Binoculars

See also: Binocular

One indicates by the term twin a device magnifying Optique binocular intended for the observation of remote objects, made up of two glasses symmetrical rises in parallel.

The interest compared to a single-tube telescope is that the binoculars allow, to a certain extent, to preserve the stereoscopic vision . Certain binoculars of marine with very long range are even designed with an important spacing of the optical axes in entry, so as to improve perception the depth for remote objects.

A contrario , the binoculars, known as of Galileo, which comprise concave eyepieces, and gives, of the objectives, a not reversed image, and has right tubes, without elbow. The spacing of their optical axes being that of the eyes of the observer (variation interpupillaire), they do not increase the effect of relief and are simply conceived for the binocular comfort of the observer. Of low power, they are also described as twin of theater .

Principle

The light enters the optical system by the objectives comprising several lenses, at the end of each tube. The eyepieces being convergent systems, the resulting images would be turned over (high/low) as in a telescope. To allow the observation of the right terrestrial images of it, a optical Véhicule is interposed in the luminous way. Composed of a system of prisms, it offers the advantage of folding the beam of light and of making it possible to reduce the obstruction total of the instrument. Other favors which characterizes this optical apparatus, the optical beams, folded, remain parallel, which makes it possible to increase the variation of the optical axes of the objectives by preserving a difference between the axes of exits equal to that of the eyes of the observer. The consequence is the conservation of the feeling of relief, increased, moreover, by an enlargement of the apparatus higher than the unit.

The whole of the tubes is elaborate of such kind (central mechanical axis) which one can regulate the variation interpupillaire to adjust it from one individual to another. One of the eyepieces is adjustable for the same reasons of difference of visual qualities of the two eyes of the observer.

One will distinguish the military binoculars from current the binoculars known as of navy . For these last, a central serrated roller makes it possible to adapt on an object close by moving the unit to the eyepieces towards the images given by the objectives.

Use

The binoculars are used in the following fields (the list is not exhaustive):
  • operations Military S
  • Ornithology
  • Astronomy amateur
  • monitoring and safety of the public places.
  • assistance and safety at sea.
  • excursions
  • sport and natural
  • to appreciate a spectacle (binoculars of theater, spyglass)

In the first both cases, the objective is to see without being considering; the binoculars are thus equipped with sun visor to avoid the reflections on the external lenses, these reflections could indeed uncover the observer. Moreover, within the military framework, certain binoculars moreover are equipped with devices of amplification with light or conversion with the Infrarouge S into visible light for the Night vision.

In the third case, the precision and the stability of the image are important, the binoculars of astronomies thus are often equipped with an adapter making it possible to assemble them on a support (Trépied).

In Ornithology, the use of a Finnstick is recommended.

Simple: Binoculars

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