Free Astronomy Text Book
The Astronomical League is pleased to bring you a free introductory text book in astronomy. It covers Planetary Astronomy as well as Stellar and Galactic Astronomy. It is designed to be used in High School Astronomy classes and Astronomy classes at Community Colleges.
It may be distributed widely, may be printed, and you can request a price check of a printed copy at cost from the author, Aaron Clevenson, at email@example.com.
It is available on the Astronomical League website on the Night Sky Tools page: https://www.astroleague.org/navigating-the-night-sky-guides/