1. Historical introduction ...................................... 1
1.1. Period 1608-1672 ........................................ 1
1.2. Period 1672-1840 ....................................... 11
1.3. William Herschel's telescopes .......................... 15
2. Basic (Gaussian) optical theory of telescopes ............... 21
2.1. Basic function of a telescope .......................... 21
2.2. The ideal optical system, geometrical optics and
Gaussian optics ........................................ 23
2.2.1. The ideal optical system and Gaussian concept ... 23
2.2.2. Geometrical optics and geometrical wavefronts ... 26
2.2.3. The Gaussian optics approximation ............... 27
2.2.4. The conventional telescope with an ocular ....... 36
2.2.5. Basic forms of reflecting telescope ............. 40
2.2.6. The scale of astronomical telescopes and the
magnification in afocal use of compound
telescopes ...................................... 54
2.2.7. "Wide-field" telescopes and multi-element
forms ........................................... 55
3. Aberration theory of telescopes ............................. 57
3.1. Definition of the third order approximation ............ 57
3.2. Characteristic Function and Seidel (3rd order)
aberrations: aberration theory of basic telescope
forms .................................................. 59
3.2.1. The Characteristic Function of Hamilton ......... 59
3.2.2. The Seidel approximation: third order
aberration coefficients ......................... 63
3.2.3. Seidel coefficients of some basic reflecting
telescope systems ............................... 65
3.2.4. Analytical (third order) theory for 1-mirror
and 2-mirror telescopes ......................... 69
3.2.5. Higher order aberrations and system
evaluation ...................................... 82
3.2.6. Analytical expressions for a 1-mirror
telescope and various forms of 2-mirror
telescopes (Classical, Ritchey-Chretien,
Dall-Kirkham, Spherical Primary) ................ 88
3.2.7. Other forms of aplanatic 2-mirror telescopes
(Schwarzschild, Couder) ........................ 111
3.2.8. Scaling laws from normalized systems to real
apertures and focal lengths .................... 126
3.3. Nature of third order aberrations and conversion
formulae from wavefront aberration to other forms ..... 128
3.3.1. Spherical aberration (SI) ...................... 128
3.3.2. Coma (SII) ...................................... 131
3.3.3. Astigmatism (SIII) and field curvature (SIV) .... 135
3.3.4. Distortion (SV) ................................ 138
3.3.5. Examples of conversions ........................ 139
3.3.6. Conversions for Gaussian aberrations ........... 139
3.4. The theory of aspheric plates ......................... 140
3.5. The role of refracting elements in modern
telescopes: chromatic variations of first order and
third order aberrations ............................... 146
3.6. Wide-field telescopes ................................. 148
3.6.1. The symmetrical stop position: the Bouwers
telescope ...................................... 148
3.6.2. The Schmidt telescope .......................... 151
3.6.3. The Maksutov telescope ......................... 165
3.6.4. More complex variants of telescopes derived
from the principles of the Schmidt, Bouwers
and Maksutov systems ........................... 174
3.6.5. Three- or multi-mirror telescopes (centered) ... 223
3.7. Off-axis (Schiefspiegler) and decentered telescopes ... 255
3.7.1. Two- and three-mirror Schiefspiegler ........... 255
3.7.2. The significance of Schiefspiegler theory in
the centering of normal telescopes: formulae
for the effects of decentering of 2-mirror
telescopes ..................................... 261
3.8. Despace effects in 2-mirror telescopes ................ 279
3.8.1.Axial despace effects ........................... 279
3.8.2.Transverse despace effects ...................... 287
3.9. Zernike polynomials ................................... 288
3.10.Diffraction theory and its relation to aberrations .... 293
3.10.1.The Point Spread Function (PSF) due to
diffraction at a rectangular aperture .......... 293
3.10.2.Coherence ...................................... 297
3.10.3.The Point Spread Function (PSF) due to
diffraction at a circular aperture ............. 298
3.10.4.The Point Spread Function (PSF) due to
diffraction at an annular aperture ............. 302
3.10.5.The diffraction PSF in the presence
of small aberrations ........................... 304
3.10.6.The diffraction PSF in the presence of small
aberrations and an annular aperture ............ 310
3.10.7.The diffraction PSF in the presence of
larger aberrations: the Optical Transfer
Function (OTF) ................................. 312
3.10.8.Diffraction effects at obstructions in
the pupil other than axial central
obstruction .................................... 322
4. Field correctors and focal reducers or extenders ........... 325
4.1. Introduction .......................................... 325
4.2. Aspheric plate correctors ............................. 327
4.2.1. Prime focus (PF) correctors using aspheric
plates ......................................... 327
4.2.2. Cassegrain or Gregory focus correctors
using aspheric plates .......................... 340
4.3. Correctors using lenses ............................... 348
4.3.1. Prime focus (PF) correctors using lenses ....... 348
4.3.2. Secondary focus correctors using lenses ........ 372
4.4. Atmospheric Dispersion Correctors (ADC) ............... 392
4.5. Focal reducers and extenders .......................... 404
4.5.1. Simple reducers and extenders in front of
the image ...................................... 404
4.5.2. Wide-field focal reducers (FR) as
a substitute for a prime focus ................. 406
4.5.3. Other Cassegrain focal reducers ................ 414
5. Major telescopes from Lord Rosse to about 1980 ............. 419
5.1. Major telescopes in the speculum mirror epoch to
1865 .................................................. 419
5.2. Glass optics telescopes up to the Palomar 200-inch .... 431
5.3. Reflectors after the 200-inch Palomar Telescope
up to about 1980 ...................................... 449
Appendices .................................................... 465
A. List of mathematical symbols ............................ 467
B. Portrait gallery ........................................ 487
References .................................................... 502
List of Figures ............................................... 513
List of Tables ................................................ 527
Name Index .................................................... 531
Subject Index ................................................. 536
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