A Peterson Field Guide to Stars and Planets

The moon is often the most prominent object in the nighttime sky. The
moon is somewhat more than one-quarter the diameter of the earth.
This makes it the largest substantial satellite (moon) in the solar
system in comparison to its parent planet. (Three moons of Jupiter
and one each of Neptune and Saturn are physically larger than our
moon; Pluto's small moon Charon is nearly half Pluto's size.)
The moon orbits the earth every 271?3 days with
respect to the stars. But during that time, the earth and moon have
moved as a system about 1?12 of the way in their yearly orbit around
the sun. So if the moon at a certain point in its orbit is directly
between the earth and the sun, 271?3 days later it has not quite
returned to that point directly between the earth and the sun. The
moon must orbit the earth a bit farther to get back to the same place
with respect to the line between the earth and the sun. The moon
reaches this point in a couple of days, making the synodic period of
the moon equal to 291?2 days. (The synodic period is the interval
between two successive conjunctions -- coming to the same celestial
longitude -- of two celestial bodies, in this case conjunctions of the
moon and sun as observed from the earth.) It is the synodic months
that are taken into account in lunar calendars.

Editor's Note v Acknowledgments vi List of Tables and Appendixes x How to Use This Book 1

 

1. A First Look at the Sky 7 2. A Tour of the Sky 21 3. The Monthly Sky Maps 46 4. The Constellations 126 5. Stars, Nebulae, and Galaxies 144 6. Double and Variable Stars 194 7. Atlas of the Sky 209 8. The Moon 348 9. Finding the Planets 385 10. Observing the Planets 418 11. Comets 455 12. Asteroids 463 13. Meteors and Meteor Showers 467 14. Observing the Sun 474 15. Coordinates, Time, and Calendars 495 16. Telescopes and Binoculars 503

 

Appendixes 512 Glossary 548 Bibliography 557 Index 563

The fourth edition of this best-selling field guide was revised and updated, and each printing brings further updates with the latest information. As of the 16th printing (December 2018), most of the time-sensitive material has been updated for the next decade. Twenty-four color Monthly Sky Maps show exactly what you'll see when facing north or south in the night sky. Fifty-two color Atlas Charts cover the entire sky, including close-ups of areas of special interest, such as the Pleiades and the Orion Nebula. Two dozen pages cover the August 21, 2017, total solar eclipse whose path crossed the continental United States, and other aspects of recent and future solar eclipses.