For the 60-inch telescope , George Ellery Hale received the mirror blank , cast by Saint-Gobain in France , in 1896 as a gift from his father , William Hale . It was a glass disk 19 cm thick and weighing 860 kg . However it was not until 1904 that Hale received funding from the Carnegie Institution to build an observatory . Grinding began in 1905 and took two years . The mounting and structure for the telescope was built in San Francisco and barely survived the 1906 earthquake . Transporting the pieces to the top of Mount Wilson was an enormous task . First light was December 8 , 1908 . It was at the time the largest operational telescope in the world . Lord Rosse 's Leviathan of Parsonstown , a 72-inch ( 1.8-meter ) telescope built in 1845 , was , by the 1890s , out of commission
1906 earthquake
1906 San Francisco earthquake
Mount Wilson Observatory