Celestial Shadows

de John Westfall, William Sheehan

Much of what is known about the universe comes from the study of celestial shadows—eclipses, transits, and occultations.  The most dramatic are total eclipses of the Sun, which constitute one of the most dramatic and awe-inspiring events of nature.  Though once a source of consternation or dread, solar eclipses now lead thousands of amateur astronomers and eclipse-chasers to travel to remote points on the globe to savor their beauty and the adrenaline-rush of experiencing totality, and were long the only source of information about the hauntingly beautiful chromosphere and corona of the Sun.   Long before Columbus, the curved shadow of the Earth on the Moon during a lunar eclipse revealed that we inhabit a round world. The rare and wonderful transits of Venus, which occur as it passes between the Earth and the Sun, inspired eighteenth century expeditions to measure the distance from the Earth to the Sun, while the recent transits of 2004 and 2012 were the most widely observed ever--and still produced results of great scientific value.  Eclipses, transits and occultations involving the planets, their satellites, asteroids and stars have helped astronomers to work out the dimensions and shapes of celestial objects—even, in some cases, hitherto unsuspected rings or atmospheres—and now transits have become leading tools for discovering and analyzing planets orbiting other stars. This book is a richly illustrated account of these dramatic and instructive astronomical phenomena. Westfall and Sheehan have produced a comprehensive study that includes historical details about past observations of celestial shadows, what we have learned from them, and how present-day observers—casual or serious—can get the most out of their own observations.