INDEX
- A
- Abbé, roof prism, 162
- Aberration, compensated by minute change of focus, 266
- illuminates the diffraction minima, 265
- relation determines of focus and aperture, 266
- Achromatic long relief ocular, 146
- objective, 77
- Achromatism, condition for, 78
- determination of, 78
- imperfection of, 87
- Adjustment where Polaris invisible, 235
- Air waves, length of, 255
- Alt-azimuth mount for reflector, 102
- mounts, with slow motions, 102
- setting up an, 228
- Anastigmats, 84
- Annealing, pattern of strain, 68
- Astigmatism, 84, 209
- of figure, 210
- Astronomy, dawn of popular, 19
- B
- Bacon, Roger, alleged description of telescopes, 6
- Barlow lens, 152
- “Bent,” objective, 86
- Binocular, 2
- advantage of, exaggerated, 151
- for strictly astronomical use, 152
- telescopes for astronomical use, 163
- C
- Camouflage, in optical patents, 97
- Cassegrain, design for reflecting telescope, 22
- Cassegrain, sculptor and founder of statues, 22
- Cell, taking off from a telescope, 202
- Chromatic aberration, 11, 76
- investigation of, 210
- correction, differences in, 91
- error of the eye, 90
- Clairault’s condition, 81
- two cemented forms for, 81
- Clarks, portable equatorial mounting, 109
- terrestrial prismatic eyepiece, 158
- Clock, the cosmic, 233
- Clock drive, 110, 174
- Clock mechanism, regulating rate of motor, 179
- Coddington lens, 137
- Cœlostat constructions, 126
- tower telescopes, 127
- Color correction, commonly used, 211
- examined by spectroscope, 211
- of the great makers, 90
- Coma-free, condition combined with Clairault’s, 83
- Comet seeker, Caroline Herschel’s 118
- seekers with triple objective, 119
- Crowns distinguished from flints, 64
- Curves, struggle for non-spherical, 18
- D
- Davon micro-telescope, 148
- Dawes’ Limit, 261
- in physiological factors, 263
- Declination circle, 108
- adjustment of, 239
- Declination circle, adjustment by, 237
- facilitates setting up instrument, 110
- Definition condition for excellence of, 254
- good in situations widely different, 254
- DeRheita, 12
- constructed binoculars, 13
- terrestrial ocular, 13
- Descartes’ dioptrics, publication of, 11
- lens with elliptical curvature, 12
- Dew cap, 219
- Diaphragms, importance of, 43
- Diffraction figure for bright line, 269
- pattern, 256
- solid, apparent diameter of, 262
- solid of planet, 269
- solid for a star, 260
- spectra, 190
- system, scale of, 260
- varies inversely with aperture, 260
- through objective, 258
- Digges, account suggests camera obscura, 7
- Dimensions, customary, telescope of, 24
- Discs, inspection of glass, 66
- roughing to form, 69
- Distortion, 86
- Dolland, John, 28
- published his discovery of achromatism, 29
- Peter, early triple objective, 29
- Dome wholly of galvanized iron, 250
- Domes, 246
- Driving clock, a simple, 174
- pendulum controlled, 177
- clocks spring operated, 175
- E
- English equatorial, 110
- mounts, mechanical stability of, 113
- Equatorial, adjustments of, 230
- Equatorial, coudé, 124
- mount, different situations in using, 229
- mount, first by Short, 104
- mount, pier overhung, 115
- mount in section, 107
- two motions necessary in, 106
- Equilibrating levers, devised by T. Grubb, 39
- Evershed, direct vision solar spectroscope, 189
- Eye lens, simple, preferred by Sir W. Herschel, 136
- Eyepiece, compensating, 142
- Huygenian, 139
- Huygenian, achromatism of, 140
- Huygenian, with cross wires, 140
- Huygenian, field of, 141
- Huygenian focal length of, 143
- measuring focus of, 136
- microscope form, 147, 148
- monocentric, 139
- a simple microscope, 134
- Tolles solid, 141
- F
- Field, curvature of, 85
- glass, arrangement of parts, 151
- Galilean, 150
- lens diameter possible, 150
- Field lens, 139
- Figuring locally, 73
- process of, 73
- Filar micrometer, 172
- Finder, 108, 132
- adjustment of, 230
- Fine grinding, 69
- Fixed eyepiece mounts, 118
- Flints, highly refractive due to Guinand, 36
- Foucault, 39
- development of silver on glass reflector, 41
- knife edge test, 212
- Foucault, methods of working and testing, 41
- Fraunhofer, 36
- applied condition of absence of coma, 82
- form of objectives, 37
- long list of notable achievements, 38
- “Front view” telescope, 32
- mechanical difficulty of, 33
- Furnaces, glass, classes of, 59
- G
- Galilean telescope, small field of, 9
- Galileo, exhibited telescope to senators of Venice, 8
- grasps the general principles, 7
- produces instrument magnifying 32 times, 8
- Gascoigne, William, first using genuine micrometer, 12
- Gauss, Objective, 82
- Gerrish, application of drive, 181
- motor drive, 179
- Ghosts, 137
- Glass, dark, as sunshade, 166
- forming and annealing, 62
- inspection of raw, 61
- losses by volatilization, 58
- materials of, 59
- origin of, 57
- persistent bubbles in, 58
- a solid solution, 57
- Grating spectroscopes, 190
- Gratings, spectroscope, 189
- Gregory, James, described construction which bears his name, 19
- failed of material success, 20
- Grubb, Sir Howard, objectives, 74
- Guinand, Pierre Louis, improvements in optical glass, 36
- H
- Hadley, disclosed test for true figure, 27
- John, real inventor of reflector, 25
- Hadley’s reflector, tested with satisfactory results, 26
- Hall, Chester Moor, designed first achromatic telescope, 27
- had telescopes made as early as 1733, 27
- Hand telescope, magnifying power, 150
- monocular, 151
- Hartmann test, 213
- on large objectives, 267
- principle of, 214
- Hartness, turret telescope, 130, 131
- Heliometer, principle of, 171
- Hensoldt, prism form, 163
- Herschel’s discovery of Uranus, 32
- forty foot telescope, 34
- Sir John, 35
- Sir John, proposed defining condition, 81
- Sir William, 31
- Herschel’s time, instruments of, 35
- Hevelius, construction for objective of 150 feet, 17
- directions for designing Galilean and Keplerian telescopes, 14
- invention of first periscope, 15
- Johannes, 13
- mention of advantage of plano convex lens, 14
- mentions telescope due to DeRheita, 14
- Housing reflector of 36 inch aperture, 243
- rolling on track, 242
- simplest instrument for fixed, 241
- Huygens, Christian, devised methods of grinding & polishing, 16
- Huygens’ eyepiece, introduction of, 24
- Huygens, sketch of Mars, 16
- I
- Image, correct extra focal, 208
- critical examination of, 204
- Image, curvature of, 87
- seen without eyepiece, 134
- showing unsymmetrical coloring, 208
- Interference rings, eccentric, 205
- Irradiation, 262
- J
- Jansen, Zacharius, 4
- K
- Kellner, ocular, 145
- Kepler, astronomical telescope, 10
- differences of from Galilean form, 10
- Knife edge test of parabolic mirror, 212
- L
- Lacquer, endurance of coating, 223
- Latitude scale, 232
- Lenses, determinate forms for, 80
- Lens, magnifying power of, 134
- “crossed,” 24
- polishing the fine ground, 70
- power of, 78
- triple cemented, a useful ocular, 138
- simple achromatic, 137
- single, has small field, 137
- spotted, cleaning of, 217
- Light grasp and resolving power, 265
- small telescope fails in, 264
- Light ratio of star magnitudes, 264
- Light transmitted by glass, 53
- Lippershey, Jan, 2
- discovery, when made, 5
- retainer to, 3
- Lunette à Napoleon Troisiéme, 154, 155, 162
- M
- Magnifying power, directly as ratio of increase in tangent, 135
- powers, increase of, 273
- Marius, Simon, 5
- used with glasses from spectacles, 5
- Marius, picked up satellites of Jupiter, 5
- Meridian photometer, 194
- Metius, James, 4
- Metius, tale of, 4
- Micrometer, double image, 171
- square bar, 171
- Micrometers, 168
- Micrometry, foundations of, 12
- Mirror’s, aberrations of, 92
- adjustment of, 206
- concave spherical, 92
- final burnishing of, 226
- hyperboloidal, 96
- lacquer coating for surface, 221
- mounting, by Browning, 49
- parabolic oblique, shows aberration, 95
- surface, prevention of injury to, 220
- Mittenzwey ocular, 141
- Mountain stations, good or very bad, 254
- Mounts, alt-azimuth and equatorial, 98
- Myopia, glasses for, came slowly, 2
- N
- Navicula Lyra, stages of resolution of, 271
- Newton, abandoned parabolic mirror, 21
- blunder in experiment, 20
- gave little information about material for mirrors, 23
- Isaac, attempt at a reflector, 20
- Normal spectra, 190
- O
- Objective, adjustable mount for, 44
- adjusting screws of, 44
- Clark’s form, 83
- cleansing, 203
- examination of, 202
- Objective, four-part, 85
- Fraunhofer flint-ahead, 83
- how to clean, 216
- spacers, to take out, 217
- typical striæ in, 203
- Objective prism, photographing with, 185, 187
- Objectives, crown glass equiconvex, 80
- over-achromatized, 90
- rated on focal length for green 24
- Observatories, cost of Romsey, 252
- Observatory at small expense, 249
- Romsey, description of, 249
- with simple sliding roof, 245
- Observing box, 229
- Oblique fork alt-azimuth, 100
- Ocular, apparent angular field of, 146
- terrestrial, 147
- Tolles terrestrial, 147
- typical form, 45
- Oculars, radius of curvature of image in, 146
- undesirability of short focus, 275
- Open fork mount, 115
- well suited to big reflectors, 117
- Optical axis, to adjust declination of, 238
- Optical glass, classes of, 63
- data and analysis of, 64
- industry, due to single man, 36
- production of, 60
- Orthoscopic ocular, 145
- P
- Parallactic mount, 104
- Petition for annulment of Dolland’s patent, 29
- Photometer, artificial star Zöllner, 194
- extinction, 198
- photoelectric cell, 199
- precision of astronomical, 199
- selenium cell, 199
- Zöllner, 197
- Photometers, three classes in stellar, 193
- “Photo-visual, objective,” 89
- Pillar-and-claw stand, 98
- Pillar mount, 240
- Pitch, optician’s, 71
- Placement for tripod legs, 236
- Polar and coudé forms of reflector, 125
- axis, adjustment of by level, 232
- axis, alignment to meridian, 232
- axis, setting with finder altitude of, 234
- telescope, 119, 122
- Polaris, hour angle of, 233
- a variable star, 199
- Polarizing photometer, 193
- Pole, position, 234
- Polishing machine, 70
- surface of tool, 72
- tool, 71
- Porro’s second form, 157
- work, original description of, 156
- Porta, description unintelligible, 7
- Portable equatorial, adjustment of, 230
- telescopes, mounting of, 228
- Porter polar reflector, 130
- Position angle micrometer of Lowell Observatory, 173
- Powers, lowest practicable, 276
- Prismatic inversion, Porro’s first form, 155
- Prismatic inverting system, the first, 154
- Prisms, Dove’s, 154
- Prism field glasses, stereoscopic effect of, 159
- Prism glass, 152
- loss of light in, 160
- objectives of, 161
- weak points of, 160
- R
- Resolving constant, magnification to develop, 275
- power and verity of detail, 2
- power of the eye, 274
- Reticulated micrometer, 169
- Reversion prism, 153
- Right ascension circle, 108
- Ring micrometer, 169
- computation of results of, 170
- Ring system faults due to strain, 205
- “Romsey” observatory type, 248
- Rack motion in altitude, 100
- Ramsden, ocular, 144
- Reflection, coefficient of, from silvered surface, 54
- Reflector costs, 55
- cover for, 242
- development in England, 41
- for astrophysical work, 56
- light-grasp of, 53
- relative aperture of, 50
- section of Newtonian, 45
- skeleton construction, 49
- suffers from scattered light, 56
- working field of, 55
- Refractive index, 63
- Refractors and reflectors, relative advantages of, 52
- few made after advent of reflector, 27
- in section, 43
- light transmission of, 53
- Refractors, relative equivalent apertures of, 54
- tubes of, 42
- S
- Scheiner, Christopher, use of Kepler’s telescope, 11
- devised parallactic mount, 11
- Secondary spectrum, 87
- new glasses reducing, 88
- Seeing, 257
- conditions, for difference of aperture, 257
- conditions generally bad, 253
- standard scale of, 256
- true inwardness of bad, 253
- Separating power, to compute, 261
- Short, James, mastered art of figuring paraboloid, 27
- took up Gregorian construction with success, 27
- Shortened telescope, 152
- Sights, on portable mount, 229
- Silver films, condition of, 54
- Silvering, Ludin’s process, 225
- processes, 222
- process, Dr. Brashear’s, 222
- Sine condition, Abbé’s, 82
- Slit, spectroscope, Abbé type, 184
- Snow cœlostat telescope, 127
- Solar diagonal, 166
- eye piece diaphragms in, 168
- early spectroscopes, 188
- polarizing eyepiece, 167
- spectroscope, 187
- Spacers, 44, 218
- Spectacle lenses, combination of, 2
- Spectacles for presbyopia, 2
- invention of, 1
- Spectra, visibility of stellar, 183
- Spectro-heliograph, principle of, 191
- simple type of Hale’s, 191
- Spectroscope, 182
- construction of astronomical, 182
- of Lowell refractor, 185
- ocular, McClean form, 183
- Specula, small, methods of support, 49
- Speculum metal composition of, 24
- Sphenoid prisms, 158, 163
- Spherical aberration, 11
- amount of, 80
- annulling in both directions, 84
- examination for, 207
- quick test of, 267
- remedy for, 79
- concave mirror, errors of, 22
- Star, appearance of, 204
- artificial, 66, 203
- diagonal, 165
- disc, apparent diameter of, 259
- image of reflector, 206
- Steinheil, achromatic ocular, 144
- Karl August, silvering specula, 39
- Striæ, location of, 67
- Surface, treatment of deterioration of, 218
- T
- Taylor, triplets with reduced secondary spectrum, 89
- Telescopes, choice and purchase of, 201
- Early in 1610 made in England, 6
- first, 3
- the first astronomical, 9
- improvement of early, 11
- lineage of, 1
- name devised, 9
- Telescopes, portable and fixed, 108
- 1609, for sale in Paris, 5
- size and mounting of early, 14
- Telescopic vision, discovery of, 2
- Templets, designed curves of, 69
- Tests for striæ and annealing, 68
- Transparency, lack of in atmosphere, 255
- Triplet, cemented, 85
- Turret housing of reflector, 244
- V
- Variable stars, 192
- W
- Wedge calibrated by observation, 197
- photographic, 197
- photometer, 197
- Wind, shelter from, 240
- Z
- Zeiss, binocular of extreme stereoscopic effect, 161
- Zöllner, photometer modification of, 198
- Zonal aberration, 209