The Amateur Astronomer Sir Patrick Moore The Amateur Astronomer Twelfth Edition With 140 Figures Cover illustration: The Great Nebula in Orion,and lunar eclipse (inset); courtesy of David Hanon,Ringgold,GA. British Library Cataloguing in Publication Data Moore,Patrick The amateur astronomer.–12th ed. 1.Astronomy–Popular works 2.Astronomy–Observers’ manuals I.Title 522 ISBN 1852338784 Library ofCongress Control Number:2005927091 Apart from any fair dealing for the purposes ofresearch 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 ofthe publishers,or in the case ofreprographic reproduc- tion in accordance with the terms oflicences issued by the Copyright Licensing Agency. Enquiries concerning reproduction outside those terms should be sent to the publishers. ISBN 10:1–85233–878–4 ISBN 13:978–1–85233–878–7 Springer Science+Business Media springeronline.com © Springer-Verlag London Limited 2006 The use ofregistered names,trademarks,etc.in this publication does not imply,even in the absence ofa 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 ofthe information contained in this book and cannot accept any legal responsibility or liability for any errors or omissions that may be made.Observing the Sun,along with a few other aspects ofastronomy,can be dangerous.Neither the publisher nor the author accept any legal responsibility or liability for personal loss or injury caused,or alleged to have been caused,by any information or recommendation contained in this book. Typeset by EXPO Holdings,Malaysia Printed in Singapore 58/3830-543210 Printed on acid-free paper SPIN 10987469 Publisher’s Note The 16 star maps shown in Appendix 25 are the original line drawings that Patrick Moore feels are the most suitable as a guide to finding the constellations. The star-map drawings have in the past proved a much easier guide than any printed version ofthem.In this new edition we start with line drawings offamous constellations:Ursa Major and Orion (Maps I and II),before moving on to the more difficult ones later (Maps IV–XVI). Indeed,the detailed maps have been ofgreat service to the more expe- rienced astronomy enthusiasts as well as to the newcomer. We decided that the presentation of the maps was also important. The sizes of the stars are now smaller than in previously published diagrams. This is to allow for more space, particularly in the more detailed diagrams.For somebody starting out,there’s nothing worse than having to find your way through horribly cluttered star maps! So we included the original line drawings with the aim of solving this problem. v Preface to the First Edition Many popular books upon astronomy have been written during the past few years, but most of them cater either for the casual dabbler who is content to learn from the depths ofhis armchair or else for the serious amateur who already knows the main facts.What I have done, or tried to do, is to strike a happy mean. This book has been aimed at the needs ofthe beginner who knows nothing whatsoever,but who is nevertheless anxious to make a start with what equipment he can collect at limited cost. All astronomers,professional or amateur,were beginners once,and all have had to draw upon the experience of those who have learned before them.I feel some diffidence about offering myselfas a guide,but at least I have one qualification:in my early days as an observer I made almost every mistake that it is possible to make! This explains the frequent occurrence ofsuch phrases as “I once saw.…”and “I remem- ber that when I.…” I hope therefore that what I have written may prevent others from falling into the same ridiculous traps. A common fault in popular books is that too much space is devoted to the Moon and planets,and too little to the greater problems of the stars.I am well aware that I have laid myselfopen to precisely this crit- icism, but there is a reason for it. I repeat that I am writing for the amateur who wants to observe; and while the owner of a small tele- scope can make himself extremely useful in the lunar and planetary field,he is rather more limited with regard to stellar problems.I hope, therefore,that the fault may be forgiven. If this book has a use,it will be to the man who works with cheap and limited equipment.I have,however,given a list ofmore advanced works which can be consulted by anyone who wants to go more deeply into the subject. Astronomy is the most satisfying of all hobbies; taken as a class, astronomers are friendly folk.If my book persuades a few people to take a real interest in the heavens,I shall feel that it has been well worth writing. Patrick Moore August 1957 vii Preface to the Twelfth Edition The first edition of The Amateur Astronomerwas published almost half a century ago.Other editions followed,and I hope it is fair to say that they introduced quite a number of people to astronomy.But things have changed since then. In 1957, the average amateur astronomer worked with a modest telescope and a simple camera;his main targets were the planets and some variable stars.Not so today. Electronic devices have largely replaced photographic film,telescopes are computer-controlled and the well-equipped camera can produce results equal to those ofmajor professional observatories a few decades ago.Old-fashioned visual observers are as outdated as dinosaurs. I have to admit that I am a dinosaur, and when I was asked to prepare a new edition ofthis book,I had to make a decision.There was no point in catering for the electronics expert and computer user; others can do that far better than I ever could.So it was better to retain the original pattern,bringing it up to date but not attempting to go further.Ifyou belong to the technology ofthe twenty-first century,this is not the book for you; otherwise – well,I hope that you will find it useful. Sir Patrick Moore Selsey,January 2005 ix Contents 1 Astronomy as a Hobby . . . . . . . . . . . . . . . . . . . . . . . . 1 2 The Unfolding Universe . . . . . . . . . . . . . . . . . . . . . . . 3 3 Telescopes and Observatories . . . . . . . . . . . . . . . . . . . 17 4 The Solar System. . . . . . . . . . . . . . . . . . . . . . . . . . . 31 5 The Sun. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 6 The Moon. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51 7 Occultations and Eclipses. . . . . . . . . . . . . . . . . . . . . . 67 8 Aurorae and the Zodiacal Light . . . . . . . . . . . . . . . . . . 77 9 The Nearer Planets . . . . . . . . . . . . . . . . . . . . . . . . . 83 10 The Outer Planets . . . . . . . . . . . . . . . . . . . . . . . . . . 93 11 Comets and Meteors . . . . . . . . . . . . . . . . . . . . . . . . 105 12 The Stellar Sky . . . . . . . . . . . . . . . . . . . . . . . . . . . 119 13 The Nature ofa Star . . . . . . . . . . . . . . . . . . . . . . . . 127 14 Double Stars . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133 15 Variable Stars. . . . . . . . . . . . . . . . . . . . . . . . . . . . 139 16 Star Clusters and Nebulae. . . . . . . . . . . . . . . . . . . . . 149 17 Galaxies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159 18 Beginnings and Endings. . . . . . . . . . . . . . . . . . . . . . 167 xi xii The Amateur Astronomer APPENDICES 1 Planetary Data . . . . . . . . . . . . . . . . . . . . . . . . . . . 169 2 Planetary Satellites ofMagnitude 14.5 or Brighter . . . . . . . 170 3 Minor Planet Data . . . . . . . . . . . . . . . . . . . . . . . . . 171 4 Elongations and Transits ofthe Inferior Planets . . . . . . . . 172 5 Map ofMars. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 174 6 Jupiter:Transit Work. . . . . . . . . . . . . . . . . . . . . . . . 176 7 Saturn:Intensity Estimates . . . . . . . . . . . . . . . . . . . . 178 8 Forthcoming Eclipses . . . . . . . . . . . . . . . . . . . . . . . 179 9 The Limiting Lunar Detail Visible with Different Apertures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180 10 The Lunar Maps . . . . . . . . . . . . . . . . . . . . . . . . . . 181 11 Some ofthe More Important Annual Meteor Showers . . . . . 193 12 The Constellations . . . . . . . . . . . . . . . . . . . . . . . . . 194 13 Proper Names ofStars. . . . . . . . . . . . . . . . . . . . . . . 197 14 Stars ofthe First Magnitude. . . . . . . . . . . . . . . . . . . . 204 15 Standard Stars for Each Magnitude . . . . . . . . . . . . . . . 205 16 The Greek Alphabet . . . . . . . . . . . . . . . . . . . . . . . . 207 17 Stellar Spectra . . . . . . . . . . . . . . . . . . . . . . . . . . . 208 18 Limiting Magnitudes and Separations for Various Apertures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 209 19 Angular Measure. . . . . . . . . . . . . . . . . . . . . . . . . . 210 20 Test Double Stars. . . . . . . . . . . . . . . . . . . . . . . . . . 211 21 Extinction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 212 22 Bright Novae . . . . . . . . . . . . . . . . . . . . . . . . . . . . 213 Contents xiii 23 Messier’s Catalogue . . . . . . . . . . . . . . . . . . . . . . . . 215 24 The Caldwell Catalogue . . . . . . . . . . . . . . . . . . . . . . 218 25 The Star Maps . . . . . . . . . . . . . . . . . . . . . . . . . . . 221 26 The Observation ofVariable Stars . . . . . . . . . . . . . . . . 273 27 Some Periodical Comets. . . . . . . . . . . . . . . . . . . . . . 285 28 Amateur Observatories . . . . . . . . . . . . . . . . . . . . . . 286 29 Astronomical Societies . . . . . . . . . . . . . . . . . . . . . . 288 30 Bibliography . . . . . . . . . . . . . . . . . . . . . . . . . . . . 289 Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 291