9i

Newtonian Reflecting Telescope on Berthon’s Patent Equatorial Stand. Page 30, Fig. 22.

With silvered-glass mirror, 6^-inch ... ... ... ... .., ...

» ,, 8|- „ ... ... ... ... ... ... ^7°

This form of stand is exceedingly steady. The lower end of the tube can be removed and packed with the whole of the working portion of the equatorial and the remainder of the tube in a comparatively small case. The circles are fully divided, and the hour circle is movable, with double verniers. Screw movements in right ascension and declination.

Newtonian or Cassegrainian Reflecting Telescope, on Berthon’s Patent Equatorial Stand. Page 39, Fig. 23, with silvered glass mirrors.

6Tin. 8A-in. /70 10-in. 12^-in. 15-in. 18-in. 24-in. 36-in. 48-in.

A. j£45 £80 £120 £210 £330 ^5io ^1600 £3000

B. 70 90 110 150 260 410 620 1800 3400

c. 90 110 140 200 320 500 75° 2400 4400



Specification A includes a silvered glass Newtonian or Cassegrainian mirror and secondary reflector mounted in an iron body tube. The telescope is supported on an equatorial stand, with screw motions in right ascension and declination. The hour circle can be rotated, and is fully divided and read by two verniers. The declination circle is fully divided with vernier.

Specification B includes a telescope and equatorial as in A, with the addition of a driving clock with governor regulator.

Specification C includes telescope, equatorial and driving clock, as in B, with ah the metal work of the best finish. The tube ventilated, if desired, and is revolved by mechanical means. The right ascension and declination hand movements are so arranged that both can be worked, either at the eye-piece or vernier, with the greatest facility. The hour circle is acted upon by the driving clock, and when once set will read accurate time until the clock stops. The circles can be read from the eye-piece. A novel method of micrometer illumination is affixed. Specification C can be an equatorial of the German form at a slight increase of price. The larger Cassegrainians are made either in the original form or in Nasmyth’s modification of the same. The above specifications do not include eye-pieces, &c., as Horne & Thornthwaite have thought it preferable to allow their customers to select the accessories most suitable to their requirements ; they will, however, be happy to select the necessary adjuncts should they be requested to do so, or customers may select their own from this catalogue.

---

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 95,85 %.

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

---