It's incredible the number of open source products which could be used in class. One of them is Stellarium. Students need to view and access sources themselves. In this case stellarium proves to be a very good product. Students may view stars at the comfort of their homes.
In technical words it's a planetarium for your computer. It shows a realistic sky in 3D, just like what you see with the naked eye, binoculars or a telescope. It is being used in planetarium projectors. Just set your coordinates and go.
You may download it from here. If you want to use it on your android mobile phone, download it from the google store. Mac/Windows users download it from here.