Amateur astronomy, also called backyard astronomy and stargazing, is a hobby whose participants enjoy watching the night sky (for sunspots, eclipses, etc.), mainly with portable telescopes. Even though scientific research is not their main goal, many amateur astronomers make a contribution to astronomy by monitoring variable stars, tracking asteroids and discovering transient objects, such as comets. This book is a perfect introduction to Astronomy for amateurs. Written in the 19th century by French Astronomer Camille Flammarion, it is surprisingly complete and up-to-date. It is still used by both professional and amateur astronomers around the world.