VLT telescope. Internal structure of one of the four 8.2-metre mirror telescopes (Antu, Kueyen, Melipal and Yepun) making up the Very Large Telescope (VLT) at Paranal Observatory in Cerro Paranal, Chile. The telescopes are comprised of three mirrors in order to capture focused images. The unit at top holds the primary mirror (called M1) and the column at centre holds the tertiary mirror (M3). The secondary mirror (M2) is housed at the top of the telescope (not seen). These 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.