Stellarium is a free open source planetarium showing a realistic sky in 3D, as you would see it with the naked eye, binoculars or a telescope.  Features include: catalogues with more than 200 million stars, constellations for 17 different cultures, images of nebulae.  

Take a look at these lessons/education scenarios for ideas to use in the classroom

Attention Teachers - if you plan to use a lesson/education scenario please give us your feedback afterwards!  Save this link to complete the short evaluation form.  Thank You.

Learn more about these and other Stellarium features