The nationally recognized credit-by-exam DSST® program helps students earn college credits for learning acquired outside the traditional classroom such as learning from on-the-job training, reading, or independent study. DSST® tests offer students a cost-effective, time-saving way to use the knowledge they've acquired outside of the classroom to accomplish their education goals. This book provides a general overview of the subjects students will encounter on the exam such as the history of the Science of Astronomy, Astrophysics, Celestial Systems, the Science of Light, Planetary Systems, Nature and Evolution of the Sun and Stars, Galaxies and the Universe. This valuable resource includes: diagnostic pre-test with detailed answer explanations; Assessment Grid designed to help identify areas that need focus; Subject Matter Review proving a general overview of the subjects, followed by a review of the relevant topics and terminology covered on the exam; post-test offering 60 questions all with detailed answer explanations; and key information about the DSST® such as, what to expect on test day and how to register and prepare for the DSST®.