Accession No
1063
Brief Description
six-prism automatic solar spectroscope, by John Browning, English, c. 1880
Origin
England; London; 63 Strand
Maker
Browning, John
Class
optical; astronomy
Earliest Date
1880
Latest Date
1880
Inscription Date
Material
metal (brass, oxidised brass); glass; wood
Dimensions
length 280mm; breadth 165mm; height 370mm; eyepiece length 71mm; max diameter 27mm
Special Collection
Provenance
Donated by the Solar Physics Laboratory, University of Cambridge in 07/1951.
Inscription
‘John Browning, 63 Strand, London’ (on collimator)
‘John Browning, 63 Strand, London’ (on second eyepiece)
Description Notes
Six-prism automatic solar spectroscope, by John Browning, English, c. 1880.
Browning’s Automatic Solar Spectroscope. Brass and oxidised brass. Circular plate with threaded mount for fixing on telescope. The spectroscope itself is carried on two arms extending from a plate mounted on the circular plate and moveable in two directions by knurled screws. At their far end the arms are attached to the circular stage of the spectroscope. Collimating tube with draw tube carrying adjustable slit and reflecting prism on pivoted arm. Circular stage with 7 prisms, one a reflecting prism at end of colimator, the others numbered 1-6, prisms 2-6 being linked at the corners of their bases and carried on moveable arms, intersecting in centre, where a brass pin passes through slits in each arm. Retaining nut screws onto threaded portion of pin. Prisms 2-6 slide out of mounting and have knurled brass knobs for removing them (one knob is missing). The train of prisms is moved by a brass arm extending from the mount of prism 6; the arm can be clamped by a screw to a fixed brass piece and moved by a micrometer screw. Telescope with rack and pinion focus, moved by knurled screw, and eyepiece on additional drawer. Second eyepiece with one drawer. Glazed cover for slit.
Wooden box, two eyepieces and envelope of ?feet. Top of the box found to have suffered oil spillage when box was stored in cupboard under showcase and a leaky oil can placed on top. Discovered 26-3-1998.
References
Events
Description
Spectroscope
In 1814 Joseph von Fraunhofer noticed that the sun’s spectrum, when dispersed by a glass prism, is crossed by hundreds of fine dark lines. These lines could be used to determine the chemical composition of the sun, stars and many other substances by spectral analysis. The first photograph of the spectrum of a star (Vega) was made by Henry Draper using a spectroscope in 1872.
There are various different forms of spectroscope, but all use a slit and collimator to make a parallel beam of light, a prism for dispersing different wavelengths and a telescope to observe the dispersed spectrum.
Browning’s Automatic Solar Spectroscope was designed for direct attachment to a telescope. It contains 6 dispersing prisms and 2 reflecting prisms. The light is passed twice through the train, given a total dispersive power of ten prisms. Browning wrote that this instrument ‘will show the solar spectrum with exquisite definition.’
18/10/2002
Created by: Saffron Clackson on 18/10/2002
FM:43394
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