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Stadimeter
A stadimeter is an optical device for estimating the range to an object of known height by measuring the angle between the top and bottom of the object as observed at the device. It is similar to a sextant, in that the device is using mirrors to measure an angle between two objects but differs in that one ''dials in'' the height of the object. It is one of several types of optical rangefinders, and does not require a large instrument, and so was ideal for hand-held implementations or installation in a submarine's periscope. A stadimeter is a type of analog computer. Development and use The hand held stadimeter was developed by Bradley Allen Fiske (1854–1942), an officer in the United States Navy. It was designed for gunnery purposes, but its first sea tests, conducted in 1895, showed that it was equally useful for fleet sailing and for navigation. It was normally kept on the bridge and used from there and on the bridge wings to keep warships at the proper distance from one ano ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stadimeter MkVMod0
A stadimeter is an optical device for estimating the range to an object of known height by measuring the angle between the top and bottom of the object as observed at the device. It is similar to a sextant, in that the device is using mirrors to measure an angle between two objects but differs in that one ''dials in'' the height of the object. It is one of several types of optical rangefinders, and does not require a large instrument, and so was ideal for hand-held implementations or installation in a submarine's periscope. A stadimeter is a type of analog computer. Development and use The hand held stadimeter was developed by Bradley Allen Fiske (1854–1942), an officer in the United States Navy. It was designed for gunnery purposes, but its first sea tests, conducted in 1895, showed that it was equally useful for fleet sailing and for navigation. It was normally kept on the bridge and used from there and on the bridge wings to keep warships at the proper distance from one ano ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stadiametric Rangefinding
Stadiametric rangefinding, or the stadia method, is a technique of measuring distances with a telescopic instrument. The term stadia comes from a Greek unit of length '' Stadion'' (equal to 600 Greek feet, ''pous'') which was the typical length of a sports stadium of the time. Stadiametric rangefinding is used for surveying and in the telescopic sights of firearms, artillery pieces, or tank guns, as well as some binoculars and other optics. It is still widely used in long-range military sniping, but in many professional applications it is being replaced with microwave, infrared, or laser rangefinding methods. Although much easier to use, electronic rangefinders can give away the shooter's position to a well-equipped adversary, and the need for accurate range estimation existed for much longer than electronic rangefinders small and rugged enough to be suitable for military use. Principle The stadia method is based upon the principle of similar triangles. This means that, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sextant
A sextant is a doubly reflecting navigation instrument that measures the angular distance between two visible objects. The primary use of a sextant is to measure the angle between an astronomical object and the horizon for the purposes of celestial navigation. The estimation of this angle, the altitude, is known as ''sighting'' or ''shooting'' the object, or ''taking a sight''. The angle, and the time when it was measured, can be used to calculate a position line on a nautical or aeronautical chart—for example, sighting the Sun at noon or Polaris at night (in the Northern Hemisphere) to estimate latitude (with sight reduction). Sighting the height of a landmark can give a measure of ''distance off'' and, held horizontally, a sextant can measure angles between objects for a position on a chart. A sextant can also be used to measure the lunar distance between the moon and another celestial object (such as a star or planet) in order to determine Greenwich Mean Time and hence ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 and in the military. They were specially useful for finding the range of a target, such as in naval gunnery and anti-aircraft artillery. The word ''telemeter'' is derived . Designs The first rangefinder telemeter was invented by James Watt in 1769 and put to use in 1771 in surveying canals. Watt called his instrument a micrometer, a term now used with a different meaning in engineering (the micrometer screw gauge). It consisted of two parallel hairs in the focal plane of a telescope eyepiece crossing an upright hair. At the point to be measured, two sliding targets on a surveyor's rod were adjusted to align with the hairs in the telescope. The distance to the rod could then be determined from the distance between the targets on the ro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Periscope
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] |
Analog Computer
An analog computer or analogue computer is a type of computer that uses the continuous variation aspect of physical phenomena such as electrical, mechanical, or hydraulic quantities (''analog signals'') to model the problem being solved. In contrast, digital computers represent varying quantities symbolically and by discrete values of both time and amplitude (digital signals). Analog computers can have a very wide range of complexity. Slide rules and nomograms are the simplest, while naval gunfire control computers and large hybrid digital/analog computers were among the most complicated. Complex mechanisms for process control and protective relays used analog computation to perform control and protective functions. Analog computers were widely used in scientific and industrial applications even after the advent of digital computers, because at the time they were typically much faster, but they started to become obsolete as early as the 1950s and 1960s, although they remaine ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bradley Allen Fiske
Rear Admiral Bradley Allen Fiske (June 13, 1854 – April 6, 1942) was an officer in the United States Navy who was noted as a technical innovator. During his long career, Fiske invented more than a hundred and thirty electrical and mechanical devices, with both naval and civilian uses, and wrote extensively on technical and professional issues; ''The New Yorker'' called him "one of the notable naval inventors of all time." One of the earliest to understand the revolutionary possibilities of naval aviation, he wrote a number of books of important effect in gaining a wider understanding of the modern Navy by the public. For inventing the rangefinder, he was awarded the Elliott Cresson Medal of The Franklin Institute in 1891. Early life and career Fiske was born in Lyons, New York on 13 June 1854 to Rev. William Allen Fiske and Susan Mathews (Bradley) Fiske. He was appointed to the United States Naval Academy from the State of Ohio in 1870, graduating four years later and receiv ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Maneuvering Board
A maneuvering board is an aid to navigation. It is typically a writing surface with a pre-printed compass rose of polar coordinates about a central point, often including adjacent linear scales, and sometimes a time/speed/distance nomogram. With the aid of a marking device, dividers, and parallel rulers, the maneuvering board provides a template for graphical solution of relative motion problems. History Prior to widespread availability of pocket calculators and computers, maneuvering boards were used aboard ships and aircraft to provide rapid solutions to commonly encountered relative motion problems. Availability of RADAR distance information improved solutions obtained with stadimeter estimates. When operating in a formation of ships, navigation personnel were encouraged to add the relative positions of the other ships in formation to their maneuvering boards to clarify station changing problems when orders were received. Applications Where observation of fixed points is ava ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Worm Drive
A worm drive is a gear arrangement in which a worm (which is a gear in the form of a screw) meshes with a worm wheel (which is similar in appearance to a spur gear). The two elements are also called the worm screw and worm gear. The terminology is often confused by imprecise use of the term ''worm gear'' to refer to the worm, the worm wheel, or the worm drive as a unit. The worm drive or "endless screw" was invented by either Archytas of Terentum, Apollonius of Perga, or Archimedes, the last one being the most probable author.Witold Rybczynski, '' One good turn : a natural history of the screwdriver and the screw''. London, 2000. Page 139. The worm drive later appeared in the Indian subcontinent, for use in roller cotton gins, during the Delhi Sultanate in the thirteenth or fourteenth centuries.Irfan Habib''Economic History of Medieval India, 1200–1500'', page 53 Pearson Education Explanation A gearbox designed using a worm and worm wheel is considerably smaller than on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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, weather formations, and terrain. A radar system consists of a transmitter producing electromagnetic waves in the radio or microwaves domain, a transmitting antenna, a receiving antenna (often the same antenna is used for transmitting and receiving) and a receiver and processor to determine properties of the objects. Radio waves (pulsed or continuous) from the transmitter reflect off the objects and return to the receiver, giving information about the objects' locations and speeds. Radar was developed secretly for military use by several countries in the period before and during World War II. A key development was the cavity magnetron in the United Kingdom, which allowed the creation of relatively small systems with sub-meter resolution. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 and in the military. They were specially useful for finding the range of a target, such as in naval gunnery and anti-aircraft artillery. The word ''telemeter'' is derived . Designs The first rangefinder telemeter was invented by James Watt in 1769 and put to use in 1771 in surveying canals. Watt called his instrument a micrometer, a term now used with a different meaning in engineering (the micrometer screw gauge). It consisted of two parallel hairs in the focal plane of a telescope eyepiece crossing an upright hair. At the point to be measured, two sliding targets on a surveyor's rod were adjusted to align with the hairs in the telescope. The distance to the rod could then be determined from the distance between the targets on the ro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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