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The invention of the telescope in the 17th century opened up a whole new world. Soon after it appeared, people began to experiment with binocular glasses, a method that gives a different field of view and offers a more portable option. There were three main types of binoculars, or field glasses, developed. The early models were based on the Galilean technique. Porro Prism models were popular in the 1850s and Roof Prism glasses came three decades later. This is an invention that proves that a good idea will stand the test of time.
Magnification, focus and image stabilization have all been improved over the years and binocular glasses are affordable for most people. The choice of glasses is wide and different models suit different activities. Bird watchers rely on binoculars to pursue their interest and hikers and hunters like to carry them too. Some bird watching sites have mounted binoculars for the public's use. Other tourist sites have coin operated glasses, to enable visitors to get a close up of scenic views and landmarks. Binoculars are useful in many circumstances. Even low power opera glasses of 5x are appreciated in the theatre.
Telescopes are expensive, precision instruments and many amateur astronomers opt for the less expensive and more, user friendly binocular glasses. A magnification of between 5 - 8x will be adequate for a good view of the Milky Way, star clusters, planets, bright comets and the craters of the Moon. Binoculars are easy to carry around when star hunting. The less light pollution there is, the better the image will be.
Specialist uses for field glasses have a tradition in the armed forces. The Navy uses hand held binoculars and mounted models. The hand held variety have been developed to maintain a sharp image, despite the pitch and toss of a ship, and are protected against wet conditions. Army personnel have depended on binoculars too for observing enemy movements and difficulties in the terrain. Some models have range meters installed.
In situations, such as boating, humidity can be a problem for the lenses. There are waterproof binocular glasses that are protected against condensation. Pocket binoculars are another option if the priority is the ability to tuck lightweight glasses in a jacket pocket. Leading brands include the European Zeiss and Leica. Japanese models are common, from Nikon, Minolta and Pentax. American manufacturers include Bushnell Performance Optics. Chinese brands are beginning to come on the market too.
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