Astrophysical Techniques C R Kitchin University of Hertfordshire Observatory Third Edition SUB Gottingen 7 210 119 268 99 A 8843 Institute of Physics Publishing Bristol and Philadelphia
Contents Preface Standard symbols xiii xv 1 Detectors 1 1.1 OPTICAL AND INFRARED DETECTION 1 Introduction 1 Detectors 1 Detector types 1 The eye 2 Photomultipliers 7 A detector breviary 18 Charge-coupled devices (CCD) 20 Other types of detectors 30 Photovoltaic cells 30 Photoelectromagnetic detectors 33 Thermocouples 33 Pyroelectric detectors 34 Bolometers 34 Photoconductive cells 35 Phototransistors 36 Charge injection devices (CID) 36 Photographic emulsion 37 Gas cells 37 Television tubes 37 Image intensifiers 37 Golay cell 37 Ultraviolet detectors 37 Future possibilities 38 Noise. 39 Intrinsic noise 39 Signal noise 40 Digitisation 41 vii
viii CONTENTS Telescopes 42 Optical theory 42 Telescope designs 62 Exercises ' 90 1.2 RADIO AND MICROWAVE DETECTION 91 Introduction 91 Detectors and receivers 92 Radio telescopes 97 Construction 105 Exercises 107 1.3 X-RAY AND GAMMA-RAY DETECTION 107 Introduction 107 Detectors 109 Geiger counters 109 Proportional counters 110 Scintillation detectors 111 Gas scintillation proportional counters 112 Charge coupled devices 112 Compton interaction detectors 113 Spark detectors 113 Cerenkov detectors 113 Solid state detectors 113 MicroChannel plates 114 Nuclear emulsions 115 Shielding 116 Imaging 116 Collimation 117 Coincidence detectors 120 Occultation 120 Reflecting telescopes 120 Resolution and image identification 125 Spectroscopy 126 Grating spectrometers 126 Bragg spectrometers 127 Polarimetry 129 Observing platforms 130 1.4 COSMIC RAY DETECTORS 131 Background 131 Detectors 131 Real-time methods 132 Residual track detectors 138 Indirect detectors 143 Arrays 144
CONTENTS ix Correction factors 145 Atmospheric effects. 145 Solar effects 146 - Terrestrial magnetic field ' 146 Exercises 147 1.5 NEUTRINO DETECTORS 149 Background 149 Chlorine 37 detectors 151 Water-based detectors 153 Gallium-based detectors 155 Other types of detectors 155 Direct interaction type detectors 155 Indirect interaction type detectors 156 Geological detectors 156 Scattering detectors 157 Exercises 157 1.6 GRAVITATIONAL RADIATION 158 Introduction 158 Detectors 160 Direct resonant detectors 160 Direct, non-resonant detectors 161 Indirect detectors 163 Exercises 164 2 Imaging 165 2.1 THE INVERSE PROBLEM 165 Deconvolution 166 2.2 PHOTOGRAPHY 170 Introduction 170 Structure of the photographic emulsion 171 The photographic image 174 Processing 182 Hypersensitisation 185 Temperature effects 186 Liquid bathing effects 186 Gas immersion effects 186 Pre-exposure 187 Post-exposure techniques 187 Faint image contrast enhancement 188 Autoradiographic image retrieval 188 Film types '. 188 Techniques of astronomical photography 189 Analysis of photographic images 190 Special applications 191
CONTENTS 2.3 ELECTRONIC IMAGING Introduction Arrays Television and related systems Image intensifies Magnetically focused image intensifies Electrostatically focused image intensifies Proximity focused image intensifies Cascades Recording Photon counting imaging systems Electronographic cameras 2.4 SCANNING 2.5 INTERFEROMETRY Introduction Michelson radio interferometer Michelson stellar interferometer Intensity interferometer Reflection interferometers Exercises 2.6 SPECKLE INTERFEROMETRY 2.7 OCCULTATIONS Background Techniques Analysis 2.8 RADAR Introduction Theoretical principles Equipment Data analysis Meteors Exercise 2.9 ELECTRONIC IMAGES Image formats Image compression Image processing Grey scaling Image combination Spatial filtering Photometry 3.1 PHOTOMETRY Background Magnitudes 192 192 193 193 196 196 197 198 199 199 199 200 201 204 204 205 223 227 232 233 233 237 237 241 244 245 245 245 251 252 254 255 255 255 256 257 257 258 259
CONTENTS xi Filter systems 262 Stellar parameters 266 Exercises 281 3.2 PHOTOMETERS 281 Instruments 281 Visual photometers 282 Photographic photometry 282 Photoelectric photometers 286 Observing techniques 294 Data reduction and analysis 297 Exercise 300 Spectroscopy 301 4.1 SPECTROSCOPY 301 Optics 301 Prisms 301 Diffraction gratings 312 Interferometers 320 Fabry-Perot interferometer 320 Michelson interferometer 327 Holography 333 Exercises 334 4.2 SPECTROSCOPES 334 Basic design considerations 334 Prism-based spectroscopes 341 Grating spectroscopes 345 Techniques of spectroscopy 348 Future developments 355 Exercises 355 Other Techniques 356 5.1 ASTROMETRY 356 Background 356 Coordinate systems 356 Position angle and separation 358 Micrometers 359 Photography 364 Electronic images 366 Measurement and reduction 366 Exercises 368 5.2 POLARIMETRY 368 Background 368 Stokes' parameters 369
xii CONTENTS Optical components for polarimetry 372 Birefringence 372 Polarisers ^ 375 Converters 379 Depolarises 383 Polarimeters 383 Photographic polarimeters 384 Photoelectric polarimeters 385 Data reduction and analysis 388 Exercises 390 5.3 SOLAR STUDIES 390 Introduction 390 Solar telescopes 391 Spectrohelioscope 394 Narrow band filters 395 Coronagraph 401 Solar oscillations 403 Other solar observing methods 404 Exercise 405 5.4 MAGNETOMETRY 405 Background 405 Zeemah effect 405 Magnetometers 412 Data reduction and analysis 416 Appendices 417 I Magnitudes and spectral types of bright stars 417 II North polar sequence 420 III Standard stars for the UBV photometric system 423 IV Standard stars for the uvby photometric system 426 V Standard stars for MK spectral types 435 VI Standard stars for polarimetry 443 VII Julian date 445 VIII Catalogues 447 IX Answers to the exercises 449 Bibliography 451 Index 458