An artist’s impression of the European Extremely Large Telescope, on site at Cerro Armazones, Chile. (Courtesy: ESO/L Calçada)

By Tushna Commissariat

Although a site for the most ambitious project of the European Southern Observatory (ESO) – the European Extremely Large Telescope (E-ELT) – was picked in 2010, astronomers were not sure if the project would get the definite go-ahead. But yesterday, at a meeting at ESO’s headquarters in Garching, Germany, the ESO Council approved the construction of what is to be the largest optical/infrared telescope in the world.

The one remaining stumbling block is that four of ESO’s 12 member states – Belgium, Finland, Italy and the United Kingdom – have only provisionally voted in favour of the project. Construction will only begin when they have agreed and 90% of the €1.083bn funding required has been secured. ESO says that the facility should then be able to start operations early within the next decade.

The 39.3 m diameter E-ELT will be about 80 m high, with a monstrous dome almost the size of a football stadium and a base diameter of about 100 m. It is planned to be tens of times more sensitive than any current ground-based telescope of its kind and will be built in Cerro Armazones in northern Chile, close to ESO’s Paranal Observatory. ESO hopes that most of the funding, as well as the initial large-scale industrial contracts, will be approved by next year. Some contracts for specific parts that require a detailed design study have, however, already been signed.

With the E-ELT, astronomers will be primed to discover Earth-like extrasolar planets and to study the distribution of dark matter and dark energy, which are thought to make up most of our universe. John Womersley, chief executive of the UK’s Science and Technology Facilities Council, says that its commitment to the E-ELT “reflects its high priority in our science strategy, the world-leading position of the UK astronomy community, and the potential returns to UK industry”.