Telescopes and Techniques: An Introduction to Practical Astronomy

206 Pages·1995·6.616 MB·English

by  Christopher Robert Kitchin BA, BSc, PhD, FRAS (auth.)

Practical Astronomy
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Other titles in this series
The Modern Amateur Astronomer
Patrick Moore (Ed.)
The Observational Amateur Astronomer
Patrick Moore (Ed.)
An Introduction to
Practical Astronomy
c .
R. Ki tc hi n
, Springer
Christopher Robert Kitchin, BA, BSc, PhD, FRAS
University Observatory, University of Hertfordshire,
Bayfordbury, Hertford, Hertfordshire SG 13 8LD, UK
Cover illustration: The Orion Nebula, M42. (Michael Stecker/Galaxy
Picture Library)
ISBN-13: 978-3-540-19898-7 e-ISBN-13: 978-1-4471-3370-4
DOl: 10.1007/978-1-4471-3370-4
British Library Cataloguing in Publication Data
Kitchin, Christopher R.
Telescopes and Techniques: Introduction
to Practical Astronomy. - (Practical
Astronomy Series)
I. Title II. Series
522
Library of Congress Cataloging-in-Publication Data
Kitchin, C.R. (Christopher R.)
Telescopes and techniques: an introduction to practical astronomy
/ Christopher Robert Kitchin.
p. cm.
1. Astronomy. I. Title.
QB43.2.K555 1995 95-10169
522-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 repro
duced, stored or transmitted, in any form or by any means, with the
prior permission in writing of the publishers, or in the case of repro
graphic reproduction in accordance with the terms of licences issued
by the Copyright Licensing Agency. Enquiries concerning reproduc
tion outside those terms should be sent to the publishers.
© Springer-Verlag London Limited 1995
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 Fox Design, Bramley, Guildford, Surrey
34/3830-543210 Printed on acid-free paper
For Jess, Snuffles, Ryan and Badger, and in
memory of Pip, Chalky, Midnight, Sheba, TC,
Satchmo and Monty
Preface
This book arose from the need to introduce first-year
astronomy students at the University of Hertfordshire
to the basic techniques involved in using a telescope
and finding their way around the sky. It soon tran
spired that many aspiring astronomers, not just those
in a university environment, needed similar guidance.
The aim of the book is therefore to be introductory in
the sense that prior knowledge is not assumed, but not
in the usual sense that mathematics is avoided. Anyone
wanting to learn about telescopes, how they work, how
to use them, and how to choose a telescope for their
own use, should find this book helpful. It provides the
information on how to set up a telescope from scratch,
to find objects in the sky, both those bright enough to
be seen with the naked eye, and those for which the
telescope must be set on to the object before it can be
seen. It explains such things as sidereal and solar time,
right ascension and declination, light grasp, aberra
tions etc. in sufficient detail for useful work to be
undertaken. The techniques involved in visual work
with a telescope and imaging with photography and
CCDs are also explained to a similar depth. Ancillary
work and instrumentation such as data processing,
photometry and spectroscopy are outlined in some
what less detail. I hope readers find the book useful
and as interesting as I found it to write.
C.R. Kitchin
1995
vii
Contents
Section 1: Telescopes
Types of Telescope .................. 3
Historical Introduction. . . . . . . . . . . . . . . 3
Modern Instruments. 16
Mounting .... 17
Schmidt Camera 18
2 Telescope Optics . . . . . . . . . . . . . . . 25
Point Sources. . . 25
Extended Images. 29
Objectives. . 31
Eyepieces . . 34
Aberrations. . 40
Mountings . . 44
Observatories and Observing Sites. . 46
Exercises . . . . . . . . . . . . . . . . . . 48
3 Modern Small Telescope Design . . . . . . . . . 49
Introduction . . . . . . . . . . . . . 49
Making Your Own . . . . . . . . . . 51
Commercially Produced Telescopes 54
Section 2: Positions and
Motions
4 Positions in the Sky . . . . . . . . . . . • . . . . 59
Spherical Polar Coordinates. · 59
Celestial Sphere . . . . · 61
Altitude and Azimuth . . · 65
Rotation ... . ..... . .66
Solar and Sidereal Days . · 67
ix
x Contents
Declination and Hour Angle 67
Time ......... . 70
Mean Solar Time 70
Solar Time .... 71
Sidereal Time . . 72
Right Ascension and Declination. 74
Other Coordinate Systems. 77
Exercises ............. . 77
5 Movements of Objects in the Sky . 79
Diurnal Motion. . . . . .... 79
Circumpolar Objects . . . . . 80
Seasons and Annual Motions. . . 81
Movements of the Moon and Planets. 84
Moon. . . . . . . . . . . . . 85
Other Solar System Objects 86
Proper Motion . 88
Precession 90
Parallax. . . . . 92
Aberration . . . 93
Relative Planetary Positions. 94
Position with Respect to the Earth 94
Eclipses . . . . . . . 95
Position in an Orbit. . . . . . . . . 98
Synodic Period . . . . . . . . . . . 99
Exercises. . . . . . . . 100
6 Telescope Mountings. 101
Introduction. . . . . . 101
Equatorial Mountings 102
Alt -Az Mountings . . 105
Making Your Own Mounting 106
Alignment .. . 107
Setting Circles. . . . . . . . . 108
Guiding ........... . 110
Modern Commercial Mountings 111
Section 3: Observing
7 Electromagnetic Radiation 115
Introduction. 115
Intensity .. . 116
Photons .. . 117
Polarisation . 117
Range .... 118
Measurements. 119
Photometry 120
Contents xi
Spectroscopy. 120
Polarimetry 120
8 Visual Observing. 121
Introduction. . . . 121
General and Practical Considerations
and Safety 122
Finding 123
Moon .. 126
Planets. 130
Sun .. 133
Finding. 133
Observing 135
Stars ..... . 137
Nebulae and Galaxies. 143
Day-time Observing 145
False Observations . 147
Exercise ...... . 148
9 Detectors and Imaging. 149
The Eye. . . . . . . . . 149
Charge-Coupled Device Detectors (CCDs) . 151
Image Processing 156
Photography . . . 158
p-i-n Photodiode . 160
Exercise . . . . . 161
10 Data Processing. 163
Introduction. . . 163
Data Reduction . 164
Data Analysis . 167
Exercises ... 167
11 Photometry. 169
Introduction. 169
Photographic Photometry. 169
Absolute Magnitude . . . 171
Wavelength Dependence. 172
UBV System .. 173
Spatial Information. . . 174
Photometers. . . . . . . 174
Observing Techniques . 175
Exercises .... 176
12 Spectroscopy. 177
Introduction. . 177
Spectroscopes. 177
Spectroscopy . 180
xii Contents
Spectral Type. . . 180
Luminosity Class 182
Radial Velocity. . 183
Spectrophotometry . 184
Exercise ......... . 184
Appendix 1: Telescope Manufacturers and
Suppliers ..... 185
Appendix 2: Bibliography. 187
Journals ....... . 187
Star and Other Catalogues, Atlases and
Reference Books. . . . 188
Practical Astronomy Books 188
Introductory Books ..... 189
Appendix 3: National and Major
Astronomical Societies . . 191
Appendix 4: Constellations. . . . . 197
Appendix 5: Answers to Problems . . 199
Index ................. . . . 201