When people talk about astronomy, they think about telescopes.
It's as there no real astronomy without the help of a telescope.
The reality is that many astronomical targets can be seen with binoculars.
Quite a few amateur astronomers prefer giant binoculars, instead of telescopes.
Using 2 eyes instead of a single one si one advantage. Another aspect of using binoculars for astronomy is portability. Binoculars are small and can be easy carry in the car and be ready to used in situations where the usage of telescopes is not practical.
Handheld binoculars can be used to track quickly a fast moving object (like a fireball, meteorid, satellite, etc)
There are many binoculars models.
And there are different factors to consider when purchasing binoculars for astronomy:
- aperture (the diameter of the entry lens) - bigger are better but if they are too big/heavy a tripod may be needed. It looks like an optimal size is 9x50 (9 is magnification, 50 represents the size); 8x40 binoculars are used often for astronomy, too
- lens coatings - binoculars with better coatings are more expensive; but they produce a better and sharp image
- tipod adapter - some binoculars can be hooked up to a tripod adapter - this is a nice feature to have - because steady binoculars will show way more detail
- quality of the materials used to make the binoculars - cheap binoculars will be less reliable and more prone to defects
Binoculars can be used to observe many astronomical targets.
In a dark location, they'll show nice detail for Andromeda galaxy (M31).
They're quite helpfull in observing large open clusters like Pleiades (M45), Beehive cluster (M44), Cor Carolis or Taurus constellations.
A few globular clusters can be seen with binoculars, too - but they usually look pretty compressed.
During winter time, Orion nebulae (M42) can be easy seen with binoculars.