Investing in a good pair of German made binoculars takes a little bit of research, but it is well worth it. Start from these basics and build from here and you should end up with a pair of binoculars that will last you for a long time.When it comes to buying binoculars, what do you need to know? To sum it up:

The binoculars need to have a large objective diameter. Having a large objective diameter increases the field of sight. Putting it in other terms, the larger the diameter, the more light can get into your eye. With more light you will be able to see fainter objects. With binoculars with small objective diameters, you will not be able to get a lot of light into your eye, thus fainter objects will not be visible. Get a pair of binoculars that has a magnification no greater than 7-8. Also find a pair with a proper size exit pupil.Good eye relief is also important.fully multi-coated optics.BAK-4 Porro prisms. Rugged design - Binoculars tend to be taken everywhere and tend to fall an extraordinary amount of time. Having a rugged designed pair of binoculars will help to prolong the useful life of your binoculars.Maybe a couple of other goodies

These are just a foreground matter of facts when starting to look at binoculars. Now, depending on what you will be using the binoculars for will also bring about a few more questions. For example, are you going to use your binoculars in the dark? If so, you may want to consider investing in a pair of night vision binoculars. But, how about if your just looking at the stars. Then a pair of night vision binoculars would not be needed. In this case I would opt for a pair of high power binoculars to bring the stars image closer for better study.
 

Source: Big Porro Binoculars,   Monocular Telescope