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Filar micrometer by William Herschel, 1780-1800

1780-1800

Wire micrometer

Trifilar eyepiece micrometer in brass

1775-1800

Brass moving wire filar micrometer by J. Sissons

1740-1760

Brass filar micrometer for astronomical telescope

1751-1773

Positional filar micrometer by John Browning

1875-1900

Cassegrain reflecting telescope, 1762-1774

1762-1774
Eye-piece micrometer inscribed E.6 in wood mount with brass frame divided circle (120 divisions numbered from 0 degree to 60 degrees) and steel screw, 2 threads in position

Filar micrometer by William Herschel, 1780-1800

1780-1800
Surveyor's level, 23-inch (without tripod stand), by Troughton & Simms, London, England, 1841. Fitted with 12-inch alcohol bubble level, magnetic compass and filar micrometer. Used for 1st order levelling

Surveying level, British, 1841t, with accessories

1841
Portable transit instrument of 2¼-inch aperture by Thomas Jones, London, with striding level, lamp and glass screen in a fitted box. Accessories include 7 glass levels, 1 magnifier, 2 eyepieces, 2 dark slides and a micrometer slide.

Portable transit instrument of 2¼-inch aperture by Thomas Jones

1816-1850
Smythian telescope, c.1824, a refractor of 3 3/4 inch aperture and 50 inch focal length by Thomas Robinson, Portland Place, London with optics by Charles Tulley in fitted box but without equatorial mount or stand. Separate fitted box contains 6 astronomical eyepieces, terrestrial eyepiece, cometary eyepiece, filter wheel, Herschel wedge, split-lens micrometer by Dollond, double-image micrometer by Thomas Robinson and related items including an occulting bar, graticle and ring (annular) micrometer. First used by Capt. W. H. Smyth at Bedford then given by him to Dr Lee at Hartwell House in 1828, later used by Dr N R Pogson from 1857 until 1860 at the Radcliffe and Hartwell Observatories and then at the Madras Observatory, India until 1891. Presented to the British Astronomical Association by the widow of Dr C. Michie Smith.

Smythian telescope, c.1824, a refractor of 3 3/4 inch aperture, 50 inch focal length, and accessories

1825-1829
Refracting telescope of 2 1/4 inch aperture and 36 inch focal length by Trougton, London on an adjustable equatorial mounting with spirit level and tripod stand and box. Accessories include, 2 eyepieces, key , diagonal and filar micrometer.

Refracting telescope of 2 1/4 inch aperture and 36 inch focal length by Trougton

1790-1826
Ramsden's patent (No.1112, 1775, Dec.30) Astronomical Equatorial Instrument with glazed Sheraton case, c.1775. Refracting telescope, 2-1/4 inch aperture and 18-inch focal length (probably by Peter Dollond), on an adjustable equatorial mounting with tripod stand. The stand is equipped with 3 spirit levels, 3 levelling screws and 2 scales read by verniers. Accessories include 5 eyepieces, two diagonal mirrors, glass prism, two dark filter caps and a filar micrometer with reflector to illuminate the cross hairs.

Ramsden's patent (No.1112, 1775, Dec.30) Astronomical Equatorial Instrument, with equatorial mounting, accessories, tripod and case

1770-1780
Early filar micrometer in leather case, Italian, 1700-1799

Early filar micrometer in leather case

1700-1750
1 P & L goniometer eyepiece, 1 P & L Filar micrometer eyepiece, 1 P & L coverglass micrometer, 1 P & L substage condenser, 1 P & L Nicol prism, 1 Zeiss Browning eyepiece spectroscope, 1 set Leitz objective changers

Microscope accessories by Zeiss, Powell & Lealand, and Leitz

Refracting telescope of 1 1/2-inch aperture and 36-inch focal length by John Smeaton on an adjustable equatorial mounting with a tripod stand. The telescope is fitted with an integral filar micrometer [RAS No.7] . Presented to Royal Astronomical Society in 1845 by Mrs Somerville to whom it was left by Mrs Dixon, Smeaton's daughter.

Refracting telescope of 1 1/2-inch aperture and 36-inch focal length

1770