The world’s largest telescope is an optical telescope by the name of Large Binocular Telescope (LBT). This telescope is used for astronomical purposes and is located on Mount Graham (10,700-foot (3,300 m)) in the Pinaleno Mountains of south-eastern Arizona, and is a part of the Mount Graham International Observatory. The LBT has two 8.4 m (27 ft) wide mirrors and has the same light gathering ability as a 11.8 m (39 ft) wide single circular telescope with a detail of 22.8 m (75 ft) wide one.