Astronomy with a Budget Telescope

Transcription

1 Astronomy with a Budget Telescope

2 Springer-Verlag London Ltd.

3 Patrick Moore and John Watson Astro omy w h a Budget elescope With 100 Figures, 98 in colour, Springer

4 British Library Cataloguing in Publication Data Moore, Patrick, Astronomy with a budget telescope 1. Telescopes 2. Telescopes - Evaluation I. Title II. Watson, John ISBN ISBN (ebook) DOI / Library of Congress Cataloging-in-Publication Data Moore, Patrick. Astronomy with a budget telescope / Patrick Moore and John Watson. p. cm. Includes bibliographical references and index. ISBN Telescopes. I. Watson, John, II. Title. QB88.M dc 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 2003 Originally published by Springer-Verlag London Limited in 2003 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. Observing the Sun, along with a few other aspects of astronomy, 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 58/ Printed on acid-free paper SPIN

5 Preface We have written this for newcomers to practical astronomy. People who are interested in starting out on practical astronomy often begin by purchasing a budget-priced telescope in a main street store, or may even buy one by mail order. There was a time, not so long ago, when finding a good telescope in your local mall or in a mail order catalogue was pretty well impossible. One of us (Patrick) has been decidedly scathing about such instruments in the past. It is still common for binoculars to be recommended as the best place to start amateur astronomy, and it is true that good binoculars do have some advantages over small telescopes. They are 'handier', and can also be used for mundane activities such as going to the races and bird watching. However, there have been some dramatic improvements in small budget-priced telescopes during the past two or three years. When we set out to write this book, we were both surprised to find how good some of these 'budget' telescopes are! On the other hand, there are still some features that are unsatisfactory. We have done our best to present a balanced view, given the relatively low price. We want to make it doubly clear what we are talking about here: by "budget" we mean those telescopes that can be bought in nonspecialist stores in most cities, and which may also (or may not) be obtained through mail order as well. We mean telescopes that are not manufactured by the mainstream American or - more rarely - Japanese telescope manufacturers. We mean those telescopes that in general don't get advertised in the astronomy magazines. The book was planned by both of us equally, and the writing was shared; basically John has dealt with the telescopes themselves and Patrick with the observational side, though of course there is a great deal of overlap. We hope that the result will be useful to those who are just about to make astronomy a real hobby. Sir Patrick Moore, ebe, FRS (Selsey) John Watson, FRAS (Old Basing) v

6 Contents 1 Introduction... 1 The Good, the Bad and the Ugly How to Buy a Budget Telescope Specifications Accessories Mountings How to Use a Budget Telescope Care and Maintenance Travelling with Your Telescope Setting up an Equatorial Mounting for Visual Use Observing the Solar System The Moon The Sun The Planets The Asteroids Comets Observing the Stars and Galaxies Double Stars Multiple Stars Variable Stars Star Clusters Nebulae Galaxies Photography and Imaging Photographing the Moon Photographing the Sun Photographing the Deep Sky Image Processing Software Sharpness Contrast and Brightness Unsharp Masking Colour Saturation and Hue vii

7 Astronomy with a Budget Telescope 8 Trying Out Some Typical Budget Telescopes Goldline Optical T Tasco Luminova 675x Reflector Telescope Helios 60mm Altazimuth Helios 60mm Equatorial The Next Steps Telescopes The Internet Books and Specialising Photographs: Acknowledgements Bibliography Index viii