Accession No

2945

Brief Description

zenith instrument, by Cooke, Troughton and Simms, English, 1930 (c)

Origin

England; London and York

Maker

Cooke, Troughton and Simms

Class

optical

Earliest Date

1922

Latest Date

1950

Inscription Date

Material

metal (brass, oxidised brass, two white metals); glass; liquid; plastic (ivorine)

Dimensions

height 1295mm; length 520mm; breadth 490mm

Special Collection

Provenance

Inscription

‘COOKE,
TROUGHTON & SIMMS, LTD.
LONDON YORK’ (eyepiece micrometer)

Description Notes

Zenith instrument, by Cooke, Troughton & Simms, English, c. 1930.

Brass and green-painted brass zenith instrument. Tribrach base with three levelling screws. Open circle on base carries silvered degree scale divided [0] - 360˚, numbered by 5˚, subdivided to 30´, with vernier reading to 1´; clamp and tangent screw. Diametrical bar (which carries vernier and clamping screw) turns the column mounted at the centre of the circle. This column supports a telescope set in an altitude mount at one side of the top of the column; other side of column carries a horizontal bar with counterweight and graduated (but not calibrated) level. Clamp and tangent screw for adjusting angle of horizontal bar. Telescope with screwfit objective; objective cover with pivoted cover over central section. Eyepiece micrometer with ivorine drumhead divided 0 - [10], numbered by 1, subdivided to 0.1. Angled push-fit eyepiece, allowing observation from side. Brass circle on side of telescope carries degree scale divided 0 - 90˚ - 0 - 90˚ - 0, numbered by 10˚, subdivided to 30´ with vernier reading to 1´; moving over this circle is a bubble level with scale divided 0 - 30, numbered by 5, subdivided to 1, read by mirror set above level; clamp and tangent screw.

Condition good; complete.

References

Events