| Reference number | PT/62/8/54 |
| Previous numbers | PT/62/8/5 |
| Level | Item |
| Title | Photograph, telescope speculum grinding tool for Lord Rosse's telescope at Birr Castle, Ireland by unknown artist |
| Date | [1861] |
| Description | A front view of the cast iron grinding tool used to produce the speculum of the reflecting telescope at Birr Castle, Parsonstown, Ireland. 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'. An engraved version of this photograph was published in William Parsons' paper as figure 4 from plate 24.
Subject: Scientific Instruments / Astronomy
Published in Philosophical Transactions as 'On the construction of specula of six-feet aperture; and a selection from the observations of nebulæ made with them'.
Received by the Royal Society on 5 June 1861. Read 20 June 1861. |
| Extent | 1p |
| Format | Photograph |
| Physical description | Albumen print, mounted on card |
| Dimensions | 104x98mm |
| Access status | Open |
| Related material | DOI: 10.1098/rstl.1861.0029 |
| DOI: 10.1098/rspl.1860.0078 |
| Related records in the catalogue | PT/62/8 |
| URL description | Digital version available on The Royal Society Picture Library |
| URL | https://pictures.royalsociety.org/image-rs-9080 |
Fellows associated with this archive
| Code | Name | Dates |
| NA8084 | Parsons; William (1800 - 1867); 3rd Earl of Rosse | 1800 - 1867 |