Thomas Grubb (1800–1878), a notable optician, developed his first telescope in a small house between Portobello Bridge and Charlemont Bridge and erected a public observatory at No. 1 Upper Charlemont Street. He founded the Grubb Telescope Company. One of his earliest instruments – the telescope for Markree Observatory in County Sligo – was, for several years, the largest telescope in the world. They provided the telescopes for many observatories worldwide, including Melbourne, Vienna and Aldershot Observatory in 1891. The company was acquired in 1925 by Charles Algernon Parsons and renamed Sir Howard Grubb, Parsons and Co. Ltd.