Paranal Observatory — observatory
European Southern Observatory · CC BY 4.0

Paranal Observatory

Observatorio Paranal

  • Elevation2,635 m
  • 2 min read
  • 24.627° S 70.404° W

Interesting facts

  • Before the observatory was built, the summit of Cerro Paranal stood about 29 metres higher; levelling in 1991–92 removed roughly 350,000 cubic metres of rock.
  • The four 8.2-metre Unit Telescopes carry names from the Mapuche language: Antu (Sun), Kueyen (Moon), Melipal (Southern Cross) and Yepun (Evening Star).
  • Each main VLT mirror weighs about 22 tonnes yet is only 177 millimetres thick, kept in perfect shape by 150 computer-controlled supports beneath it.
  • In 2004 the VLT photographed 2M1207b, a planet-mass companion of a young brown dwarf, widely hailed as the first direct image of an exoplanet.
  • Linked together as an interferometer, the telescopes reach a resolution of about 0.002 arcseconds, some 25 times finer than a single Unit Telescope.
  • For well over a decade astronomers used the VLT to follow the star S2 as it circles the supermassive black hole at the centre of the Milky Way.
  • By number of scientific papers the VLT is second only to the Hubble Space Telescope; in 2017 alone more than 600 refereed papers drew on its data.
  • The first of the four Unit Telescopes began operating in May 1998, and the observatory opened to the astronomical community on 1 April 1999.
  • The NGTS planet hunter is an array of twelve 20-centimetre robotic telescopes covering about 96 square degrees, several hundred times the area of the full Moon.
  • The four SPECULOOS telescopes, searching for planets around small cool stars, are named Europa, Io, Callisto and Ganymede after the moons of Jupiter.

Why it is worth it

Cerro Paranal is a bare summit 2,635 metres high in the Atacama Desert of northern Chile, and on its levelled top the European Southern Observatory has built its flagship observatory. The nearest settlement, the coastal hamlet of Paposo, is 38 km away in a straight line, and that isolation from the lights of civilisation is exactly the point. By total light-collecting area Paranal is the largest optical and infrared observatory in the Southern Hemisphere, second in the world only to Mauna Kea.

Its centrepiece is the Very Large Telescope: four identical telescopes with 8.2-metre mirrors, lined up along the summit platform in their own enclosures, together with four movable 1.8-metre auxiliary telescopes in small white domes. The large telescopes can work alone or be combined with the smaller ones as an interferometer, pooling their light to see finer detail than any one of them could. On a secondary peak about 1.5 km away stands VISTA, a 4-metre survey telescope for the infrared sky, and beside the VLT the 2.6-metre VLT Survey Telescope maps the sky in visible light. Arrays of small robotic telescopes, NGTS and SPECULOOS, hunt for planets around other stars. All four large telescopes are equipped with adaptive optics, and on some nights the beam of a laser guide star rises from one of them into the sky.

Life on the mountain has its own architecture. The Residencia, where astronomers and staff live, is set about 200 metres below the telescopes and built half into the slope, with concrete tinted to match the desert; inside are gardens, a swimming pool and a restaurant for people who spend weeks at a time on the mountain. Its striking form made it a location for the James Bond film Quantum of Solace. On neighbouring Cerro Armazones, about 20 km to the east, ESO is building its Extremely Large Telescope, which will share some of Paranal's base facilities.

Getting there

Antofagasta is the nearest city, about 110–120 km to the north, and Andrés Sabella Gálvez International Airport (ANF) is about 130 km away. ESO offers free guided public tours on Saturdays; registration in advance through ESO's online form is compulsory, and visitors park at the designated area and continue by tour bus.

On these lists

The Most Beautiful Places in Antofagasta 8The Most Beautiful Places in Chile 26The Most Remarkable Observatories 8The Greatest Engineering Wonders 271

From the encyclopaedia

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.

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-24.62722, -70.40417per Wikidata