Refracting telescope
Refractors were the earliest type of optical telescope. The first practical refracting telescopes appeared in the Netherlands about 1608, and were credited to three individuals, Hans Lippershey and Zacharias Janssen, spectacle-makers in Middelburg, and Jacob Metius of Alkmaar. Galileo Galilei, happening to be in Venice in about the month of May 1609, heard of the invention and constructed a version of his own. Galileo then communicated the details of his invention to the public, and presented the instrument itself to the Doge Leonardo Donato, sitting in full council.
Portobello, Dublin
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.