periscope


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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 (15 cm) in diameter (only a small section projects above the water), and may be withdrawn into the submarine.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.
References in periodicals archive ?
Periscope offers a full spectrum of marketing services to brands, including Arctic Cat, Autotrader, BASF, Best Buy, Bridgestone, Cox Communications, ExxonMobil, Great Clips, Kelley Blue Book, Petco, Target, Toro, Trolli, UnitedHealth Group, Walgreens, Welch's and more.
Last year, Kent - which is based at St Asaph Business Park - signed a PS9 million deal to supply Lockheed Martin's UK division with periscopes and sights for a turret that will feature on the British Army's new 'Ajax' armoured vehicle.
Still, the fact that apps such as Periscope are now supportive of the capability removes entry barriers for users.
Twitter, which is Periscope's parent company, faced questions about a number of acts--from kidnapping to rape to suicide--that were being livestreamed via Periscope.
The purpose of this brief review is to bring this emerging technology to the attention of pathologists, especially with respect to its potential for pathology teaching, describe recent examples in which Periscope has been used as a tool in pathology education, and outline the steps required to use the app.
Periscope is projected to generate annual revenue of about 30 million [yen] ($33.
Periscope on the other hand does not notify followers and videos only appear on the person's Twitter timeline.
Last year, the Bangalore police announced that they would be monitoring people for distress messages on Periscope, and monitor the video feed to help them respond quicker.
Periscope is a Twitter-owned live video app that lets people share and experience live video.
The newspaper recently launched an entertainment magazine, and while Quigg photographs the magazine covers and interviews the subjects, a reporter will Periscope the interaction.
From streaming a fun moment with friends and voicing an opinion, to marching for a cause and citizen journalism, Periscope helps you reach out to a wider audience.
En su Periscope fueron encuerados politicamente divos como Norberto Rivera, quien en medio de las suspicacias de la condena papal que pesa sobre el, se fue de fiesta con algunos personajes que estan en pecado venial, o Carlos Slim con su saco multimillonario a cuestas.