Astronomical Optics Second Edition DANIEL J. SCHROEDER Professor of Physics and Astronomy, Emeritus Department of Physics and Astronomy Beloit College, Beloit, Wisconsin ACADEMIC PRESS A Harcourt Science end Technology Company San Diego San Franciso New York Boston London Sydney Tokyo
Contents Preface Chapter 1 Introduction 1.1. A Bit of History 1 1.2. Approach to Subject 4 1.3. Outline of Book 4 Chapter 2 Preliminaries: Definitions and Paraxial Optics 7 2.1. Sign Conventions 8 2.2. Paraxial Equation for Refraction 9 2.3. Paraxial Equation for Reflection 12 2.4. Two-Surface Refracting Elements 14 2.5. Two-Mirror Telescopes 17 2.6. Stops and Pupils 22 2.7. Concluding Remarks 25 Bibliography 26 Chapter 3 Fermat's Principle: An Introduction 27 3.1. Fermat's Principle in General 28 3.2. Fermat's Principle and Refracting Surfaces 31 3.3. Wave Interpretation of Fermat's Principle 36 3.4. Fermat's Principle and Reflecting Surfaces 37 3.5. Conic Sections 41 3.6. Fermat's Principle and the Atmosphere 42
Vlll Contents 3.7. Concluding Remarks 45 References 47 Bibliography 47 Chapter 4 Introduction to Aberrations 48 4.1. Reflecting Conies and Focal Length 49 4.2. Spherical Aberration 50 4.3. Reflecting Conies and Finite Object Distance 57 4.4. Off-Axis Aberrations 59 4.5. Aberration Compensation 61 References 69 Bibliography 69 Chapter 5 Fermat's Principle and Aberrations 70 5.1. Application to Surface of Revolution 70 5.2. Evaluation of Aberration Coefficients 75 5.3. Ray and Wavefront Aberrations 78 5.4. Summary of Aberration Results, Stop at Surface 84 5.5. Aberrations for Displaced Stop 88 5.6. Aberrations for Multisurface Systems 93 5.7. Curvature of Field 97 5.8. Aberrations for Decentered Pupil 103 5.9. Concluding Remarks 109 Appendix A: Comparison with Seidel Theory 110 References 111 Bibliography 111 Chapter 6 Reflecting Telescopes 112 6.1. Paraboloid 113 6.2. Two-Mirror Telescopes 115 6.3. Alignment Errors in Two-Mirror Telescopes 132 6.4. Three-Mirror Telescopes 144 6.5. Four-Mirror Telescopes 154 6.6. Concluding Remarks 161 References 162 Bibliography 162 Chapter 7 Schmidt Telescopes and Cameras 164 7.1. General Schmidt Configuration 165 7.2. Characteristics of Aspheric Plate 167 7.3. Schmidt Telescope Example 174 7.4. Achromatic Schmidt Telescope 177
Contents IX 7.5. Solid- and Semisolid-Schmidt Cameras 181 References 184 Bibliography 184 Chapter 8 Catadioptric Telescopes and Cameras 185 8.1. Schmidt-Cassegrain Telescopes 185 8.2. Cameras with Meniscus Correctors 197 8.3. All-Reflecting Wide-Field Systems 204 References 205 Chapter 9 Auxiliary Optics for Telescopes 206 9.1. Field Lenses, Flatteners 207 9.2. Prime Focus Correctors 210 9.3. Cassegrain Focus Correctors 216 9.4. Cassegrain Focal Reducers 220 9.5. Atmospheric Dispersion Correctors 225 9.6. Fiber Optics 237 References 239 Bibliography 239 Chapter 10 Diffraction Theory and Aberrations 240 10.1. Huygens-Fresnel Principle 241 10.2. Perfect Image: Circular Aperture 246 10.3. The Near Perfect Image 257 10.4. Comparison: Geometric Aberrations and the Diffraction Limit 270 10.5. Diffraction Integrals and Fourier Theory 271 References 275 Bibliography 275 Chapter 11 Transfer Functions; Hubble Space Telescope 277 11.1. Transfer Functions and Image Characteristics 277 11.2. Hubble Space Telescope, Prelaunch Expectations 291 11.3. Hubble Space Telescope, Postlaunch Reality 298 11.4. Concluding Remarks 302 References 303 Bibliography 303 Chapter 12 Spectrometry: Definitions and Basic Principles 304 12.1. Introduction and Definitions 305 12.2. Slit Spectrometers 308
X Contents 12.3. Fiber-Fed Spectrometers 317 12.4. Slitless Spectrometers 318 12.5. Spectrometers in Diffraction Limit 318 References 320 Bibliography 320 Chapter 13 Dispersing Elements and Systems 321 13.1. Dispersing Prism 321 13.2. Diffraction Grating; Basic Relations 323 13.3. Echelles 327 13.4. Grating Efficiency 331 13.5. Fabry-Perot Interferometer 342 13.6. Fourier Transform Spectrometer 347 13.7. Concluding Remarks 350 References 350 Bibliography 350 Chapter 14 Grating Aberrations; Concave Grating Spectrometers 352 14.1. Application of Fermat's Principle to Grating Surface 353 14.2. Grating Aberrations 357 14.3. Concave Grating Mountings 362 References 367 Bibliography 367 Chapter 15 Plane Grating Spectrometers 368 15.1. All-Reflecting Spectrometers 369 15.2. Pixel Matching 377 15.3. Fast Spectrometers 378 15.4. Fiber-Fed Spectrometers 383 15.5. Echelle Spectrometers 384 15.6. Nonobjective Slitless Spectrometers 396 15.7. Concluding Remarks 407 References 407 Bibliography 407 Chapter 16 Adaptive Optics: An Introduction 409 16.1. Effects of Atmospheric Turbulence 410 16.2. Correction of Wavefront Distortion 415 16.3. Adaptive Optics: Systems and Components 421 16.4. Concluding Remarks 423 References 424 Bibliography 424
Contents XI Chapter 17 Detectors, Signal-to-Noise, and Detection Limits 425 17.1. Detector Characteristics 426 17.2. Signal-to-Noise Ratio 433 17.3. Detection Limits and Signal-to-Noise Ratio 435 17.4. Detection Limits: Stellar Photometry 438 17.5. Detection Limits: Spectroscopy 440 References 443 Bibliography 443 Chapter 18 Large Mirrors and Telescope Arrays 444 18.1. Large Mirrors 444 18.2. Telescope Arrays; Interferometers 451 References 457 Bibliography 457 Table of Symbols 459 Index 467