Teach Yourself VISUALLY Astronomy

257 Pages·2008·29 MB·English

by  Richard Talcott

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Astronomy
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Astronomy
by Richard Talcott
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Teach Yourself VISUALLY™ Astronomy
Copyright © 2009 by Wiley Publishing, Inc., Hoboken, New Jersey. All rights reserved.
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Praise for the Teach Yourself VISUALLY Series
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Credits
Acquisitions Editor
Pam Mourouzis
Development Editor
Mike Thomas
Production Editor
Suzanne Snyder
Copy Editor
Marylouise Wiack
Technical Editor
Frank Reddy
Editorial Manager
Christina Stambaugh
Publisher
Cindy Kitchel
Vice President and Executive Publisher
Kathy Nebenhaus
Interior Design
Kathie Rickard
Elizabeth Brooks
Cover Design
José Almaguer
Dedication
I’d like to dedicate this book to my wife, Evelyn, whose everlasting love makes life a joy and
whose patience and support helped this book become a reality.
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About the Author
Richard Talcott is a senior editor of Astronomy magazine,
the world’s largest magazine devoted to the science and
hobby of astronomy. He has written more than one hundred
feature articles on both the science of astronomy and
observing the night sky.
He edits the “Sky This Month” section at the center of
Astronomy and creates most of the magazine’s star charts.
In collaboration with Joel Harris, he authored Chasing the
Shadow: An Observer’s Guide to Eclipses (Kalmbach Publishing
Co., 1994). He has been an avid observer of the night sky
since the 1960s and has witnessed seven total solar eclipses.
He graduated from Marietta College in Marietta, Ohio, in 1976 with a degree in
Mathematics. After attending graduate school in astronomy at Ohio State University, he
returned to Marietta in the early 1980s as a Lecturer in the Physics Department. Since 1986, he
has worked as an editor at Astronomy.He lives in Waukesha, Wisconsin, with his wife, Evelyn.
Acknowledgments
Although my name appears alone on this book’s cover, I can claim only partial credit for
what you now hold in your hands. I’d first like to thank Marilyn Allen and Bill Liberis for
bringing me to this project. But the true stars of the production are the people at Wiley who
saw this book through from concept to completion. Special thanks go to Pam Mourouzis,
Mike Thomas, and Suzanne Snyder for their efforts to keep me on time and in line.
The words in an astronomy book typically play second fiddle to the photographs accom-
panying them. This one is no different. Although the beauty of the universe is there for all
to see, capturing its splendor takes hard work, dedication, and talent. All the photographers
represented here possess these attributes in abundance. Their abilities are exceeded only by
their generosity in letting me share their images with you. My thanks go to (in alphabetical
order): Anthony Ayiomamitis, Bill and Sally Fletcher, Robert Gendler, Alister Ling, Marvin
Nauman, Jack Newton, Martin Ratcliffe, Rob Ratkowski, Fred Ringwald, Mike Salway,
Mike Simmons, Luca Vanzella, and Oshin Zakarian. Most of the other great images came
from NASA spacecraft — including the Hubble Space Telescope, the Solar and Heliospheric
Observatory, and various missions to the planets. Thanks also go to the Lunar and Planetary
Institute for the close-up images of the Moon, and to the National Optical Astronomy
Observatories and their Advanced Observing Program at Kitt Peak.
My friends and colleagues at Astronomy magazine also played a major role in bringing
this book to fruition. Editor Dave Eicher and senior editors Michael Bakich and Frank
Reddy contributed images, sketches, and valuable feedback. Artist Roen Kelly produced
many of the illustrations that render sometimes difficult concepts understandable. It’s a
pleasure working with each and every one of them. A special thank you to Frank Reddy, who
served as this book’s technical editor. Any mistakes that made it to print are my responsibil-
ity, of course, but Frank’s keen eye kept these to a minimum.
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Table of Contents
1
chapter Introduction to the Sky
Star Names . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
Denebola
Saturn
Astronomical Catalogs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
Understanding Magnitudes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6 Mars LEO
Seeing Color in the Sky . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
Regulus
Dark Adaptation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
Venus
Averted versus Direct Vision . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
Castor
Finding Your Way around the Sky . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10 Pollux
Apparent Sizes and Distances . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12 Alphard
Astronomical Distances . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14
July 1, 2010, 1 hour after sunset
Time in Astronomy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15
Looking west
How Dark Is Your Sky? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16
Party under the Stars . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18
2
chapter Choose the Right Equipment
Naked Eye, Binoculars, or a Telescope? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22
Binoculars . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23
Types of Telescopes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24
Trip the Light Fantastic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25
Telescope Mounts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26
Eyepieces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27
Filters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28
Other Accessories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .29
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3
chapter View the Naked-Eye Sky
Atmospheric Effects on Sunlight . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .32
Sunrise and Sunset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .34
Conjunctions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .38
Constellations and Asterisms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .40
Auroral Lights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .42
Meteors and Fireballs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .46
Treats of the Zodiac . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .50
The Milky Way . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .52
4
chapter Explore the Winter Sky
Learn the Winter Constellations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .56
Discover the Jewels in Taurus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .58
Survey the Wonders in Orion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .62
View the Gems in Gemini . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .66
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5
chapter Explore the Spring Sky
Learn the Spring Constellations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .72
View the Marvels in Leo . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .74
Scan the Delights in Ursa Major . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .78
Go Galaxy-hunting in Virgo . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .82
6
chapter Explore the Summer Sky
Learn the Summer Constellations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .88
Spy the Glittering Clusters in Scorpius . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .90
Encounter the Milky Way in Sagittarius . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .94
Survey Bright Gas Clouds in Cygnus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .98