by the British military, and produced several thousand images between 1915 and 1918, more than a tenth of all British official photographs taken during the war. His work was often posed and formal, but several of his less conventional images are marked by a distinctive use of silhouette. Before and immediately after the war he worked as an official photographer to the Royal Family, but was dismissed from this appointment and stripped of his official honours in 1925, for reasons that were not officially made public. Early life Brooks was born on 23 February 1876 at Draycott Moor near Faringdon, the son of a farm labourer. He grew up near Windsor, Berkshire, where his father afterwards worked in the Great Park, and as a child frequently encountered members of the Royal Family.Brooks (1921), ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Australian Light Horse
Australian Light Horse were mounted troops with characteristics of both cavalry and mounted infantry, who served in the Second Boer War and World War I. During the inter-war years, a number of regiments were raised as part of Australia's part-time military force. These units were gradually mechanised either before or during World War II, although only a small number undertook operational service during the war. A number of #Legacy, Australian light horse units are still in existence today. Origins The Australian Light Horse was established as the outcome of a debate that took place in military circles in Australia in the late 19th – early 20th centuries concerning the future of mounted troops. The example of the Franco-Prussian War illustrated that the battlefield had become dominated by massed land armies supported by artillery. For Australia the reality was vast spaces with sparse populations making it difficult to consider anything that remotely looked like the European mod ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 different principles and has only one eyepiece. German instruments tended to use the stereoscopic principle while British ones used coincidence. Technical Principle A stereoscopic rangefinder uses two eyepieces and relies on the operator's visual cortex to merge the two images into a single picture. A reference mark is separately inserted into each eyepiece. The operator first adjusts the direction of the range finder so that the fixed mark is centered on the target, and then the prisms are rotated until the mark appears to overlap in the operator's combined view. The range to the target is proportional to the degree of rotation of the prisms.FM 4-15, Coast Artillery Field ManualSeacoast Artillery Fire Control and Position Finding U.S. Government ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
