OBSERVING VARIABLE STARS A guide for the beginner by David H. Levy Cambridge University Press 1989 ISBN 0-521-32112-1 SEEING THE DEEP SKY Telescopic Astronomy Beyond the Solar System by Fred Schaaf John Wiley & Sons, Inc., New York 1992 QB64.S426 1992 522'.2'078--dc20 91-33119 ISBN 0-471-53068-9 ISBN 0-471-53069-7 (pbk.) What do you see when you look through a telescope? Is it the mountains and valleys of a lunar highland, or perhaps a thinly-veiled Jovian storm? Or do you prefer the ghostly light of the distant galaxies, island universes adrift in a sea of space and time? Perhaps you see the fluctuations of stars in our galaxy, stars of all ages whose nightly appearance changes according to some cosmic drumbeat whose rhythm we try to unravel. A variable star is simply a star that changes in brightness. Observing variable stars is both useful to science, and fun. It is a field that needs the observations that dedicated amateurs with binoculars or small telescopes have the time and enthusiasm to make. It will reciprocate as you contribute to it, for the more you observe the more you will learn about your subjects of observation. The purpose of OBSERVING VARIABLE STARS is to inspire you to observe variable stars. Through its pages, Levy shares his enthusiasm for these distant suns that change in brightness. Accordingly the book's approach is to emphasize the observing, and to keep the scientific explanations simple and in the background. When variable star observing became popular in the early years of this century, the prospect of amateur observers adding something to our understanding of nature was the main attraction. In his hugely popular book, FIELD BOOK OF THE SKYS, William Tyler Olcott invited his readers to become part of "the great work of astrophysical research" through a program that could be accomplished from their own back yards. The stellar wind of research changes in direction. Where the careful monitoring of hundreds of long period variable stars once was viewed as the major interest area for variables, today we follow other types as well. In 1920, few astronomers even knew about the stars that have periodic outbursts, the dwarf novae, which today are an important research field. A program for beginners today includes a mixture of Mira-type stars, dwarf novae, eclipsing binary stars and other stars whose light fluctuations are worth noting. Astronomy is a dynamic, evolving science, and the types of variables we add to our programs reflect this changing scene. Getting started can be an experience. The first time Levy spent a night outside trying to estimate the brightness of a variable star, he resolved never to look at one again. The star he chose for that ill-fated night was Chi Cygni, a famous long period variable, which at maximum can often be seen clearly. But on that night, Chi Cygni was nowhere near maximum, and at 13th magnitude, it was completely lost in a sea of very faint Milky Way stars. Levy wasn't sure that Chi Cygni would be very bright that night, but he certainly didn't expect it to be as faint as that. In David Levy's words, "Serious observing is like playing or composing music. To get the most out of these activities takes heart and soul. The mere thought of doing it gives you a pleasant feeling and a twinkle in your eye, but when you first put eye to eyepiece, or finger to keyboard, or pen to paper, your whole being is filled with a special satisfaction. With variables, this joy has the added dimension of being a part of what is happening away from home". SEEING THE DEEP SKY is actually the third book in a series devoted to projects in astronomy. Each book is independent of the others. But to capture anything close to the full range of what astronomy offers, you should take a look at all three. The first book, SEEING THE SKY (Wiley, 1990), covers naked-eye observations of everything from rainbows, twilights, and meteors out to various kinds of stars and the Milky Way. The second work, SEEING THE SOLAR SYSTEM (Wiley, 1991), is devoted to telescopic projects involving the Moon, Sun, planets, comets, and various minor members of our solar system. This third book offers telescope projects about the different kinds of stars, star clusters, nebulae, and galaxies that lie beyond our solar system--in what astronomers have come to call "the deep sky". Along with surveying a selection of deep-sky objects of the kinds much discussed in books and magazines in recent years--nebulae, star clusters, and galaxies--readers will enjoy the projects in this book on objects less often appreciated (but equally deserving): double stars, colorful stars, and stars that are representative of the various spectral types and classes. A large portion of the book is devoted to learning about the nature of the stars themselves (rather than clusters or galaxies of then, or nebulae). Schaaf packs a lot descriptive information in his book boardering on pure inspiration. --- S. Wormley