The Astronomy Study Brief is intended as a quick reference guide to fundamental concepts and processes related to the study of astronomy. This compact guide is the ideal orientation for students enrolled in an introduction to astronomy course. It is also recommended as a review or refresher for lifelong learners interested in attaining a general understanding of astronomy in one short read without having to browse numerous websites or plow through a lot of heavy textbooks. This Study Brief focuses on specific concepts related to the study of astronomy. Quick access to key facts and definitions of important terms are supported by clarifying visuals. In an organized, easy-to-follow format, this Study Brief offers a clear, understandable overview of astronomy. The introduction to this Study Brief defines astronomy and discusses its two main branches. A historical time line is provided that highlights major figures in the field and their contributions. Topics covered include: the solar system, the asteroid belt, stars, planets, galaxies, famous astronomers, and new developments in astronomy. A convenient reference chart displays key facts and details about each of the major planets such as: mass, equatorial diameter, polar diameter, equatorial circumference, moons, orbit distance, orbit period, and surface temperature.