Hale Telescope mirror.. It was completed in 1948 and is still in active use. The Hale Telescope represented the technological limit in building large optical telescopes for over 30 years. It was the largest telescope in the world until the Russian BTA-6 was built in 1976, and the second largest until the construction of the Keck Observatory Keck 1 in 1993. Hale supervised the building of the telescopes at the Mount Wilson Observatory with grants from the Carnegie Institution of Washington: the telescope in 1908 and the telescope in 1917. These telescopes were very successful, leading to the rapid advance in understanding
Westerlund telescope is detached from the rest of the building in order to reduce vibrations. Above the concrete plate is a metal floor grid to stand on. The telescope is a 0.9 meter classical Cassegrain but with a third rotatable plane mirror sending light to one of the two Nasmyth foci. The effective system is an f/10 but the primary mirror is an f/3. The telescope was built by Astro Optic and there is a sibling telescope at Albonova in Stockholm. The telescope is one of the largest optical telescopes in Sweden. The main camera has since the start been an SBIG