What do people use to study the night sky?
A telescope. They vary from not-so-powerful ones (sold in most techie stores) to very powerful ones that are owned by NASA and other space corporations.
It is the most prominent constellation in the night sky when it is visible, so people use it to admire and observe. It has many wonderful things to see in it, like its nebula. Scientists would use it to study. People also use it to find other stars. Its belt is a very good way of finding the stars Sirius and Aldebaran, as it points to them in opposite directions, Sirius down to the left…
In Latin they reefer to the Night Sky as Dark Sky, In witch it is then abbreviated as ater caelum that is 'Dark Sky' but they use day as '''putesco caelum being day sky. So Dark can be put as '''-ater -atra -atrum I have a Latin speaking friend at work and he says that the dead sky is the correct saying for nighttime so he gave me 'mortuus caelum'. I hope this helps ''''''
I'm assuming you're referring to the cloudy substance in the sky. The substance you see is a combination of Stars and gas. Scientists refer to this as the "Galactic Plain." As far as what tools they use, they tend to use telescopes, probes, etc. However, you can visibly see the Galactic Plain from Earth on a clear night.
The same way you use science to study science - you use what is already known to form theories, hypothesis, and use that knowledge to determine what you will study. You don't want to study something that is already known (unless you want to re-test it), so it helps to use what people have already discovered.