Leviathan Telescope (otherwise known as Lord Rosse's Telescope) at Birr Castle, Ireland

Monoscopic view from a stereo image used to produce Plate 24 figure 7 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. The great telescope seen from the south, showing the position of the telescope when a man enters the tube to fix the small speculum and remove the cover of the large mirror. The Earl of Rosse is standing in the telescope tube. A group of four other figures are on, or in front of, a mobile platform on rails. These include two of Rosse's children, Clere Parsons standing and Charles Algernon Parsons seated on the platform rail near two male observers.