periscope

periscopeLight enters the top lens of a periscope, reflects off a mirror set at a 45 degree angle, travels down the periscope tube, and reflects off a second mirror, also set at a 45 degree angle. Light that reflects off the second mirror exits through the bottom lens and into the eye of the user.

per·i·scope

P0196700 (pĕr′ĭ-skōp′)n. Any of various tubular optical instruments that contain reflecting elements, such as mirrors and prisms, to permit observation from a position displaced from a direct line of sight.

per′i·scop′ic (-skŏp′ĭk), per′i·scop′i·cal (-ĭ-kəl) adj.

periscope

(ˈpɛrɪˌskəʊp) nany of a number of optical instruments that enable the user to view objects that are not in the direct line of vision, such as one in a submarine for looking above the surface of the water. They have a system of mirrors or prisms to reflect the light and often contain focusing lenses[C19: from Greek periskopein to look around; see peri-, -scope]

per•i•scope

art at periosteum (ˈpɛr əˌskoʊp)

n. an optical instrument for viewing objects in an obstructed field of vision, consisting of a tube with an arrangement of prisms or mirrors and, usu., lenses: used esp. in submarines. [1815–25; back formation from periscopic]

periscopeLight enters the top lens of the periscope, reflects off a mirror set at a 45° angle, travels down the periscope tube, and reflects off a second mirror, also set at a 45° angle. The light that reflects off the second mirror exits through the bottom lens and into the eye of the user.

per·i·scope

(pĕr′ĭ-skōp′) An instrument that has angled mirrors or prisms and allows objects not in the direct line of sight to be seen.

Thesaurus

Noun

periscope - an optical instrument that provides a view of an otherwise obstructed fieldoptical instrument - an instrument designed to aid visionpigboat, submarine, U-boat, sub - a submersible warship usually armed with torpedoes

Translations

潜望镜

periscope

(ˈperiskəup) noun a tube containing mirrors, through which a person can look in order to see things which cannot be seen from the position the person is in, especially one used in submarines when under water to allow a person to see what is happening on the surface of the sea. 潜望镜

periscope

(pĕr`ĭskōp) [Gr.,=view around], instrument to enable a person to see objects not in his direct line of vision or concealed by some intervening body. Its essential parts are a tube, prisms, lenses, mirrors, and an eyepiece. The image is received in one mirror and reflected through the tube with its lenses to a mirror visible to the viewer. Periscopes used in submarines are so arranged that they can be turned to permit a view of the entire horizon, with built-in rangefinders and typically six times magnification. Submarine periscopes are of noncorrosive metal, have tubes up to 30 ft (9.1 m) long and about 6 in. (15 cm) in diameter (only a small section projects above the water), and may be withdrawn into the submarine. Many smaller types of periscopes are used in trenches and tanks. With the development of fiber optics, periscopes (known as cystoscopes or endoscopes) have become useful in medicine.

Periscope

an optical instrument for viewing from such military shelters as trenches and dugouts, from tanks, and from submarines. Many periscopes permit measurement of horizontal and vertical angles on the terrain and also range-finding. The design and optical characteristics of a periscope are determined by its purpose, place of installation, and the depth from which observations are to be made.

The simplest periscope is the vertical type, consisting of a vertical sighting tube and two mirrors. Set at 45° angles to the axis of the tube, the mirrors form an optical system that refracts light rays coming from the observed object and directs them toward the observer’s eye. Periscopes in which right-angle prisms are installed in the tube instead of mirrors are common, as are telescopic lens systems and rotating systems, which can be used to obtain an erect magnified image. The field of vision of a periscope with low magnification (up to 1.5 power) is about 40°; it usually decreases with greater magnification. Certain types of periscopes give panoramic vision.

periscope

[′per·ə‚skōp] (optics) An optical instrument used to provide a raised line of vision where it may not be practical or possible, as in entrenchments, tanks, or submarines; the raised line of vision is obtained by the use of mirrors or prisms within the structure of the item; it may have single or dual optical systems. A thin astigmatic lens which approximates a meniscus shape and has a base curve of ±1.25 diopters.

periscope

An optical instrument using two right angle reflectors in order to allow observation of an object from behind a shield or around an obstruction where direct vision is impossible. It has many applications, especially in the military forces (e.g. in tanks, submarines). See periscopic lens.

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Words related to periscope

noun an optical instrument that provides a view of an otherwise obstructed field

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