projecteur
- Domaines
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- éclairagematériel d'éclairage
- marinesignalisation maritime
- Date
Définitions :
((Appareil de)) source lumineuse intense, arc électrique en général, dont les rayons réfléchis par un miroir concave, sont groupés en un faisceau parallèle.
Appareil directif qui permet de concentrer, dans un angle solide déterminé, le faisceau issu d'un foyer lumineux intense (Ex. : projecteur de marine).
Note :
Les premiers projecteurs ont fait leur apparition vers 1875. Dans la marine de guerre, des projecteurs à occultation (volets rabattables commandés par une manette) servent à transmettre des signaux de jour (code morse).
Terme :
- projecteur n. m.
Traductions
-
anglais
Date :Définition
A high-powered light carried on warships at sea, usually mounted as high up as possible, and so fitted that it can be moved in elevation and azimuth as required, and used at night for illumination and by day or night for visual signalling.
Notes :
The source of the light is normally a carbon arc reflected off a parabolic mirror to give a flat beam.
Searchlights were used at sea primarily in night actions, and as a means of signalling in Morse code over comparatively long distances. Before the introduction of radar, it was, along with starshell, the only means of illuminating a target at night, though in doing so it revealed the user's presence to an enemy and gave him a target on which to range and fire. As a means of signalling between ships, it had the advantage of comparatively long range and did not necessarily indicate to an enemy, unless actually within sight, that the vessel using it was in the vicinity, as would a wireless signal.
Today, radar has almost completely replaced the searchlight as a means of target discovery at night, though it still has uses for illumination.Terme :
- searchlight
Terme associé :
- projector