Credit: © The Royal Society
Image number: RS.9080
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Telescope speculum grinding tool for Lord Rosse's 72-inch telescope at Birr Castle, Ireland
Date
1861
Object type
Archive reference number
Material
Technique
Dimensions
height (print): 104mm
width (print): 98mm
width (print): 98mm
Subject
Content object
Description
Plate 24 figure 4 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 front view of the cast iron grinding tool used to produce the speculum of the reflecting telescope at Birr Castle, Parsonstown. The face has straight cast grooves forming squares and circular, lathe-cut groves The tool is shown suspended on gimbals from a pulley. The image is inscribed in pencil, verso "Original Lord Rosse's paper".
Object history
This photograph was supplied for reproduction in the journal Philosophical Transactions of the Royal Society.
Associated place