An instrument consisting of four 8.2-m reflectors, with the combined collecting area of a 16-m mirror, owned and operated by the European Southern Observatory at an altitude of 2635 m at the Paranal Observatory in Chile. The four individual reflectors are known as the Unit Telescopes (UT). Unit Telescope 1, named Antu, was opened in 1998, followed by UT2 (Kueyen) in 1999, with UT3 (Melipal) and UT4 (Yepun) in 2000. Next to the Unit Telescopes are four movable 1.8-m Auxiliary Telescopes (AT). Light from the Unit Telescopes and the Auxiliary Telescopes can be combined in the VLT Interferometer (VLTI) for high-resolution imaging. The Auxiliary Telescopes can be placed in 30 different positions, providing interferometer baselines up to 200 m. The first AT was installed in 2004 and the last in 2006. Adjacent to the VLT is the 2.61-m VLT Survey Telescope (VST), a wide-field survey instrument built by ESO and Italy, which began observations in 2011.
http://www.eso.org/public/teles-instr/vlt.html Official telescope website.
Subjects: Astronomy and Astrophysics.