Pierre Guillermier and Serge Koutchmy

Total Eclipses: Science, Observations, Myths and Legends

Published in association with

HJ Springer Praxis Publishing PRAXI' Chichester, UK

Table of Contents

Foreword xi Preface xiii Acknowledgements xv Introduction xvii List of illustrations and tables xix List of colour plates xxv

1 THE SUN: OUR LOCAL STAR 1 The Sun as a star 1 Solar radiation 2 The internal structure of the Sun 3

The Sun's chemical composition 6 The photosphere 7 The chromosphere 9 The corona 10 Solar activity 14 Solar cycles 19 Sun-Earth interactions 20

Day and night 20 The tides 21 Climate 21

Space weather 22 The Sun and space missions 25

Skylab 25 Solar Max Mission 27 Ulysses 28 Yohkoh 29 SOHO 30 Cluster 31 TRACE 32

The future and death of the Sun 32

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2 HOW TO OBSERVE THE SUN 35 Observing the photosphere in white light 35

Precautions for solar observing 35 The projection method 37 The Herschel wedge 37 Full-aperture filters 37

The Wolf Number (relative sunspot number) 38 Parameters of photospheric activity 40

Total spot surface calculation 40 Proper motion of spots 40

Observing prominences 41 The Lyot coronagraph 42 The Ha filter 44

'Pro-am' collaboration in solar observation 45 Other solar phenomena 45

The zodiacal light 45 The gegenschein 46 The rainbow 46 The green flash 47 Parhelia (sundogs) 47 Solar halos 47 Polar aurorae 47

Equipment for observing 48 Tripods, altazimuth mounts and equatorial mounts 48 The refractor 48 The reflector 49 The spectroheliograph 49 The coelostat and the heliostat 50

The observing site 52 Solar photography 53 Solar spectroscopy 54

3 ECLIPSES OF THE SUN AND MOON 57 Eclipses and celestial mechanics 57

The motions of the Sun 57 The motions of the Earth 58 The motions of the Moon 58 Celestial motions and eclipses 60 Celestial mechanics and eclipses 61

Eclipses of the Sun 64 The significance of solar eclipses 64 Examples of solar eclipses: total, annular, partial 66

Eclipses of the Moon 70 In the shadow of the Earth 71 The significance of lunar eclipses 72

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Observing a lunar eclipse 74 Eclipse calculation program 77

4 HISTORICAL ECLIPSES AND DISCOVERIES 81 Myths and legends 81 Eclipses of the Moon in history 84

The fall of Constantinople 85 Columbus's lunar eclipse 86

Eclipses of the Sun in history 87 Eclipses in literature 88 The eclipse of Christ's Crucifixion 88 Prince Igor's eclipse 90 Tintin's eclipse 91 Nat Turner's eclipse 93 Eclipses and early discoveries 95 Twentieth-century eclipses 100

Eclipses in flight 126 Why aircraft? 126 Early post-war eclipse flights 128 The aircraft comes into its own 129 The epic flight of Concorde 001 132

Other observing platforms 136 Filming eclipses 139

5 OBSERVING TOTAL ECLIPSES OF THE SUN 141 Preparation and travel 141

Accessibility of the observing site 141 Duration of the event 142 Weather prospects 143

Equipment 144 The eclipse scenario 146 An observing programme for the amateur 148 First contact 149

The Moon meets the Sun 149 The Moon moves across the Sun 149 Falling light levels 150 Fall in temperature 150 Shadow bands 151 Baily's Beads 151

Second contact: totality 151 The shadow arrives 151 Darkness 152 Prominences 152 The chromosphere 153 Stars and planets appear 153

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The solar corona 154 Possible comets 155 Abnormal animal behaviour 155

Third contact 156 The shadow departs 156 Reappearance of a fraction of the solar disk 156

Fourth contact 156 Disappearance of the Moon's disk 156

Amateur observations from an aircraft 157

6 PHOTOGRAPHING ECLIPSES OF THE SUN AND MOON 159 Photographing solar eclipses 159

Preparing for the eclipse 159 Equipment 160 A photographic programme 161 First contact 162 Second contact: totality 163 Third contact 171 Fourth contact 171

Photographing lunar eclipses 172 Equipment 173 A photographic programme 175 Exposure times 176 Drawing lunar eclipses 177 Filming lunar eclipses 178

Appendix A Energy and neutrinos 179 The origin of solar energy 179

Chemical energy 179 Gravitational energy 180 Nuclear energy 180

The neutrino problem 183

Appendix В Eclipses and coronal physics 185 An outline of the physical study of the Sun's corona 186 Morphological analysis of coronal structures 189

Theory 189 Practical aspects 190 Discussion 192

Quantitative photometric analysis of densities 195 General case and homogeneous case 195 The case of large structures 199

Analysis of fine structures 200 Introduction 200 Sheets and discontinuities 201

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Surges, fibrils and plasmoids 203 Temperatures in the corona 205 Conclusions 208 References 209

Appendix С Computer program for solar and lunar eclipse dates 213

Appendix D The eclipse of 11 August 1999 217 The track of the Moon's shadow on 11 August 1999 217 General characteristics 219 Countries through which the track passes 221

Appendix E Eclipses of the Sun and Moon until 2010 227 Total, annular and partial eclipses of the Sun 227 Eclipses of the Moon 228

Addresses and bibliography 231 Magazines and journals 231 Travel agencies offering eclipse trips 232 Some Internet addresses 233 NASA (National Aeronautics and Space Administration) 233 Programs for simulation and image processing 234 Planetaria in the British Isles 235

Bibliography 237 Index 241