Unveiling the Universe: An Introduction to Astronomy

325 Pages·1996·25.17 MB·English

by  J. E. van Zyl BSc

Unveiling the Universe
Springer
London
Berlin
Heidelberg
New York
Barcelona
Budapest
Hong Kong
Milan
Paris
Santa Clara
Singapore
Tokyo
An Introduction to Astronomy
J.E. van Zyl
With 383 Figures
including 45 Colour Plates
Springer
J.E. van Zyl, BSc, BA(Rons), RED
PO Box 35571, Northcliff 2115, Republic of South Africa
Cover illustration: The front cover shows the Orion Nebula, composited from a mosaic of 15 separate fields taken
with NASA's Hubble Space Telescope. C.R. O'Dell (Rice University) and NASA. The back cover also shows Fig. 8.50
(copyright held by NASA); Fig. 10.30; Fig. 14.1 (copyright held by Proff. P.J.E. Peebles, E.J. Roth, M. Seidner and
B. Siebers, made from galaxy counts by C.D. Shane and C.A. Wirtanen); and Fig. 6.5.
ISBN-13: 978-1-4471-1260-0 e-ISBN-13: 978-1-4471-1037-8
DOl: 10.1007/978-1-4471-1037-8
British Library Cataloguing in Publication Data
Van Zyl, Johannes Ebenhaezer
Unveiling the universe: an introduction to astronomy
1. Astronomy
I. Title
520
ISBN-13: 978-1-4471-1260-0
Library of Congress Cataloging-in-Publication Data
Van Zyl, J.E. (Johannes Ebenhaezer), 1913-
[Ontsluier die heelal. Afrikaans]
[Unveiling the universe: an introduction to astronomy 1 J.E. van Zyl.
p. em.
Includes bibliographical references and index.
ISBN-13: 978-1-4471-1260-0
1. Astronomy. I. Title.
QB43.2.V35613 1996 96-13944
520--dc20 CIP
Apart from any fair dealing for the purposes of research or private study, or criticism or review, as permitted under
the Copyright, Designs and Patents Act 1988, this publication may only be reproduced, stored or transmitted, in any
form or by any means, with the prior permission in writing of the publishers, or in the case of reprographic
reproduction in accordance with the terms of licences issued by the Copyright Licensing Agency. Enquiries
concerning reproduction outside those terms should be sent to the publishers.
© Springer-Verlag London Limited 1996
Softcover reprint of the hardcover 1st edition 1996
The use of registered names, trademarks, etc. in this publication does not imply, even in the absence of a specific
statement, that such names are exempt from the relevant laws and regulations and therefore free for general use.
The publisher makes no representation, express or implied, with regard to the accuracy of the information contained
in this book and cannot accept any legal responsibility or liability for any errors or omissions that may be made.
Typeset by EXPO Holdings, Malaysia
58/3830-543210 Printed on acid-free paper
Dedicated to all those who, through their painstaking efforts,
have laboured long and hard to unravel the secrets of
the Universe - they walk the pages of this book
Preface
Many books on general astronomy have been published in recent years, but this one is
exceptional in several respects. It not only provides the complete newcomer to astronomy
with a broad picture, covering all aspects - historical, observational, space research methods,
cosmology - but it also presents enough more advanced material to enable the really
interested student to take matters further.
Astronomy is essentially a mathematical science, but there are many people who are
anxious to take more than a passing interest and yet are not equipped to deal with
mathematical formulae. In this book, therefore, the mathematical sections are deliberately
separated out, so that they can be passed over without destroying the general picture. The
result is that the book will be equally useful to beginners, to more advanced readers, and to
those who really want to go deeply into the subject - for instance at university level.
The whole text is written with admirable clarity, and there are excellent illustrations,
together with extensive appendices which give lists of objects of various types together with
more detailed mathematical explanations. All in all, the book may be said to bridge the gap
between purely popular works and more advanced treatises; as such it deserves a very wide
circulation, and it will undoubtedly run to many future editions.
July 1996 Patrick Moore
vii
Introduction
The purpose of this book is to make the principles of astronomy available to all, so that the
general reader can obtain a good background knowledge. The book can serve as a guide to
amateur astronomers and as a basis for further study.
The methods and calculations employed by astronomers are explained and reduced to
first principles. Actual measurements are used to illustrate the findings and elucidate the
explanations.
The reader need take nothing for granted, because the essential mathematics is not by
passed. In order to facilitate the grasp of the astronomy, Appendices are provided, where the
school mathematics used, is reduced to first principles. The uninitiated reader would do well
to refer to the relevant Appendix where indicated in the text.
Cognate disciplines, such as physics, chemistry, radio-technology, electronics, etc., are not
entered into, for fear of making the book too weighty, although these subjects are the
foundations on which astronomy is based. Electronics and space technology will certainly
continue to enrich astronomy in the future. .
It is hoped that this book will help the general reader gain insight into the wonderful
world of astronomy.
J.E. van Zyl
ix
Ackno~ledgen1ent5
The author thanks his wife Freda for her assistance with the proofreading and the compilation of the Index; and the
following members of the Johannesburg Centre of the Astronomical Society of Southern Africa for their assistance:
K.E. Buchmann, M.D. Overbeek, A.S. Hilton, C. Papadopoulos, G.C. Jacobs, G. Pulik.
Alfred Biehler is thanked for doing the digital processing of the eight star charts in Chapter 1 and Figure 13.1.
The author expresses his gratitude to the undermentioned astronomers and physicists for their painstaking revision
of the text and for their very constructive suggestions. Any remaining shortcomings are entirely due to the author.
Jan Wolterbeek, Senior Lecturer in Astronomy, University of South Africa;
Dr. Chris Koen, South African Astronomical Observatory, Cape Town;
Prof. Liitz Strauss, Professor of Physics, University of Pretoria;
Dr. Chris Engelbrecht, Department of Physics, University of South Africa.
Photographs and Diagrams
The undermentioned Organisations and Persons are thanked for their kind permission to use the images over which
they hold the copyrights:
The National Aeronautics and Space Administration (NASA) and the Jet Propulsion Laboratories, for the following
figures:
5.10,5.12,6.2,6.3,6.6,7.4,7.8,7.35,7.38,8.2,8.3,8.4,8.5, 8.7, 8.9, 8.10, 8.11, 8.12, 8.18, 8.23, 8.27, 8.28, 8.30, 8.31, 8.32,
8.33, 8.34, 8.35, 8.36, 8.37, 8.40, 8.42, 8.44, 8.46, 8.49, 8.50, 8.51, 8.52, 8.53, 8.56, 8.57, 8.58, 8.59, 8.60, 8.61, 8.62, 8.63,
9.20.
The American National Optical Astronomy Observatories, for the following figures:
7.31,9.8,9.12,9.15,9.17,9.18,9.19,11.23,11.2411.35, 12.4, 12.7, 12.12, 12.13, 12.15, 12.18, 13.2, 13.3, 13.4, 13.7, 13.9,
13.12, 13.13, 13.14, 13.15, 13.19, 13.20, 13.24, 13.25, 13.28.
Dr. Hans Vehrenberg, for the following: 7.13a, 10.33, 11.28, 11.36, 11.37, 12.14, 12.19, 13.10, 13.11.
The British Museum, Copyright: 3.1, 3.3, 3.8, 3.17, 3.18, 3.20, 7.1, 10.4.
Hale Observatories/California Institute of Technology: 4.15, 9.10, 9.11, 9.13, 13.16, 13.22.
Space Telescope Science Institute/NASA: 4.26, 7.16, 7.29.
Lowell Obs. Photos: 3.9, 7.14, 10.29.
Yerkes Obs. Photos: 3.10, 5.1, 10.8
UCO/Lick Observatory Images: 6.4, 6.7.
Dr. C.N. Williams, Bedfordview, Transvaal, South Africa: 7.33, 7.34.
Max Planck Institute: 7.21, 7.30.
C. Papadopoulos (N. Akakios): 7.13b, 12.16.
S A Astronomical Observatory: 7.18, 11.32.
Paul E. Roques (Griffith Obs.): 3.19.
National Museum of American History: 3.22.
Sky and Telescope, photo by Dennis di Cicco: 5.14
Sky and Telescope, photo by Paul Hodge: 10.34
xi
xii Acknowledgements
proff. A.S. Murrell, c.P. Knuckles, Mexico State University: 6.1.
Prof. William M. Sinton, Flagstaff: 7.2.
Official US Navy Photograph: 7.15.
C. Nicollier, NASA Johnson Space Centre: 7.26.
Jack Bennett (Mrs. N. Smith): 7.27.
European Southern Observatory: 7.28.
Dr. J.F. McHone, Arizona State University: 7.36, 7.37.
Astromedia, Milwaukee, USA: 7.39.
Cmdr. H. Hatfield, Kent, UK: 8.14.
U.A. Shatalin, Russian Astronautics: 8.22.
Akira Fujii, Japan: 8.25.
M.D. Overbeek, Edenvale, Transvaal: 9.23.
R.T.A. Innes (J.E. Innes, Perth): 10.5.
J. Bartholdi, Haute Provence Obs.: 10.17.
Dr. R.B. Minton, Martin Marietta: 10.24.
Prof. R.A. Fesen, Dartmouth ColI.: 11.26.
Prof. I. Shelton, Toronto University: 11.31.
Royal Observatory, Edinburgh: 11.33.
B. Baldwin (IA U): 11.34.
Warner Swasey Observatory: 11.38.
Harvard College Observatory: 12.3.
Jason Ware, Frisco, Texas, Internet www page http:galaxy photo. com.: 12.11
Zeiss, Oberkochen, Germany: 13.6.
Arecibo Radio Observatory: 13.26.
National Radio Astronomy Obs.: 13.27.
Dr. S. Mitton, Dr. M. Ryle, Cambridge: 13.29.
Proff. P.J.E. Peebles, E.J. Roth, M. Seldner, B. Siebers, Princeton University: 14.1.
Contents
The Visible Night Sky . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
2 The Dawn of Astronomy. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 13
3 The Formulation of Laws ....................................... 19
4 Instruments................................................ 33
5 Fundamental Measurements ..................................... 47
6 Surveying the Planets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 57
7 New Planets, Comets and Meteors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 71
8 Exploring the Solar System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 97
9 The Sun. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 137
10 Stars and Double Stars . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 157
11 Variable Stars. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 195
12 The Milky Way Galaxy ....................................... 221
13 Beyond the Milky Way . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 237
14 From the Big Bang to the Present. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 259
Appendices. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 273
Bibliography. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 315
Index ....................................................... 317
xiii