CATALOGUE OF Silvered Glass Reflecting Telescopes, &c., AND THEIR ACCESSORIES,
Reading edition
JUNE, 1877.
G. Calver, while introducing the list of prices below, has the greatest confidence in calling the attention of the practical astronomer and the amateur to the very moderate prices charged, considering the principle and style of the mounting, and the firm and well-fitted arrangements in all the parts.
The principle of the mounting is that which is the most convenient to use, and with the greatest degree of steadiness with the easiest movements. Fig. 1 is the best mounting ever applied to the Reflecting Telescope.
He is also able to state, that with his processes and special facilities for working large specula, and substantially mounting them, he is prepared to construct automatic equatorials of large sizes, and with any special arrangements that may be required.
Silvered Glass Equatorial Telescopes, very substantially and well-fitted, as (Fig. 2). All these equatorials have revolving body.
£ s. d.
5-1/4 inch Speculum from 4 to 6 feet focus, with 8 inch hour circles reading to 5 seconds of time, and declination circle reading to 1 minute, two powers 30 0 0
6-1/2 inch Speculum of from 5 to 6-1/2 feet focus, 10 inch rotating hour circle, reading to 5 seconds of time, and declination circle to 1 minute of arc, with 3 powers—100 to 500 45 0 0
8-1/2 inch Speculum as above with 12 inch circles, 4 powers 70 0 0
9-1/4 inch Speculum as above with 12 inch circles, 5 powers 78 0 0
10 inch Speculum as above with 12 inch circles, 5 powers 90 0 0
12-1/2 inch Speculum as above with 12 inch circles, 5 powers 120 0 0
Any of the above sizes mounted on Stand (Fig. 1), from 5 per cent. extra.
Fig. 1 is a very excellent stand, and admirably suited for large instruments with clock power, and is convenient to remove and adapt to different latitudes, &c., see p. 20.
£ s. d.
14, 15, to 16 inch Speculum mounted as (Fig. 1), with rotating hour circle reading to 5 seconds and declination to 1 minute (the diameter of the circles never less than that of the Speculum and often larger)
8 powers from 50 to 700, with first-rate and very powerful driving clock, first-class instrument, and complete from £220 to 330 0 0
17, 18, to 20 inch Speculum, with 10 powers, from 50 to 800, including Kellners, Huyghenians, and Achromatics, from £350 to 500 0 0
22 to 24 inch Speculum from £550 to 750 0 0
30 inch Speculum, with 12 powers and position micrometer, and transit eye-pieces 1000 0 0
Prices will be forwarded for special arrangements in any of these large sizes.
The Cassegrain Telescope is a very convenient form, and perfect in performance, and in this form a very large instrument requires comparatively a much smaller observatory, and is more conveniently worked. They can be made so that the image is thrown out at the side and viewed diagonally, as with the Newtonian, see p. 35. Cassegrains from 5 per cent. extra.
£ s.d.
DrivingClocks for 6to10inch 350 0
〃〃12 〃18〃400 0
〃〃20 〃30〃500 0
The Educational Reflector is a plain and very steady and satisfactory instrument, mounted on (Fig. 2) stand, without circles, has revolving body, and made so as to be portable.
£ s. d.
6-1/2 inch Speculum (clear aperture), and of 4 to 6-1/2 feet focus, has screw-motion in right ascension, 2 powers2500
8-1/2 inch speculum as above, with 3 powers4000
Any of these equatorials can be, according to wish, fitted without the circles, &c., and dispensing with that which is not needed, so as to reduce the price to suit circumstances and convenience.
The Popular Reflector, with Angle-Block Stand, with endless screw-motion to follow the stars with equatorial motion.
£ s. d.
5-1/4 inch Speculum, of from 4 to 6 feet focus, with 2 powers 15150
(See p. 20, Fig. 4).
Reflecting Telescope on Alt-azimuth Stand, as described at page 13, fitted with Silvered Glass Speculum, and provided with Two Eye-pieces.
£ s. d.
5-1/4 inch Speculum,4 to6 feet focus19100
6-1/2 〃 〃 4〃6-1/2 〃 240 0
8-1/2 〃 〃 〃6-1/2 〃 33100
10 〃 〃 〃7 〃 450 0
12-1/2〃 〃 〃8 〃 70100
Reflecting Telescope on Cradle Stand, and provided with Two Eye-pieces.
£ s. d.
5-1/4 inch Speculum,4 to6 feet focus 2100
6-1/2 〃 〃 4〃6-1/2 or 5feetfocus2700
8-1/2 〃 〃 〃6-1/2 〃 〃 3600
10 〃 〃 〃7 〃 〃 4900
12-1/2〃 〃 〃8 〃 〃 7600
SILVERED-GLASS SPECULA (unmounted).
THE FINEST QUALITY GUARANTEED.
£ s. d.
5-1/4 inch diameter 4 to6 feet focus 500
6-1/2 〃4〃6-1/2 〃 6 50
8-1/2 〃 〃6-1/2 〃 13 00
10 〃 〃7 〃 25 00
12-1/2〃 〃8 〃 38100
14 〃 〃8 〃 55 00
16 〃 〃10 〃 75 00
18 〃 〃12 〃 100 00
20 〃 〃12 〃 130 00
22 〃 〃15 〃 165 00
24 〃 〃18 〃 200 00
26 〃 〃 〃 250 00
30 〃 〃 〃 300 00
36 〃 〃 〃 400 00
SILVERED-GLASS DIAGONAL MIRRORS (unmounted).
FINEST QUALITY GUARANTEED.
£ s. d.
1 inchin the minor axis, or narrowest diameter of the ellipse 1 00
1-1/2 dittodittoditto1100
2 dittodittoditto2 00
2-1/2 dittodittoditto2100
3 dittodittoditto3 30
3-1/2 dittodittoditto4 40
4 dittodittoditto5 50
SILVERING AND POLISHING SPECULA.
£ s. d.
5 inch 06 0
6-1/2 〃 08 0
8-1/2 〃 0106
10 〃 0150
12-1/2〃 11 0
Diagonal Planes 3s. to 050
ASTRONOMICAL EYE-PIECES.
OF BEST QUALITY.
Huyghenian Construction of the following magnifying powers on a 6-1/2 feet focus object-glass:—
£ s.d.
35, 60, 90, 130, 180, 200each0150
320, 450 1 10
610 1 76
All fitted with Sunshades.
Improved Achromatic, Ramsden’s Construction.
£s.d.
90, 130 each1 00
189, 250 1100
320, 450 1126
610, 750 1150
850 2 20
Kellner’s Construction.
£ s.d.
30, 58, and 80each1 50
SOLAR EYE-PIECES.
£ s.d.
Solar Diagonal, with true plane 1126
Dawes’ Solar Eye-piece 8 00
Barlow’s Lens 1 10
Day Erecting Eye-piece 1 50
Coloured Eye-piece Cap for observing the Moon 0 40
Transit Eye-pieces, for use with Equatorials £1 1s. to2 20
Adjusting Piece 0 26
MICROMETERS.
£ s.d.
Parallel Wire Micrometer 5 50
Position Micrometers £8 8s. to15150
Double Image Micrometer 8 80
Illuminating Apparatus from 8 00
Good Instruments will be taken in exchange and liberally allowed for.
GEORGE CALVER,
HILL HOUSE, WIDFORD,
CHELMSFORD, ESSEX.
