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  • Thornthwaite, W. H. - Hints on reflecting and refracting telescopes and their accessories
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  • p.81 - vue 83/100
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  • TABLE DES MATIÈRES
  • TABLE DES ILLUSTRATIONS
  • RECHERCHE DANS LE DOCUMENT
  • TEXTE OCÉRISÉ
  • Première image
  • PAGE DE TITRE
    • Preface to the third edition (p.R2)
    • Contents (p.R3)
    • Introduction (p.5)
    • The various forms of telescopes. Their construction and advantages (p.7)
    • Refracting telescopes (p.11)
      • The perspective and opera-glasses (p.11)
      • The ordinary refracting telescope (p.12)
      • Stands for refracting telescopes (p.16)
      • Reflecting telescopes (p.19)
        • Direct vision reflectors. The gregorian telescope (p.19)
        • The cassegrainian telescope (p.20)
      • Stands for direct vision reflectors (p.21)
        • Indirect-vision reflectors. Nasmyth's modification of the cassegrainian telescope (p.21)
        • The herschelian telescope (p.22)
        • The newtonian telescope (p.23)
        • Adjustments of a newtonian telescope (p.24)
    • Stands for indirect-vision reflectors (p.31)
      • The alt-azimuth stand (p.31)
      • Equatorial stands (p.36)
      • Horne and thornthwaite's portable equatorial (p.36)
      • Berthon's patent equatorials (p.37)
    • Equatorial adjustments (p.41)
      • To place the Polar Axis in the Méridian (p.41)
      • To correct the Declination Vernier (p.41)
      • To adjust the Polar Axis to the Latitude of Observation (p.43)
      • To test the accuracy in position of the Telescope (p.43)
        • To set the Right Ascension Vernier (p.45)
        • To find a Celestial Object by means of the Declination and Hour Circles (p.46)
        • To convert Mean into Sideral Time (p.47)
        • Table of Refractions (Bessel) (p.48)
        • To adjust the “Finder” (p.48)
    • To silver and polish glass specula (p.49)
      • Apparatus (p.49)
      • To support the Mirror in the Silvering Vessel (p.50)
      • To clean the mirror (p.51)
      • To immerse the mirror (p.51)
      • To prepare the Silvered surface for polishing (p.52)
      • To polish the Silvered surface (p.53)
      • To separete the Mirror from the Wooden Support (p.54)
      • Martin's process of silvering (p.54)
      • Dr. Henry Draper's formula for silvering (p.56)
      • The sugar of milk process for silvering (p.56)
      • General, hints on silvering (p.57)
    • Accessories to the telescope (p.58)
      • Eye-pieces (p.59)
      • Solar eye pieces (p.59)
      • Barlow's lens (p.59)
      • The micrometer (p.60)
      • The double image micrometer (p.61)
      • Berthon's dynamometer (p.61)
      • The astronomical spectroscope (p.62)
      • Horne & thornthwaite's miniature universal spectroscope (p.65)
    • Observatories (p.66)
      • To construct an observatory on the Romsey model (p.67)
      • References to illustrations (p.71)
      • Horne & thornthwaite's astronomical clock (p.72)
      • Hints on observation (p.74)
    • Defining and separating tests (p.78)
    • Light tests (p.79)
    • Catalogue of reflecting and retracting telescops and their accessories (p.81)
      • Achromatic perspective glasses (p.81)
      • Achromatic opera glasses (p.81)
      • Achromatic field glasses (p.81)
      • Achromatic telescopes (p.83)
      • Horne and thornthwaite's binocular telescopes (p.83)
      • Refracting telescopes for astronomical purposes (p.84)
      • Astronomical object glasses (p.87)
      • Astronomical reflecting telescopes (p.89)
      • Silvered-glass specula (p.93)
      • Silvered-glass diagonal mirrors (p.93)
      • The “romsey” observatory (p.93)
      • Silvering and polishing specula (p.94)
      • Apparatus for silvering (p.94)
        • Silvering vessels (p.94)
        • Glass measures (p.94)
        • Chemicals (p.94)
      • Set of silvering apparatus (p.94)
      • Astronomical eye pieces (p.95)
        • Huyghenian construction (p.95)
        • Ramsden's construction (p.95)
        • Aplanatic construction (p.95)
        • Kellner's construction (p.95)
      • Solar eye pieces (p.95)
      • Micrometers (p.95)
      • Astronomical spectroscopes (p.96)
      • Trabsit instruments (p.96)
      • Works on astronomy (p.96)
  • Dernière image
  • Première image
  • PAGE DE TITRE
    • The german equatorial stand (p.17)
    • The victoria equatorial (p.18)
    • The alt-azimuth stand (p.32)
    • Horne and Thornthwaite's equatorial reflector (p.34)
    • Horne and Thornthwaite's portable equatorial reflector (p.35)
    • The berthon equatorial (p.38)
    • The berton equatorial (p.39)
    • The victoria equatorial telescope (p.85)
    • Berthon patent equatorial stand (p.90)
    • The alt-azimuth stand (p.92)
    • Binoclar microscope (p.97)
  • Dernière image
CATALOGUE

OF

aitd Ififimhibff

AND THEIR ACCESSORIES.

ACHROMATIC PERSPECTIVE GLASSES.

Page ii.

Perspective Glass, with enamelled or leather-covered body ,, „ ivory and gilt draw

»> n ,, „ larger size...................

More powerful glasses ........................... £i is., £i ios.

£ s-

o 7 o 13 o 16 2 2

d.

6

o

o

o

ACHROMATIC OPERA GLASSES.

Page 11.

Opera Glasses, with leather-covered bodies, six lenses in flexible cases,

12s. 6d., 15s., £1 is., £1 7s. 6d. £220 »> „ ,, . twelve lenses

£z 3s- ^4 4 0

Fig. 33-

ACHROMATIC FIELD GLASSES.

Page 11.

Field Glasses, with leather-covered bodies, sun shades, six lenses, in sling

cases (Fig 33) ... ... ....... £1 is., £1 10s., £2 2s., £2 12 6

» ;» ” . » twelve lenses

£3 3s-i £4 4s-) £5 5s-> £6 6 0

In addition to the above, Opera and other glasses can be obtained,

in many varieties of fancy mountings. Any of the above in Ivory bodies 20 per cent extra

,, Pearl ,, ... ... ... 75 V ,» ;

„ Aluminium mounts 100 „




Le texte affiché peut comporter un certain nombre d'erreurs. En effet, le mode texte de ce document a été généré de façon automatique par un programme de reconnaissance optique de caractères (OCR). Le taux de reconnaissance estimé pour cette page est de 89,27 %.

La langue de reconnaissance de l'OCR est l'Anglais.