Chile chosen as site for 'extremely large' telescope

A European astronomical group has chosen a site in the Chilean coastal mountain range to build the world's largest optical telescope.

The European Southern Observatory chose Cerro Armazones, altitude 3,060 metres, in northern Chile to build the European Extremely Large Telescope (E-ELT).

The site was chosen in part because of its distance from large cities and its near-perfect viewing conditions. The sky over Cerro Armazones is cloud-free 320 nights a year.

The ESO's Very Large Telescope (VLT) is about 20 kilometres away in Cerro Paranal.

"This is an important milestone that allows us to finalise the baseline design of this very ambitious project, which will vastly advance astronomical knowledge," said Tim de Zeeuw, ESO's director general, in a statement.

Cerro Armazones beat competing locations in Chile and in the Canary Islands.

The E-ELT will be an optical-infrared telescope with a primary mirror 42 metres in diameter, what the ESO calls "the world's biggest eye on the sky." The E-ELT's mirror will be about five times wider than those of VLT, currently the world's largest optical telescope.

Construction of E-ELT is expected to begin at the end of 2010, and observations could begin as soon as 2018. The project could cost as much as one billion euros.

While a lot of attention is paid to orbiting telescopes like Hubble, many discoveries are still made by ground-based telescopes.

The ESO's 3.6-metre telescope in La Silla, Chile, has been used to discover more than 75 planets outside our solar system.