This book is for amateur astronomers and telescope users who want to move beyond elementary stargazing to more challenging projects. Written by an accomplished amateur astronomer, this indispensable guide to more advanced work is packed with information and lucid explanations. The first section of the book sets out the fundamental principles of practical astronomy, with chapters on telescope optics, the atmosphere, telescope hardware, astrophotography, and electronic imaging. This knowledge is then applied to the full range of celestial bodies accessible by telescope: the solar system, stars and galaxies. For those users who want to move to even greater challenges, chapters on photometry, spectroscopy and radio astronomy bring observational astronomy to a level where data of real scientific value can be acquired.