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,
Large Synoptic Survey Telescope of view, but at the expense of light-gathering power as the large second mirror blocks much of the aperture of the telescope. The LSST primary mirror (M1) is in diameter, the secondary mirror (M2) is in diameter, and the tertiary mirror (M3), inside the ring-like primary, is in diameter. The secondary mirror is expected to be the largest convex mirror in any operating telescope, until surpassed by the ELT's 4.2 m secondary . The second and third mirrors reduce the primary mirror's light-collecting area to , equivalent to a telescope. Multiplying this by the field of view produces an etendue