Scientific American The Amateur Astronomer

286 Pages·2001·2.3 MB·English

by  Shawn Carlson

B u s i n e s s C u l i n a r y A r c h i t e c t u r e
C o m p u t e r G e n e r a l I n t e r e s t
C h i l d r e n L i f e S c i e n c e s B i o g r a p h y
A c c o u n t i n g F i n a n c e M a t h e m a t i c s
H i s t o r y S e l f - I m p r o v e m e n t H e a l t h
E n g i n e e r i n g G r a p h i c D e s i g n
A p p l i e d S c i e n c e s P s y c h o l o g y
I n t e r i o r D e s i g n B i o l o g y C h e m i s t r y
e
WILEY
B O O K
WILEY
JOSSEY-BASS
PFEIFFER
J.K.LASSER
CAPSTONE
WILEY-LISS
WILEY-VCH
WILEY-INTERSCIENCE
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THE AMATEUR
ASTRONOMER
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S
CIENTIFIC
A
MERICAN
THE AMATEUR
ASTRONOMER
Edited by Shawn Carlson
JOHN WILEY & SONS, INC.
New York (cid:2)Chichester (cid:2)Weinheim (cid:2)Brisbane (cid:2)Singapore (cid:2)Toronto
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Copyright © 2001 by Scientific American, Inc. All rights reserved
Published by John Wiley & Sons, Inc.
Illustrations 11-1 and 11-2 copyright © 1990 and 12-1, 25-1, and 26-1 copyright © 2001 by
Michael Goodman
No part of this publication may be reproduced, stored in a retrieval system, or transmitted in
any form or by any means, electronic, mechanical, photocopying, recording, scanning, or
otherwise, except as permitted under Section 107 or 108 of the 1976 United States Copyright
Act, without either the prior written permission of the Publisher, or authorization through
payment of the appropriate per-copy fee to the Copyright Clearance Center, 222 Rosewood
Drive, Danvers, MA 01923, [phone], fax [phone]. Requests to the Publisher for
permission should be addressed to the Permissions Department, John Wiley & Sons, Inc.,
605 Third Avenue, New York, NY 10158-0012, [phone], fax [phone], email:
[email protected].
The publisher and the author have made every reasonable effort to ensure that the experi-
ments and activities in this book are safe when conducted as instructed but assume no
responsibility for any damage caused or sustained while performing the experiments or
activities in the book. Parents, guardians, and/or teachers should supervise young readers
who undertake the experiments and activities in this book.
ISBN 0-471-43699-2
This title is also available in print as ISBN 0-471-38282-5
For more information about Wiley products, visit our Web site at www.Wiley.com
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CONTENTS
Foreword vii
Introduction ix
Part 1 Telescope Making
1. A Simple Telescope for Beginners 3
2. How to Grind, Polish and Test an
Aluminum Telescope Mirror 18
3. The Behavior of the Telescope-maker’s Pitch 28
4. The Dall-Kirkham Telescope 34
5. Principles of Erecting Telescopes 41
6. Powerful Pocket Telescopes 45
7. A Novel Refracting Telescope 49
8. “Off-Axis” Reflecting Telescopes 58
9. Steady Telescope Mountings 65
10. Two Amateur-Built Radio Telescopes 72
Part 2 The Sun
11. How to Observe and Record Sunspots Safely 87
12. Sun of a Gun 95
13. A Coronagraph to View Solar Prominences 99
14. Two Spectroheliographs to Observe the
Solar Disk 105
Part 3 The Earth, Moon, and Satellites
15. A Pendulum That Detects the Earth’s Rotation 121
16. Observing Changes on the Moon 130
17. Curious Amateur Observations of the Moon 135
18. A Pauper’s Guide to Measuring Latitude 143
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vi Contents
19. Precision Geolocation Using Lunar Occultation 147
20. Sundial Potpourri 155
21. How to Study Artificial Satellites 167
22. Predicting Satellite Orbits 176
Part 4 The Planets, Comets, and Stars
23. Amateur Observations of Jupiter 189
24. Predicting Planetary Alignments 194
25. Catch a Comet by Its Tail 203
26. A Picture-Perfect Comet 207
27. A Device to Simulate Planetary Orbits 212
28. An Astrophysical Laboratory in Your Backyard 216
29. An Ocular Spectroscope 225
30. Monitoring Variable Stars 228
Glossary 235
Further Reading 249
Contact List 255
Index 257
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FOREWORD
The Amateur Scientist
The present volume, titled The Amateur Astronomer, is intended to be the
first of a series of books that will derive from the longest running column
in ScientificAmerican,now and for the past 50 or so years known as “The
Amateur Scientist.” The origin of “The Amateur Scientist” goes back to a
column first published in May 1928 and written by Albert G. Ingalls. It was
called then “The Back Yard Astronomer.” His first sentence in that new
column declared: “Here we amateur telescope makers are, more than 3000
of us, gathered together in our own back yard at last.” At the top of the
page is an illustration of the “Back Yard,” with an amateur astronomer at
work, apparently drawn by one Russell W. Porter, then considered a men-
tor of telescope makers throughout the land. Porter declared that the
name of the new column, contracted to “Backyard Astronomer,” conferred
an honorary B.A. degree on all its readers.
In April 1952 the column extended its coverage to include the work of
amateurs in all branches of science, in addition to telescope making and
astronomy. As a fisherman, one of my favorite pieces in July of that year is
on the May fly, to which I have referred a number of frustrated partici-
pants in the sport. Although in 1952 it was virtually impossible to deter-
mine how many people spent leisure time in the pursuit of scientific study
and experiment, one survey in Philadelphia determined that 8000 laymen
in that city, known for some of Benjamin Franklin’s most significant sci-
entific discoveries, were actively engaged in amateur science, and that 700
of the group had made contributions important enough to warrant atten-
tion from various scientific professionals.
The column continued under Mr. Ingalls’ leadership (and under sev-
eral titles mostly related to astronomy) for 27 years, until his retirement in
May 1955, at which time responsibility for the column was turned over to
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viii Foreword
C. L. Stong who continued to widen the breadth and depth of coverage.
Stong died in 1976, and a new columnist, Jearl Walker, was appointed. As
discussed in the following Introduction by Shawn Carlson, the character
of the column changed under the editorship of Walker to focus more on
understanding the principles of physics, his own field, as demonstrated in
everyday life and less on interesting scientific devices within the grasp of
the amateur scientist. Walker retired in 1990, and after a period of dis-
continuous publication, “The Amateur Scientist” was turned over to
Shawn Carlson in 1995.
Happily to all of us at the magazine it is once again attracting an
increasing readership of informed and interested “amateurs,” who can
now supplement their reading of the column and activities stemming
therefrom with an increasing number of Web sites, including our own
(www.sciam.com). Dr. Carlson has our heartfelt gratitude for putting “The
Amateur Scientist” back on course.
I am often asked about the readership of Scientific American—who
these readers are and where their interests lie. My strong suspicion is that
most of these inquiries come from potential readers who for one reason or
another have not yet made the leap. Summarizing our readership in a
brief reply is very difficult, because the population is very large and very
diverse and includes secret clusters of people who would not normally be
identified as amateur scientists. If pressed for a brief reply, however, I
often mention that my image of a reader of Scientific American is someone
whose favorite fantasy on a rainy Saturday afternoon is to read “The Ama-
teur Scientist” and to plan a future experiment.
John J. Hanley
Chairman Emeritus
Scientific American, Inc.
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INTRODUCTION
Scientific Americanmagazine first came off the presses back in 1845. That
makes it the oldest continuously published magazine in the United States.
And “The Amateur Scientist” holds the distinction of being the magazine’s
longest running column; it traces its pedigree back over 70 years. That
surprises most folks. The longest running column in the oldest magazine
in the United States isn’t dedicated to concerns like sex, or scandal, or
style. It’s about good ol’ Yankee ingenuity. It’s devoted to helping everyday
people explore their world and giving them a fighting chance to make orig-
inal discoveries. That fact never ceases to give me hope for our troubled
times. And it is my great honor to write “The Amateur Scientist” today.
Over the years, “The Amateur Scientist” has made a real contribution
to our world. Many working experimentalists first kindled their interest in
science while carrying out a research project described there. And genera-
tions of science teachers have relied on the column for exciting projects to
challenge even their most gifted students. For all their discoveries, and for
helping them spread a passion for science amongst young people, “The
Amateur Scientist” deserves at least a little credit.
You might be surprised to learn that despite the column’s influence
and popularity for more than seven decades, only one anthology of its pro-
jects has ever been published. That book, Science Projects for the Amateur
Scientist,which was edited by C. L. Stong, went out of print in 1972. Since
then, that title has become quite sought-after. A copy in good condition
now sells for well over $100, if you can find one at all. Clearly, it’s high time
some of these classic articles became more accessible to the amateur com-
munity.
It’s fitting that the first new collection of these articles in book form be
devoted to astronomy. Indeed, astronomy owes a great debt to its amateur
explorers. Today thousands of dedicated avocational scientists scrutinize
the night sky with extremely sophisticated instruments. Every year this
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