A very large telescope (VLT) is a type of optical telescope with a primary mirror that has a diameter of at least 8 meters. The VLT consists of four individual telescopes, each with a primary mirror 8.2 meters in diameter, that are operated together as an astronomical interferometer. The VLT is the largest and most powerful telescope in the world and is located on Cerro Paranal in the Atacama Desert of northern Chile.
The four Unit Telescopes (UTs) of the VLT are positioned along the four arms of a cross within a square configuration on top of Cerro Paranal. The UTs can work together as an interferometer, combining their light to achieve very high angular resolution power or they can work independently.
Each UT has several auxiliary instruments including:
– VISIR (Very Large Telescope Infrared Spectrometer and Imager),
– NACO (Near-Infrared Adaptive Optics System),
– SINFONI (Spectrograph for INtegral Field Observations in the Near Infrared),
– FORS1/2 (FOcal Reducer/low dispersion Spectrographs), and
– HAWK-I (High Acuity Wide field K-band Imager).