All amateur astronomers don't own telescopes. Many use binoculars for observing the wonders of the sky. Even those little toy binoculars that cost $1.99 will make distant objects appear closer, but they aren't powerful enough to use for astronomical observation. If you are going to use binoculars for astronomy, there is some information about binoculars that you need to know before you choose.
The same kind of prism binoculars has been sold for more than a hundred years, and they are still sold today. So you can be sure that "improvements" have been made. You will see "advantages" for each model when you shop for binoculars. You need to remember, however, that each "advantage" has a corresponding "disadvantage" in performance, ease of use, or price. You need to know what "advantages" are to your own best advantage.
1. Power: The power of binoculars is rated by two numbers; 6 x 30, 8 x 50, for example. The first number represents the magnifying power, and the second number represents the diameter of the front lens in millimeters.
2. Aperture: The larger the objective lenses are, the brighter the stars will appear. The 7 x 35s are somewhat all-purpose binoculars, but 7 x 50s will make things brighter.
3. Focusing: Most binoculars have center focus; that is, focus for both eyes is accomplished by turning one central knob. Then the right hand eyepiece can be individually adjusted to account for difference in vision of the eyes. This is a particularly important feature for birdwatchers because birds move. Binoculars for astronomy do not need this feature. All of the bodies that will be observed are at a fixed distance. They aren't going to get closer or further away.
It all comes down to quality vs. price, like always. The best advice is to buy the highest-quality model of the make you have chosen that you can afford.
