Binoculars are 2 mirror-symmetrical telescopes assembled side-by-side and arranged to point accurately in the same direction. This allows the observer to utilize both eyes when viewing distant objects. Compare to a monocular telescope, you do not have to close one eye anymore when using a binocular. It generates a 3-dimensional image with depth perception.



Common optical parameters

Magnification is the proportion of the length of the eyepiece divided fractioned by the central distance of the objective. For instance, a magnification factor of 5 creates an image as if you are 5 times nearer to the object. Most hand-held binocular telescopes have lesser magnifications.

The objective diameter establishes the amount of light that can be accumulated to create the image. It is generally expressed in millimeters. Binoculars are categorized according to magnification x objective diameter (5x50).

Field of view determines the distance in width that is visible at 1,000 yards or how many degrees can be viewed. The type of optical designs used in a binocular dictates the field of view.

Different optical designs

A large number of early binocular telescopes applied the Galilean optics. This type of optical design uses a convex objective and a concave eyepiece lens. One good thing about this type is the upright image exhibited. The drawback is the constricted view and lack of potential to adjust in extremely high magnification.

Porro prism binoculars use a double prism in a Z-shaped pattern to erect the reflection. Italian optician Ignazio Porro patented this discovery in 1854. Its advantage is a shorter binocular length and enhanced depth sensation because of broader spacing of the objectives.

In 1880 Achille Victor Emile Daubresse designed binocular using roof prisms. Majority of roof prism binoculars use either the Schmidt-Pechan prism or Abbe-Koenig prism. Its prisms seldom require realignment for proper collimation.

Practical applications

The field of astronomy has been relying on binocular telescopes for ages. General observation of the sky will be an almost impossible task without the binoculars on the astronomers? hands. Comets, supernovas, and other astronomical phenomenon are now enjoyed even by common people anytime, anywhere in the world.

Tourist spots and destinations have taken advantage of binoculars? applications. Coin-operated binoculars give tourist and visitors a closer observation and view for a couple of minutes.

Binocular telescopes are also very useful to various outdoor activities like hunting, bird watching, or environmental observing. People with such hobbies understand its importance and highly depend on its functionalities. Some activities are not even possible without using a binocular.

The army, navy and air force benefit from binoculars in order to uphold security and safety. During engagement and battles, a binocular can save lives and win fights. It can also track enemies, monitor activities, and prevent unexpected attacks.

Binoculars may have evolved since it was first discovered but its applications remain useful in various circumstances. It is no more a plain gadget or equipment to view objects. Its value and usefulness have been tested for hundreds of years. You can have your own set, like a camera, having one is very handy during travel and recreation.