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Speculum Metal Mirror, 1850-70

1850-1870

Speculum Mirror, 1861

1861

Primary metal speculum mirror with central hole

1840-1850

Speculum Metal Mirror, 1840-60

1840-1860

Rough sketch of James Nasmyths' apparatus by which most perfect sound speculae may be cast with absolute certainty

1879

Optical parts of Lassell's telescope

1840-1850

Mirror for Short's reflecting telescope

1760-1762

Mirror for Short's reflecting telescope

1767-1768

Speculum mirror for Gregorian telescope

1753-1755

speculum mirror, 1783-1785

1783-1785

Speculum mirror of 2 1/2-inch aperture

1756-1758

Speculum Mirror (dia. 5 3/4-inch) for Gregorian telescope in wooden box

1750-1850

Primary speculum mirror of 13 1/4-inch diameter

1840-1850

The first 48-inch speculum mirror cast by Sir William Herschel in 1785 for his 'Forty-Foot' telescope at Slough, England.

Original mirror for William Herschel's forty-foot telescope, 1785.

1785

Speculum mirror of 6 1/4-inch diameter in brass cell with tinplate cover for 7-foot telescope owned by Caroline Herschel, late 18th century.

Newtonian reflecting telescope, 1795-1816

1795-1825

The first 48-inch speculum mirror cast with metal cover by Sir William Herschel in 1785 for his 'Forty Foot' telescope at Slough, England.

Original mirror for William Herschel's forty-foot telescope, 1785.

1785

Four primary metal speculum metal mirrors, three of 4 1/2- inch diameter and one of 8 5/8 inch mirror with central circular hole. Donated by Lieutent General A, de Gorloff who lived at Nasmyth's former home of Hammerfield near Penshurst in Kent. Four similar mirrors were originally donated but one was returned to be replaced by the larger one [see file for details].

Four primary metal speculum metal mirrors

1840-1850

Four speculum metal secondary mirrors thought to have been made by James Nasmyth. Donated by Lieutent General A de Gorloff who lived at Nasmyth's former home of Hammerfield near Penshurst in Kent.

Four speculum metal secondary mirrors thought to have been made by James Nasmyth

1850-1870

Optical parts of Lassell's telescope:- prism for 9-in reflector in green cardboard box; 3 multiple eyepieces; 5 small eyepieces; speculum for Newtonian finder in tin case 4 eyepices; 4 diaphragms (3 in two tin cases and one in wood case with metal lid)

Optical parts of Lassell's telescope

1840-1850

Nine inch mirror of speculum metal (exact diam" 8 15/16 in) in tin cell with close fitting cover 9 1/2" diam, 1 1/2" deep, focal length 10' 1", cell and cover each painted " J"

Mirror of speculum metal in tin cell

1780-1820

Experimental speculum of 6 inches aperture and 24 inches focal distance, cracked across and bound together with string

Experimental speculum of 6 inches aperture and 24 inches focal distance

1840-1870

Experimental compound speculum mirror of 2 feet diameter, made by the 3rd Earl of Rosse. The 9 segments of speculum metal, are held in an alloy of copper and zinc.

Experimental compound speculum mirror of 2 feet diameter

1840-1845

Metal cover for oval shaped secondary speculum mirror from the 6-foot Rosse telescope

Cover for speculum mirror

Nine inch mirror of speculum metal (exact diam" 8 15/16 in) in tinplate circular case

Mirror of speculum metal in tinplate circular case

1780-1820

Brass case for storage of secondary mirror with support and eyepiece blanking cap from Gregorian reflecting telescope of 3-inch aperture by John Cuthbert, London.

Brass case for storage of secondary mirror

1852

Set of 3 speculum mirrors [ 2 secondary & 1 tertiary] for reflecting telescope, 20-inch aperture with speculum mirror and altazimuth mounting, by James Nasmyth at Patricroft, Manchester, England, 1850-1852.

Set of 3 speculum mirrors [ 2 secondary & 1 tertiary] for reflecting telescope

1850-1852

Set of 2 secondary mirror support for reflecting telescope, 20-inch aperture with speculum mirror and altazimuth mounting, by James Nasmyth at Patricroft, Manchester, England, 1850-1852.

Set of 2 secondary mirror support for reflecting telescope

1850-1852

Eight-inch speculum mirror in a brass cell with tinplate cover, for Newtonian reflecting telescope of 10-foot focal length, made by William Herschel, England, 1812. The telescope was installed at the Radcliffe Observatory, Oxford, in 1813.

Eight-inch speculum mirror for Newtonian reflecting telescope made by William Herschel for the Radcliffe Observatory

1812

Oval shaped secondary speculum mirror from the 6-foot Rosse telescope

Oval shaped secondary speculum mirror

Elliptical plane mirror (diagonal flat for Newtonian telescope) minor axis 1 1/2", major axis 2" in (full) soldered in usual way to circular brass disc, cylindrical cover of brass 1 3/4" deep, cover of brass 1 3/4" deep, cover and brass disc inscribed 1 "A4"

Elliptical plane mirror (diagonal flat for Newtonian telescope) minor axis 1 1/2"

1780-1820

Speculum mirror of of 4 3/8-inch aperture for Gregorian telescope by James Short, London [42/1195 = 24].

Speculum mirror of of 4 3/8-inch aperture for Gregorian telescope by James Short

1763-1765

Oval shaped secondary speculum mirror with cover, from the 6-foot Rosse telescope

Oval shaped secondary speculum mirror with cover

1845-1850

Two plane speculums by Lassell, with Lassell's M.S. directions

Two plane speculums by Lassell

1840-1850

Optical parts of Lassell's telescope:- prism for 9-in reflector in green cardboard box; 3 multiple eyepieces; 5 small eyepieces; plane speculum on arm for 9-in; speculum for Newtonian finder in tin case 4 eyepices; 4 diaphragms (3 in two tin cases and one in wood case with metal lid)

Optical parts of Lassell's telescope:- prism for 9-in reflector in green cardboard box

1840-1850

Two plane speculums and two polishers by Lassell, with Lassell's M.S. directions

Two plane speculums and two polishers by Lassell

1840-1850