Mount Wilson (California) a new Mt. Wilson Hotel. In 1908 a 60-inch (1524 mm) telescope was completed at the summit, and in 1910 the Solar Tower was erected. In 1913 the hotel burned down and was replaced by a second hotel that lasted until its demolition in 1966. The Toll Road opened to automobiles in 1912 and lasted until 1936. In 1917, the 100-inch Hooker Telescope was completed and saw first light and would be the world's largest telescope until the opening of the 200-inch Hale Telescope at Palomar Observatory in 1948. In 1919, American astronomer Edwin Hubble arrived at Mt. Wilson and,
Otto Struve Telescope light in 1939, behind the 100-inch Hooker telescope and ahead of two large British Commonwealth telescopes, both in Canada. Many competing projects were delayed due to the war in the early 1940s. Four largest telescopes in 1939: Otto Struve Telescope The Otto Struve Telescope was the first major telescope to be built at McDonald Observatory. Located in the Davis Mountains in West Texas, the Otto Struve Telescope was designed by Warner & Swasey Company and constructed between 1933 and 1939 by the Paterson-Leitch Company. Its mirror was the second largest in the world at the time. It was named after