Courses

Introduction to Astronomy, MIT (CC BY-NC-SA)

Introduction to Astronomy, Saylor (CC BY)

Journals

Journal of Research of NIST, U.S. Government publication (public domain)

Images

Digital Diagrams for Astronomy (CC BY)

A collection of images created or adapted by Douglas College with a grant from BCcampus Open Education for the Astronomy: OpenStax textbook. Many of the images are available in several formats, with labelled and unlabelled versions to be used for assessment purposes.

Learning Tools

Stellarium (open source): planetarium for your computer

Teach Astronomy

Open Textbooks

General Astronomy, Wikibooks (CC BY-SA)