Preparing a Revolution

Artist impression of the ELTAstronomy is experiencing a golden era. The past decade alone has brought amazing discoveries that have excited people from all walks of life, from the first planets orbiting other stars to the accelerating Universe, dominated by the still-enigmatic dark matter and dark energy.

Europe is at the forefront of all areas of contemporary astronomy, thanks in particular to the flagship ground-based facilities operated by ESO, the pre-eminent intergovernmental science and technology organisation in astronomy. The challenge is to consolidate and strengthen this position for the future. This will be achieved with a revolutionary new ground-based telescope concept, the Extremely Large Telescope (ELT), with a performance that is orders of magnitude better than currently existing facilities. Such a telescope may, eventually, revolutionise our perception of the Universe, much as Galileo's telescope did, 400 years ago.

The green light for the construction of the 39-metre Extremely Large Telescope was given by the ESO Council in late 2014, with a planned construction period of about a decade.

The telescope's "eye" will be almost half the length of a soccer pitch in diameter and will gather 15 times more light than the largest optical telescopes operating today. The telescope has an innovative five-mirror design that includes advanced adaptive optics to correct for the turbulent atmosphere, giving exceptional image quality. The main mirror will be made up from almost 800 hexagonal segments.