This book was conceived and written by a group of German amateur observers. Each section was the responsibility of the amateur who had made that aspect of solar astronomy his specialty. The emphasis was on the practical and covers the kind of solar astronomy within the reach of most amateurs.

Soon after publication it was declared by many reviewers as the "standard work" and much correspondence reached the authors from abroad requesting an English translation. In terms of content the basic information in the original German edition will be found here. Where necessary, updating has taken place and errors have been corrected. Numerous passages were revised taking into account the larger, inter-national circle of readers, many pictures have been added and references to German-language literature have been changed, where possible, to appropriate English-language works.

The book is divided into four major parts. Part A describes instruments used in solar astronomy, offers help in making decisions with regard to buying, and provides instructions for those who might build their own instrument. Part B deals with the many different amateur observation possibilities. Part C gives encouragement and help in planning and carrying out expeditions to observe solar eclipses and gives details on observation. Part D is an extensive bibliography especially tailored for the amateur solar astronomer.

Each chapter of the book is self-contained in terms of contents and the reader can turn to those subjects which interest him or her the most. Numerous cross-references are embedded within the text to point the reader to related sections.

Table of contents

    Foreword .................................................................v
    The Sun and Your Safety...................................................1
    Part A Instrumentation....................................................5
        A.1 Choosing a Telescope..............................................7
            A.1.1 Telescopes for White Light Observations.....................7
            A.1.2 Observation of the Sun in Projection........................7
            A.1.3 Observing the Sun with Reflective Objective Filters........12
            A.1.4 Observing the Sun with Eyepiece Filters....................14
            A.1.5 Conclusion.................................................14
        A.2 Telescope Accessories for Sun Viewing............................15
            A.2.1 Solar Projection Screen....................................15
            A.2.2 Spectroscope...............................................17
            A.2.3 Micrometers................................................20
                A.2.3.1 Graticule Eyepiece...................................20
                A.2.3.2 Micrometer Lamella...................................22
        A.3 Filters..........................................................25
            A.3.1 Introduction...............................................25
            A.3.2 Eyepiece Filters...........................................25
            A.3.3 Objective Filters..........................................26
            A.3.4 Helioscopes................................................29
            A.3.5 Summary....................................................34
            A.3.6 Sun Viewer.................................................37
                A.3.6.1 Assembly Instructions................................37
                A.3.6.2 Applications.........................................39
        A.4 Special Instruments..............................................41
            A.4.1 Spectrohelioscope..........................................41
                A.4.1.1 Introduction.........................................41
                A.4.1.2 Spectroheliograph....................................41
                A.4.1.3 Spectrohelioscope....................................42
                A.4.1.4 Operation of the Veio Spectrohelioscope..............42
                A.4.1.5 A Scanning Spectrohelioscope by Young................43
                A.4.1.6 Spectrohelioscope Resolution.........................44
                A.4.1.7 Variants of the Spectrohelioscope....................47
                A.4.1.8 Concluding Remarks...................................48
            A.4.2 Prominence Attachment......................................49
            A.4.3 Prominence Eyepiece........................................53
            A.4.4 Birefringent Filters.......................................57
                A.4.4.1 Introduction.........................................57
                A.4.4.2 Operation............................................57
                A.4.4.3 DayStar Filters......................................59
            A.4.5 Observing the Sun by Radioastronomy........................61
                A.4.5.1 Introduction.........................................61
                A.4.5.2 Telescope Systems....................................63
                A.4.5.3 Designing a Receiver System..........................64
                A.4.5.4 Antenna..............................................64
                A.4.5.5 Antenna Transmission Lines...........................65
                A.4.5.6 Receiver.............................................65
                A.4.5.7 IF Amplifier.........................................66
                A.4.5.8 Integrator...........................................66
                A.4.5.9 Amplifier and Offset Compensator.....................66
                A.4.5.10 Monitor Amplifier...................................68
                A.4.5.11 Power Supply........................................69
                A.4.5.12 Assembly, Commissioning.............................70
                A.4.5.13 Observation Possibilities...........................70
        A.5 Photography......................................................73
            A.5.1 The Photographic Emulsion and its Theory...................73
                A.5.1.1 Characteristic curve.................................74
                A.5.1.2 Spectral sensitivity curve...........................76
                A.5.1.3 Gamma-time curves....................................77
                A.5.1.4 Resolving power......................................77
                A.5.1.5 Schwarzschild behavior...............................78
                A.5.1.6 Summary..............................................79
            A.5.2 Introduction to White Light Photography....................79
            A.5.3 Cameras, Adapters, and Accessories.........................81
                A.5.3.1 Cameras..............................................81
                A.5.3.2 Adapters.............................................83
                A.5.3.3 Accessories..........................................83
            A.5.4 Photographic observations of the Chromosphere..............83
                A.5.4.1 Shooting technique and exposure time.................84
                A.5.4.2 Choosing a photographic emulsion.....................85
            A.5.5 Solar Photography in Violet Light..........................87
            A.5.6 Dark Room Techniques.......................................88
                A.5.6.1 Film Processing......................................88
                A.5.6.2 Paper Printing.......................................90
        A.6 Evaluating Photographs...........................................93
            A.6.1 Microdensitometry/Microphotometry..........................93
            A.6.2 Principle of the Microdensitometer.........................93
            A.6.3 Working Sequence...........................................94
            A.6.4 Data Medium................................................94
            A.6.5 Tips on Preparation and Implementation.....................95
            A.6.6 Microdensitometry Applications.............................95
            A.6.7 Final Observations.........................................97
        A.7 Digital Image Processing.........................................99
            A.7.1 Introduction...............................................99
                A.7.1.1 The Image Generating System.........................100
                A.7.1.2 The Frame Grabber...................................102
                A.7.1.3 The Personal Computer...............................103
                A.7.1.4 Archiving Images....................................103
                A.7.1.5 Image Processing Software...........................104
                A.7.2 Planning an Image Processing System...................106
                A.7.3 Applications..........................................107
        A.8 Recording Solar Structure Movements.............................113
            A.8.1 Introduction..............................................113
            A.8.2 Areas of Application......................................113
            A.8.3 8-mm Movie Cameras........................................114
            A.8.4 Film Type Availability....................................117
            A.8.5 35-mm Cine-camera.........................................117
            A.8.6 Sequential Photographic Prints............................118
                A.8.6.1 Peg Bar.............................................119
                A.8.6.2 Template............................................120
                A.8.6.3 Sequencing the Photographic Prints..................121
                A.8.6.4 Shooting the Animation Sequence.....................121
                A.8.6.5 Calculating Time Periods............................123
            A.8.7 Video.....................................................125

    Part B Solar Observation................................................129
        B.1 Observation.....................................................131
            B.1.1 Observation Program and Note-keeping......................131
                B.1.1.1 Introduction........................................131
                B.1.1.2 Recording Observations..............................131
                B.1.1.3 Observation Programs................................132
            B.1.2 Seeing....................................................134
                B.1.2.1 Introduction........................................134
                B.1.2.2 Appearance..........................................134
                B.1.2.3 Defining Turbulence.................................134
                B.1.2.4 The Causes of Seeing................................135
                B.1.2.5 Daily and Annual Cycles and Other Effects...........136
                B.1.2.6 Place of Observation................................137
                B.1.2.7 Concluding Remarks..................................139
        B.2 Sunspots........................................................141
            B.2.1 The Structure of Sunspots.................................141
                B.2.1.1 Introduction........................................141
                B.2.1.2 Nomenclature........................................141
                B.2.1.3 Pores...............................................142
                B.2.1.4 "Void Areas"........................................142
                B.2.1.5 Umbrae..............................................142
                B.2.1.6 Umbral Dots.........................................143
                B.2.1.7 Bright Points.......................................143
                B.2.1.8 Light Bridges.......................................143
                B.2.1.9 Inner Bright Ring...................................144
                B.2.1.10 Outer Bright Ring..................................144
                B.2.1.11 Penumbra...........................................144
                B.2.1.12 Other Characteristics..............................146
            B.2.2 The Development of Sunspots and Sunspot Groups............146
                B.2.2.1 Typical Development of a Large Area of Activity.....146
                B.2.2.2 Sunspot Classes and Lifetime........................152
                B.2.2.3 The Area of a Group.................................154
                B.2.2.4 Number of Individual Sunspots.......................156
                B.2.2.5 Axis Inclination....................................157
                B.2.2.6 Relationship between the Umbra and Penumbra Areas...158
                B.2.2.7 Brightness of the Umbra.............................158
                B.2.2.8 Rapid Development of Sunspot Groups.................158
            B.2.3 Classification of Sunspots and Sunspot Groups.............161
                B.2.3.1 Waldmeier Classification............................161
                B.2.3.2 McIntosh Classification.............................163
                B.2.3.3 Kunzel Classification...............................167
                B.2.3.4 Area Classification.................................167
                B.2.3.5 Magnetic (Mt. Wilson) Classification................168
                B.2.3.6 Schulze's Umbra Classification......................168
            B.2.4 Measurements of Sunspot Activity..........................170
                B.2.4.1 The Sunspot Number..................................170
                B.2.4.2 Group Number g......................................172
                B.2.4.3 The Individual Spot Number f........................173
                B.2.4.4 Weighting Factor 10 for the Group Number............174
                B.2.4.5 Reduction Factor k..................................175
                B.2.4.6 Influences on the k Factor..........................177
                B.2.4.7 Area Number A.......................................182
                B.2.4.8 The New Area Number According to Beck...............190
                B.2.4.9 The Paderborn Sunspot Number........................192
                B.2.4.10 The Pettis Sunspot Number..........................193
                B.2.4.11 The Activity Area Number...........................193
            B.2.5 Temporal Changes in Sunspot Activity......................198
                B.2.5.1 Wolf Number Observer Networks.......................198
                B.2.5.2 Averaging of Sunspot Numbers with Time..............199
                B.2.5.3 The 11 Year Solar Activity Cycle....................201
                B.2.5.4 The Waldmeier Laws..................................205
                B.2.5.5 The Long Sunspot Cycle..............................210
                B.2.5.6 Long-Term Sunspot Forecasting.......................213
            B.2.6 Naked-Eye Sunspot Observations............................215
                B.2.6.1 Introduction........................................215
                B.2.6.2 Systematic Observations by Unaided Eye..............215
                B.2.6.3 The 11-Year Sunspot Cycle Registered by................
                        Naked-Eye Observations..............................216
                B.2.6.4 Visibility Limit of the Naked-Eye Sunspots..........218
        B.3 Position Determination..........................................221
            B.3.1 Introduction..............................................221
            B.3.2 Observation Methods.......................................222
                B.3.2.1 Heliographic Coordinates............................222
                B.3.2.2 Visual Methods of Determining Positions.............225
                B.3.2.3 Distortion..........................................232
                B.3.2.4 Photographic Observation............................235
                B.3.2.5 Reducing the Position Coordinates to...................
                        Heliographic Coordinates............................239
                B.3.2.6 Applied Position determination, Calculation Example.243
            B.3.3 Suggestions for Evaluation................................246
                B.3.3.1 Mapping the Sun.....................................246
                B.3.3.2 Sunspot Distribution................................248
                B.3.3.3 Extension Measurement of Sunspot Groups.............252
                B.3.3.4 Axis Inclination of Bipolar Sunspot Groups..........256
                B.3.3.5 Inherent Motion in Sunspot Groups...................257
                B.3.3.6 Differential Rotation...............................259
        B.4 Wilson Effect...................................................263
            B.4.1 Historical Background.....................................263
            B.4.2 Present-day Problems......................................265
            B.4.3 Observation Programs for the Amateur......................267
                B.4.3.1 Measure of Strength of the Wilson Effect............267
                B.4.3.2 Visual Observation of the Wilson Effect.............268
                B.4.3.3 Photographic Measurement of the Wilson Effect.......268
            B.4.4 Evaluating Wilson Effect Observations.....................269
                B.4.4.1 Extent of the Umbra and Penumbra....................270
                B.4.4.2 Evaluating the "Crater Mound".......................271
                B.4.4.3 Perspective Correction..............................272
                B.4.4.4 Conclusion..........................................273
        B.5 Light Bridges...................................................275
            B.5.1 Introduction..............................................275
            B.5.2 General Features..........................................275
            B.5.3 The Development of Light Bridges..........................277
            B.5.4 The Classification of Light Bridges.......................280
            B.5.5 Physical Parameters.......................................282
            B.5.6 Suggestions for Research..................................283
                B.5.6.1 Studying Visual Observations........................283
                B.5.6.2 Distribution Statistics.............................284
                B.5.6.3 Position in the Magnetic Field......................285
                B.5.6.4 Light Bridge Granulation............................285
        B.6 Photospheric Faculae............................................287
            B.6.1 Appearance of Faculae.....................................287
            B.6.2 Instruments...............................................288
            B.6.3 Observation...............................................288
            B.6.3.1 Facula Activity.........................................288
            B.6.3.2 Types and Classification of Faculae.....................290
            B.6.3.3 Latitudinal Distribution and Position Measurement.......292
            B.6.3.4 Area....................................................293
            B.6.3.5 Brightness..............................................294
            B.6.3.6 Lifetime of Dot-Shaped Faculae..........................295
            B.6.3.7 Polar Faculae...........................................295
            B.6.3.8 Recording Observations..................................298
        B.7 Granulation.....................................................305
            B.7.1 Introduction..............................................305
            B.7.2 Description...............................................305
            B.7.3 Development and Lifespan..................................307
            B.7.4 Some Other Features.......................................308
            B.7.5 Short Theory of Granulation...............................308
            B.7.6 Options for the Amateur...................................308
        B.8 Amateur Magnetic Field Observation..............................309
            B.8.1 Introduction..............................................309
            B.8.2 Magnetic Field Strength...................................309
            B.8.3 Polarity Distribution.....................................310
            B.8.4 Applications..............................................312
        B.9 Solar Observation in H alpha Light..............................313
            B.9.1 Introduction..............................................313
                B.9.1.1 What is H alpha?....................................315
                B.9.1.2 H Filters...........................................316
                B.9.1.3 What does the frequently encountered expression........
                    "full width at half maximum" (FWHM) mean?...............317
            B.9.2 Choice of Instruments.....................................317
                B.9.2.1 Spectrohelioscope...................................317
                B.9.2.2 Prominence Telescope/Attachment.....................318
                B.9.2.3 Lyot Filter.........................................318
            B.9.3 Chromosphere..............................................321
                B.9.3.1 Historical Background...............................322
                B.9.3.2 Structures of the Quiet Chromosphere................323
                B.9.3.3 Structures of the Active Chromosphere...............324
            B.9.4 Prominences/Filaments.....................................326
                B.9.4.1 Observation Records.................................326
                B.9.4.2 Classifications.....................................329
                B.9.4.3 Types of Prominences According to Völker............337
                B.9.4.4 Observation Programs................................338
                B.9.4.5 Prominence Statistics...............................342
                B.9.4.6 Filament Statistics.................................347
                B.9.4.7 Determining the Position of Chromospheric Phenomena.348
                B.9.4.8 Measuring the Velocities of Prominences.............352
                B.9.4.9 Measuring the Velocity of Filaments.................355
            B.9.5 Flares....................................................359
                B.9.5.1 History.............................................359
                B.9.5.2 The Flare Phenomenon................................360
                B.9.5.3 Light Curve.........................................361
                B.9.5.4 Types of Flares.....................................362
                B.9.5.5 Observation Records.................................363
                B.9.5.6 Classification......................................367
                B.9.5.7 Observation Programs................................368
            B.9.6 Chromospheric Faculae (Plages)............................372
        B.10 The Aurora.....................................................375
            B.10.1 Introduction.............................................375
            B.10.2 Appearance of the Aurora.................................375
            B.10.3 Source of the Aurora.....................................377
            B.10.4 Spectroscopy.............................................380
            B.10.5 Photographing the Aurora.................................381
            B.10.6 Stereoscopic photography.................................382
            B.10.7 Visual Observation.......................................383
            B.10.8 The Radio Aurora.........................................386
            B.10.9 The Magnetic Storm.......................................389
            B.10.10 Plotting of Observations................................391
            B.10.11 Conclusion..............................................393

    Part C Solar Eclipses...................................................395
        C.1 An Introduction to Solar Eclipses...............................397
            C.1.1 Preparing an Expedition to Observe a Solar Eclipse........397
                C.1.1.1 Long-term Preparations..............................397
                C.1.1.2 Medium-term Preparations (about one year...............
                        before the eclipse).................................397
            C.1.2 Visual Observations of Total Solar Eclipses...............400
            C.1.3 Photographic Observations.................................402
                C.1.3.1 White Light Photographs of the Corona...............402
                C.1.3.2 Filming the Corona..................................408
                C.1.3.3 Evaluating the Photographs..........................410
            C.1.4 Photocells................................................411
                C.1.4.1 Optoelectronic Recording of the Solar Corona........411
                C.1.4.2 Optoelectronic Recording of "Shadow Bands"..........412
            C.1.5 Meteorological Observations...............................412
                C.1.6 General Photographic Data.............................413
        C.2 Observable Phenomena............................................415
            C.2.1 Flash Spectrum............................................415
            C.2.2 Corona Shapes and Parameters..............................418
            C.2.3 Polarization of the Corona................................421
            C.2.4 Infrared Corona and Coronal Lines.........................425
                C.2.4.1 569.4 nm............................................427
                C.2.4.2 530.3 nm............................................427
                C.2.4.3 637.4 nm............................................427
            C.2.5 Phenomena in the Solar Corona.............................428
            C.2.6 Movements in the Corona...................................431
            C.2.7 Relationships between the Corona and Prominences..........433
            C.2.8 Historic Eclipses of the Sun..............................436
            C.2.9 Relativistic Light Bending................................438

    Part D A Survey of Solar Astronomy Literature...........................441
        D.1 The Survey......................................................443
            D.1.1 Books For Amateur Solar Observers.........................443
            D.1.2 Books For the Layman Published Before 1950................444
            D.1.3 Books For the Layman Published After 1950.................445
            D.1.4 Monographs for professional astronomers...................447
            D.1.5 Journals About the Sun....................................454

    Bibliography............................................................457

    Appendix A Supplier Sources.............................................503
        A.1 Sources.........................................................503
        A.2 NASA Solar Eclipse Bulletins....................................506
        A.3 Daily Coronal Images............................................506
        A.4 National and International Associations of.........................
            Amateur Solar Observers.........................................507
    Index...................................................................511