Astronomy is the study of the universe. Muggle and magical approaches to astronomy blend together.

Astrology is a subfield of astronomy in the magical world, but not to the Muggles. Observational astronomy focuses on finding objects in space. Theoretical astronomy applies technology and concepts to answer questions about the universe.

Magic tends to interfere with computers, so Muggles have better telescopes.

Magical astronomers are good at applied astronomy which studies how space affects magical life.

To earn an 'O':

Come prepared with a von Rheticus telescope. Study notes. Do all required assignments (there are no due dates, and all are open book). Do extra credit assignments.