THE DESIGN AND CONSTRUCTION OF LARGE OPTICAL TELESCOPES
CONTENTS INTRODUCTION 1 1 ASTRONOMICAL OBSERVATIONS 5 1 1 ROLE OF ASTRONOMICAL TELESCOPES 5 1 2 SOURCE CHARACTERISTICS 5 1 2 1 INTENSITY 5 1 2 2 DISTRIBUTION OF SOURCES OF INTEREST IN THE SKY 7 1 3 OBSERVING THROUGH THE ATMOSPHERE 9 1 3 1 ATMOSPHERIC EXTINCTION 9 1 3 2 ATMOSPHERIC EMISSION 11 1 3 3 ATMOSPHERIC REFRACTION 12 1 3 4 ATMOSPHERIC TURBULENCE BASIC NOTIONS 13 1 3 5 ATMOSPHERIC TURBULENCE THE PHYSICS OF SEEING 17 1 4 BACKGROUND SOURCES 19 1 4 1 CELESTIAL BACKGROUNDS 19 1 4 2 ATMOSPHERIC BACKGROUND 22 1 4 3 STRAY LIGHT AND DETECTOR BACKGROUND 22 1 4 4 COPING WITH ATMOSPHERIC AND TELESCOPE THERMAL EMISSION 22 1 5 SIGNAL TO NOISE RATIO 24 1 6 TIME 28 1 6 1 SIDEREAL TIME 28 1 6 2 JULIAN DATE 28 1 7 COORDINATE SYSTEMS 29 1 8 POINTING CORRECTIONS 31 1 8 1 PRECESSION AND NUTATION 32 1 8 2 PROPER MOTION 32 1 8 3 PARALLAX 32 1 8 4 ABERRATION OF STARLIGHT 33 1 8 5 ATMOSPHERIC REFRACTION 35 1 9 TELESCOPE POINTING AND TRACKING PROCEDURE 35 1 9 1 TARGET ACQUISITION 35 1 9 2 GUIDING 36 1 9 3 GUIDE STAR CATALOGS 36 1 10 TELESCOPES AND INTERFEROMETERS 37 REFERENCES 39 BIBLIOGRAPHY 40 2 INSTRUMENTS 41 2 1 MAIN TYPES OF INSTRUMENT 41 2 1 1 CAMERAS 42 2 1 2 PHOTOMETER 43 2 1 3 POLARIMETERS 44 2 1 4 DISPERSING SPECTROMETERS 44 2 1 5 FABRY PEROT SPECTROMETER 47 2 1 6 FOURIER TRANSFORM SPECTROMETER 48 2 2 OPTICAL THROUGH MID INFRARED DETECTORS 49 2 2 1 PHOTON DETECTION IN SEMICONDUCTORS 50 2 2 2 CCD DETECTORS 52 2 2 3 INFRARED ARRAY DETECTORS 53 2 2 4 SPECI C DETECTOR CHARACTERISTICS 55 2 3 RELAY OPTICS 59 2 4 CRYOGENIC SYSTEMS 60 REFERENCES 61 BIBLIOGRAPHY 61 3 DESIGN METHODS AND PROJECT MANAGEMENT 62 3 1 THE PROJECT LIFE CYCLE 63 3 2 THE TOOLS OF SYSTEMS ENGINEERING 66 3 2 1 DESIGN REFERENCE PROGRAM 67 3 2 2 REQUIREMENTS OWDOWN 69 3 2 3 ERROR BUDGETS 72 3 2 4 END TO END COMPUTER SIMULATIONS 74 3 2 5 DESIGN TESTABILITY AND FORGIVENESS 75 3 2 6 SCALING LAWS 76 3 2 7 COST MODELS 78 3 2 8 COST AS A DESIGN VARIABLE 79 3 2 9 OBSERVATORY PERFORMANCE METRICS 81 3 3 PROJECT MANAGEMENT 86 3 3 1 GENERAL PRINCIPLES 87 3 3 2 PROJECT ORGANIZATION 88 3 3 3 WORK BREAKDOWN STRUCTURE 89 3 3 4 PROJECT DATA BASE 90 3 3 5 PROCUREMENT STRATEGY 90 3 3 6 TECHNOLOGY DEVELOPMENT 91 3 3 7 RELIABILITY 93 3 3 8 QUALITY ASSURANCE VERI CATION AND VALIDATION 94 3 3 9 INTERFACE DOCUMENTS 95 3 3 10 CON GURATION MANAGEMENT 95 3 4 PROJECT SCHEDULING 96 3 5 RISK ANALYSIS 99 3 6 COST ESTIMATES AND BUDGETING 100 3 6 1 APPROACHES TO COST ESTIMATING 100 3 6 2 BUDGETS OF MAIN FUNDING AGENCIES 101 3 6 3 COST ESTIMATE ACCURACY 101 3 6 4 CONSTRUCTION OF MULTIPLE UNITS 102 3 6 5 BUDGETING AND RESOURCE PLANNING 103 REFERENCES 104 BIBLIOGRAPHY 105 4 TELESCOPE OPTICS 106 4 1 OPTICAL DESIGN FUNDAMENTALS 106 4 1 1 FUNDAMENTAL PRINCIPLES 106 4 1 2 EQUATIONS OF CONIC SURFACES 108 4 1 3 STOPS AND PUPILS 108 4 1 4 PRIMARY ABERRATIONS 110 4 1 5 WAVEFRONT ERRORS 111 4 1 6 DI RACTION E ECTS 114 4 1 7 IMAGE FORMATION 115 4 2 TELESCOPE OPTICAL CON GURATIONS 121 4 2 1 SINGLE MIRROR SYSTEMS 121 4 2 2 TWO MIRROR SYSTEMS 122 4 2 3 THREE AND FOUR MIRROR SYSTEMS 124 4 2 4 SYSTEMS WITH SPHERICAL MIRRORS 126 4 2 5 AUXILIARY OPTICS 126 4 3 OPTICAL ERROR BUDGET 127 4 4 CRITERIA FOR IMAGE QUALITY 129 4 5 SYSTEM ISSUES 134 4 5 1 FOCUS SELECTION 134 4 5 2 SELECTION OF F RATIO 136 4 5 3 MATCHING PLATE SCALE TO THE DETECTOR RESOLUTION 137 4 6 MIRROR BLANK MATERIALS 139 4 6 1 GENERALITIES 139 4 6 2 BOROSILICATE GLASS 142 4 6 3 ULE FUSED SILICA 143 4 6 4 LOW THERMAL EXPANSION GLASS CERAMIC 143 4 6 5 SILICON CARBIDE 144 4 6 6 BERYLLIUM 145 4 6 7 ALUMINUM 146 4 7 MIRROR STRUCTURAL DESIGN 146 4 7 1 LIGHTWEIGHTED MIRRORS 150 4 7 2 SEGMENTED MIRROR SYSTEMS 151 4 7 3 THERMAL E ECTS 155 4 8 MIRROR PRODUCTION 157 4 8 1 COMPUTER CONTROLLED LAPPING 160 4 8 2 STRESSED MIRROR GURING 161 4 8 3 ACTIVE LAP GURING 162 4 8 4 ULTRAPRECISION MACHINING 162 4 8 5 ION BEAM GURING 163 4 8 6 POST GURING MECHANICAL DEFORMING 164 4 9 OPTICAL SURFACE TESTING DURING MANUFACTURE 165 4 9 1 TESTING PHILOSOPHY 165 4 9 2 MAIN TESTING TECHNIQUES 167 4 9 3 TESTING THE GURE OF PRIMARY MIRRORS 171 4 9 4 TESTING SECONDARY MIRRORS 172 4 9 5 MEASURING THE RADIUS OF CURVATURE 173 4 9 6 ELIMINATING THE E ECT OF GRAVITY 173 4 9 7 TESTING CRYOGENIC MIRRORS 173 4 10 MIRROR COATINGS AND WASHING 174 4 10 1 MIRROR CLEANING 174 4 10 2 COATING PLANT 176 REFERENCES 177 BIBLIOGRAPHY 181 5 STRAY LIGHT CONTROL 183 5 1 CAUSES OF STRAY LIGHT 183 5 2 FINDING AND XING STRAY LIGHT PROBLEMS 184 5 3 BA ES AND STOPS 185 5 3 1 APERTURE STOP 185 5 3 2 FIELD STOP 186 5 3 3 LYOT STOP 186 5 3 4 BA ES 187 5 3 5 BA ES FOR CASSEGRAIN SYSTEMS 187 5 4 SCATTERING PROCESSES 188 5 5 STRAY LIGHT ANALYSIS 189 5 6 SURFACE SCATTERING PROPERTIES 193 5 6 1 SCATTER FROM MIRRORS 193 5 6 2 SCATTER FROM DI USE BLACK SURFACES 195 5 7 AN EXAMPLE OF PROTECTION AGAINST O AXIS SOURCES HST 197 5 8 AN EXAMPLE OF MINIMIZING STRAY LIGHT FROM SELF EMISSION NGST 198 5 9 MINIMIZING THERMAL BACKGROUND IN GROUND BASED TELESCOPES 199 REFERENCES 200 BIBLIOGRAPHY 201 6 TELESCOPE STRUCTURE AND MECHANISMS 202 6 1 GENERAL PRINCIPLES 203 6 1 1 KINEMATIC MOUNTING 203 6 1 2 MINIMIZING DECOLLIMATION 205 6 1 3 USE OF PRELOAD 207 6 1 4 LOAD PATHS 208 6 1 5 DESIGNING OUT STICK SLIP AND MICROLURCHES 208 6 1 6 CHOICE OF MATERIALS 210 6 1 7 ATHERMALIZATION 212 6 1 8 STRUCTURAL DESIGN 213 6 2 DESIGN REQUIREMENTS 214 6 2 1 OPERATIONAL REQUIREMENTS 214 6 2 2 SURVIVAL CONDITIONS 215 6 3 MIRROR MOUNTS 219 6 3 1 MOUNTS FOR SINGLE MIRRORS 219 6 3 2 MOUNTS FOR SEGMENTED MIRROR SYSTEMS 223 6 4 TELESCOPE TUBE 224 6 4 1 TUBE TRUSS 225 6 4 2 TRIPOD AND TOWER TYPE SUPPORTS FOR SECONDARY MIRRORS 228 6 4 3 THERMAL E ECTS 229 6 4 4 CASSEGRAIN MIRROR SPIDER 230 6 4 5 PRIMARY MIRROR CELL 233 6 5 MOUNTS FOR GROUND BASED TELESCOPES 233 6 5 1 EQUATORIAL MOUNT 233 6 5 2 ALTITUDE AZIMUTH MOUNT 235 6 5 3 ALTITUDE ALTITUDE MOUNT 236 6 5 4 FIXED ALTITUDE AND XED PRIMARY MIRROR MOUNTS 236 6 6 BEARINGS FOR GROUND TELESCOPES 237 6 6 1 ROLLING BEARINGS 238 6 6 2 HYDROSTATIC BEARINGS 238 6 7 MISCELLANEOUS MECHANISMS 242 6 7 1 OVERALL TELESCOPE ALIGNMENT 242 6 7 2 OPTICS ALIGNMENT AND FOCUSING DEVICES 242 6 7 3 ACTIVE SECONDARY MIRROR FOR INFRARED CHOPPING AND ELD STABILIZATION 243