Accession No

1471

Brief Description

portable equatorial instrument, by Nairne and Blunt, English, c. 1780

Origin

England; London

Maker

Nairne and Blunt

Class

astronomy

Earliest Date

1780

Latest Date

1780

Inscription Date

Material

metal (brass, oxidised brass, steel); glass; wood; liquid

Dimensions

telescope length 557mm; breadth of base368mm; overall height 557mm

Special Collection

Provenance

Transferred from the Department of Geography, University of Cambridge, in 05/196

Inscription

‘Nairne & Blunt London’ (latitude arc)

Description Notes

Portable equatorial instrument, by Nairne and Blunt, English, c. 1780.

Brass telescope, achromatic object glass in threaded brass mount, push-fit cover with central aperture with pivoting cover; rotatable right-angle eyepiece; barrel has central aperture with sliding cover. Tube pivots about horizontal axis held by two supports and surmounted by bubble level. Counterweight and vertical circle at other side of axis. Vertical circle divided on brass 0 - 180˚ - 0, numbered by 10˚, subdivided to 30´, clamp and tangent screw, separate central-zero vernier with zero adjustment giving reading to 5´. Right ascension circle divided on brass, marked with hours I - XII twice, numbered by I, divided to 2 minutes, clamp and tangent screw, type-B vernier reading to 10 seconds. Right ascension circle set on polar axis with horizontal axis forming a cross and carried by two supports. Polar axis ends with counterweight which slides over latitude arc, divided [5˚ ] - 0 - [94˚], numbered by 10˚, divided to 20´, clamp and tangent screw, type-B vernier with zero adjustment giving reading to 2´, reading microscope. 2 bubble levels, one set in, the other mounted on plate carrying brass vertical axis, over horizontal circle, divided 0 - 180˚ - 0, numbered by 10˚, subdivided to 1˚ and to 30´, type-A vernier giving reading to 3´, clamp and tangent screws, clamp beneath platform for setting horizontal circle. Reinforced wooden tripod stand, with 3 brass levelling screws. Striding level. Straight eyepiece. 2nd right-angle eyepiece. 2 eyepiece filters. 3 filters in single brass mount.

Condition good (some marking); complete

References

Events