Textbook in PDF format
Ian Ridpath, Carole Stott, Giles Sparrow. Astronomy: The Universe, Equipment, Stars and Planets, Monthly Guides (Eyewitness Companions).
Presenting a series of innovative visual manuals on a wide variety of popular subjects, these richly illustrated companions offers detailed cutaway views, maps, specially commissioned photographs, informative captions, and a fact-filled text as they cover the basics of different topics of interest