Accession No
3106
Brief Description
prism, original ‘single large white-flint prism’ belonging to the Bruce spectroscope added to the 25" refractor at Cambridge, by John A. Brashear, 1895, reworked by Hilfer in 1932
Origin
Maker
Brashear, John A.
Class
optical
Earliest Date
1895
Latest Date
1895
Inscription Date
1895
Material
glass
Dimensions
length 86mm; breadth 75mm; depth 56mm
Special Collection
Provenance
Transferred from Institute of Astronomy, University of Cambridge, Cambridge, England, 12/1983. This prism was the original ‘single large white-flint prism’ by Brashear belonging to the ‘Bruce spectroscope’ added to the 25´´ refractor at Cambridge.
Inscription
‘BRASHEAR
1895
-LIGHT
FLINT
REWORKED
BY
HILGER
1932’ (side)
‘BLOOMED 1946’ (side in pencil)
Description Notes
60˚ glass prism.
Condition
References
Events
Description
Prism
A prism consists of a translucent piece of glass or crystal, usually triangular in cross section, which is used to separate light into a spectrum of its separate colours.
The instrument works because different wavelengths of light are refracted (bent) by different amounts as they enter and leave the prism; the shorter wavelengths (towards the blue end of the spectrum) are refracted by the greatest amount, and the longer wavelengths (towards the red end) are refracted the least. This spreads out normal white light, which is a mixture of all the different colours, into its constituent parts and produces the rainbow effect of a spectrum.
18/10/2002
Created by: Saffron Clackson on 18/10/2002
FM:43417
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