VLT telescope mirror. This mirror, called M2, is the uppermost mirror on each of the four 8.2-metre telescopes (Antu, Kueyen, Melipal and Yepun) making up the Very Large Telescope (VLT) at Paranal Observatory in Cerro Paranal, Chile. Below this mirror is a unit (not seen) containing two further mirrors, known as M1 and M3. The mirrors are flexible and are constantly adjusted by computers to compensate for errors. The images from the four telescopes are combined to produce an image equal to that obtained by one 16 metre diameter mirror. This makes the VLT one of the most powerful telescopes in the world. It is operated by the European Southern Observatory. It is at an altitude of 2600 metres in the Atacama Desert, one of the driest places on Earth.