Of all the optical instruments, binoculars are widely used by travelers, sports fans, fisherman and hunters.
Binoculars are mounted side by side and aligned to point with accuracy in the same direction. Unlike the single lens telescope, binoculars or binocular telescopes, allows the viewer a greater sense of distance and depth. Binoculars give the users an apparently 3D image.
Binoculars are so designed that the focal length of the lenses is less than is physical length. Larger binoculars can not be held steady hence they are mounted on a support such as tripod. The Large Binocular Telescope, known as LBT is located in Arizona and it produced the “First Light” image from outer space in October 26, 2005.
Coin operated binoculars which are mounted on a pedestal are found in popular tourism spots to help the tourists get a closer view of the sights. By dropping one or two quarters in it, it permits the use of the binoculars for 2 to 3 minutes
A good binocular should produce two sharp images which are uniform, each image having excellent quality, free from geometrical errors or internal reflections and color corrections. Both the images right and left should be identical without any variation in orientation, aberrations and size.
The magnifying power of the binoculars is referred as 7X or 8X which means the object will be magnified 7 or 8 times of its original size. Some binoculars have magnifying capacity in varying degrees. The term 7-21X means starting with 7 times magnification it can reach up to a magnifying power of 21 times. Most commonly used magnifying powers of binoculars are from 6X to 10X increasing in steps of 1.
A good quality binocular can be identified by the popularity and fame of the brand names. By producing high quality optical products, companies such as Leica, Minolta, Pentax, Zeiss, Celestron, Nikon and Swarovski earned a good reputation. As usual we get what we pay for.
Whilst traveling, select a binocular which is light weight, compact and fits easily into the suitcase or shoulder bag. A compact roof prism binocular perfectly fits the bill as a travel companion.
For the budding astronomer, a very high quality and bright binocular with a power rating of 9X, 8X or 7X is required. Make sure that the binoculars can be held steadily while searching and focusing on objects in the sky.
By keeping the binoculars clean, we can make best use of them and get a longer life from them.
Use compressed air in cans to blow the dust off from the lens. Use lens cleaner and lens cloth to remove the grease and dirt from the lenses. Start the cleaning at the center of the lens and gradually swirl towards the rim. Use a soft bristle toothbrush to clean the crevices of the binocular casing and use a slightly damp cloth to wipe the casing.