Paranal Observatory is an astronomical observatory operated by the European Southern Observatory (ESO). It is located in the Atacama Desert of northern Chile on Cerro Paranal at 2,635 m (8,645 ft) altitude, 120 km (70 mi) south of Antofagasta. By total light-collecting area, it is the largest optical-infrared observatory in the Southern Hemisphere; worldwide, it is second to the Mauna Kea Observatory on Hawaii. The Very Large Telescope (VLT), the largest telescope on Paranal, is composed of four separate 8.2 m (320 in) telescopes. In addition, the four main telescopes can be used simultaneously for extra light gathering capacity, and for interferometry. Four auxiliary telescopes of 1.8 m (71 in) each are also part of the VLTI to make it available when the main telescopes are being used for other projects. The site also houses two survey telescopes with wide fields of view, the 4.0 m (160 in) VISTA and the 2.6 m (100 in) VLT Survey Telescope for surveying large areas of the sky; and two arrays of small telescopes called NGTS and SPECULOOS which are dedicated to searching for exoplanets. Two major new facilities are under construction nearby: the southern part of the Cherenkov Telescope Array gamma-ray telescope (not owned by ESO) will be sited in the grounds 10 km south-east of Paranal; while ESO's future E-ELT will be on the nearby peak of Cerro Armazones 20 km east of Paranal, and will share some of the base facilities.
