Wednesday, January 28, 2009

Binoculars for astronomy?



Why would I want to buy a pair of binoculars when I can put that money toward a nice telescope?

Good question! Let's see. A telescope can offer more powerful views than binoculars, you can get a decent telescope for about the same price as some binoculars, and telescopes look more impressive. But binoculars have a couple of advantages that make them worthy of consideration. First of all, they're extremely portable and can be ready to go at a moment's notice. Also, they are binocular, which means you can look through them with both eyes and don't have to squint one eye closed, like you do with a telescope. Many amateur astronomers have both a telescope and a pair of binoculars. Beleive it or not, there are some astronomical objects that can actually look better through a pair of binoculars than they do through the most expensive telescope in the world! Binoculars are usually labelled with two numbers, separated by an "X". The first number represents the magnification and the second number represents the aperture (usually in millimeters). For example, if you come across a pair of binoculars labelled 7X50, that means that objects appear 7 times closer to you than they really are, and the outer objective lenses each measure 50mm in diameter. Since a bigger objective lens means that more light can enter the binoculars, the larger these lenses are, the brighter the objects will appear. Particularly in the case of stargazing, this means that more details can be brought out in the object being viewed. So the best binoculars are those giant 20X80's I saw in the camera shop, right? Not necessarily. The greater the magnification, the more noticeable an unsteady image is. Most people can only hold binoculars steady enough in their hands to support about 10X. There are mounts available to hold binoculars, like the one I built in the photo above

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