periscope

periscope
/per"euh skohp'/, n.
1. an optical instrument for viewing objects that are above the level of direct sight or in an otherwise obstructed field of vision, consisting essentially of a tube with an arrangement of prisms or mirrors and, usually, lenses: used esp. in submarines.
2. a periscopic lens.
[1815-25; back formation from PERISCOPIC]

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Optical instrument (see optics) used in land and sea warfare, submarine navigation, and elsewhere to enable an observer to see the surroundings while remaining under cover, behind armour, or submerged.

A periscope includes two mirrors or reflecting prisms to change the direction of the light coming from the scene observed: the first deflects it down through a vertical tube, the second diverts it horizontally so that the scene can be viewed conveniently.

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▪ optical instrument
 optical instrument used in land and sea warfare, submarine navigation, and elsewhere to enable an observer to see his surroundings while remaining under cover, behind armour, or submerged.

      A periscope includes two mirrors (mirror) or reflecting prisms to change the direction of the light coming from the scene observed: the first deflects it down through a vertical tube, the second diverts it horizontally so that the scene can be viewed conveniently. Frequently there is a telescopic optical system that provides magnification, gives as wide an arc of vision as possible, and includes a crossline or reticle pattern to establish the line of sight to the object under observation. There may also be devices for estimating the range and course of the target in military applications and for photographing through the periscope.

      The simplest type of periscope consists of a tube at the ends of which are two mirrors, parallel to each other but at 45° to the axis of the tube. This device produces no magnification and does not give a crossline image. The arc of vision is limited by the simple geometry of the tube: the longer or narrower the tube, the smaller the field of view. Periscopes of this type were widely used in World War II in tanks (tank) and other armoured vehicles as observation devices for the driver, gunner, and commander. When fitted with a small, auxiliary gunsight telescope, the tank periscope can also be used in pointing and firing the guns. By employing tubes of rectangular cross section, wide, horizontal fields of view can be obtained.

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Universalium. 2010.

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Look at other dictionaries:

  • périscope — [ periskɔp ] n. m. • 1899; zool. 1874; gr. periskopein « regarder autour » ♦ Instrument d optique formé de lentilles et de prismes permettant à un observateur de voir par dessus un obstacle. Périscopes des sous marins, des chars d assaut (⇒… …   Encyclopédie Universelle

  • Periscope — Périscope  Pour l’article homonyme, voir Périscope (homonymie).  Principe général d un périscope …   Wikipédia en Français

  • Periscope — (Афины,Греция) Категория отеля: 4 звездочный отель Адрес: Haritos 22, Kolonaki, Афины, 106 7 …   Каталог отелей

  • Periscope — (Имеровиглион,Греция) Категория отеля: Адрес: Imerovigli, Имеровиглион, 84700, Греция …   Каталог отелей

  • Periscope — Per i*scope, n. [Pref. peri + scope.] A general or comprehensive view. [R.] [1913 Webster] [1913 Webster] …   The Collaborative International Dictionary of English

  • periscope — 1899, formed in English from PERI (Cf. peri ) around + SCOPE (Cf. scope) instrument for viewing. Earlier (1865) a technical term in photography …   Etymology dictionary

  • periscope — ► NOUN ▪ a tube attached to a set of mirrors or prisms, by which an observer in a submerged submarine or behind an obstacle can see things that are otherwise out of sight. DERIVATIVES periscopic adjective …   English terms dictionary

  • periscope — [per′ə skōp΄] n. [ PERI + SCOPE] 1. a periscopic lens 2. an optical instrument consisting of a tube holding a system of lenses and mirrors or prisms, so arranged that a person looking through the eyepiece at one end can see objects reflected at… …   English World dictionary

  • Periscope — For the 1916 French film, see Le périscope. Principle of the periscope. The periscope on the left uses mirrors whereas the right uses prisms. a Mirrors b Prisms c Observer s eye …   Wikipedia

  • Périscope —  Pour l’article homonyme, voir Périscope (homonymie).  Principe général d un périscope …   Wikipédia en Français

  • periscope — n. 1) to lower; raise a periscope 2) (as commands) periscope down; periscope up * * * raise a periscope periscope up (as commands) periscope down to lower …   Combinatory dictionary

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