Telescope | Eyepieces

Astronomy or telescope binoculars are quite different than those used for, say bird watching. There is not a "best" pair of binoculars, such as those rated by reviewers. But it is very important that you choose the best pair of binoculars for your specific needs. Binoculars automatically provide you with right-side-up representations as well as providing you with a wider field of scrutiny.

Aperture

When considering a pair of astronomy binoculars you should first understand aperture. It deals with the sizes of the front part of the lens on the binoculars. The bigger the lens, the more light will be collected, and since many astronomical subjects are murky, increased light will allow you to see them much better. You can tell what the aperture is when looking at binoculars since the numbers printed on the binoculars tell you exactly the aperture size.

Thus, when you see a pair of binoculars that proclaims that they are 7X50's means they have a 50mm size aperture. 25X100 size for handheld telescope binoculars would be more than ideal! Any binoculars larger than 25X100 will require a tripod, as they would be too cumbersome to be handheld. Aperture is also referred to as the objective lens diameter and is always the last number printed on the binoculars themselves.

Magnification

The first number printed on the binoculars tells you the magnification. For stargazing you should look for binoculars showing at least 7 times, but no more than 10 times, or again you'll need a tripod for ease of handling.

Exit Pupil

This refers to the width of the light beam that leaves or exits the eyepiece. Figuring this number is quite simple as you simply divide the aperture number by the magnification number. Hence, a 10X50 pair of binoculars would have an exit pupil size of 5 mm.

Because the human eye's average pupil size at night, which is when you'll be using them, is over 7mm, in order for your telescope binoculars to be comfortable when using them you should look for at least a 7mm exit pupil.

Prisms

Binoculars use prisms inside them to make the objects being viewed right side up. There are two different kinds available-roof and Porro. Roof prisms are more compact and may exhibit dimmer images. They are also more expensive. Porro prisms, on the other hand, use differently shaped prisms, are lower priced, but tend to be heavier and bulkier. For telescope binoculars weight and bulk need to be traded off for brighter images.

Conclusion

This article recommended that you purchase binoculars that you find comfortable to use for what you intend to use them for.

After you purchase your telescope binoculars enjoy not only the moon and its lunar mountains, but multiple stars, asteroids, comets, open star clusters, and wide binocular star fields.

By Arnold J. Tadjman
Article Source: EzineArticles.com

Tag: telescope, binocular, stargazing, astronomy, magnification, prism, aperture, moon, telescope binocular, open star cluster