Extremely large telescopes are considered worldwide to be one of the highest priorities in ground-based astronomy. They will lead to a greater advancement of astrophysical knowledge, allow a deeper exploration of our Universe, and give sharper views of cosmic objects than ever before. Since 2005 ESO has been working with its community and industry to develop an extremely large optical/infrared telescope. ESO’s Extremely Large Telescope, or ELT for short, is a revolutionary ground-based telescope that will have a 39-metres main mirror and will be the largest visible and infrared light telescope in the world: the world’s biggest eye on the sky.

Location
An extraordinary telescope calls for an exceptional site. Great care was therefore taken to ensure that the home of the ELT was the best possible. This required a high, dry site — perfect for observations.
On 26 April 2010, the ESO Council selected Cerro Armazones as the site for the planned 40-metre-class ELT. Cerro Armazones is a mountain at an altitude of about 3046 metres in the central part of Chile’s Atacama Desert.