Credit: © The Royal Society
Image number: RS.9078
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Telescope speculum for Lord Rosse’s 72-inch telescope at Birr Castle, Ireland
Date
1861
Object type
Archive reference number
Material
Technique
Dimensions
height (print): 118mm
width (print): 134mm
width (print): 134mm
Subject
Content object
Description
Plate 24 figure 2 from the paper "On the construction of specula of six-feet aperture; and a selection from the observations of nebulae made with them", by William Parsons, 3rd Earl of Rosse, Philosophical Transactions of the Royal Society, volume 151 (1861) pp.681-746. A view of the speculum on supporting levers supported on a cast iron rail carriage. The carriage is shown on a turntable situated to the north side of the Parsonstown 72-inch reflecting telescope. The background is screened off by a dark cloth over which some details of trees and part of the supporting structure for the telescope are visible. The image was intended to show the weights and levers for counterpoising the secondary triangles. The instrument, the largest reflecting telescope in the world when built, was at Birr Castle, Parsonstown, Ireland. The image is inscribed in ink, verso "Original from which copy was made on reduced scale".
Object history
This photograph was supplied for reproduction in the journal Philosophical Transactions of the Royal Society.
Associated place