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