The Extremely Large Telescope (artist’s rendering)

This new artist’s impression shows the future Extremely Large Telescope (ELT), which is currently being planned by ESO. This revolutionary new ground-based telescope will be the largest optical/near-infrared telescope ever conceived, and will serve as “the world’s biggest eye on the sky”.

The present concept is for a telescope with a mirror 39 metres in diameter, able to capture images of the sky about a tenth the size of the full Moon. The telescope will contain five mirrors, a novel configuration that results in exceptional image quality. The largest (primary) mirror will consist of almost 800 segments, each 1.4 metres wide but only 50 mm thick. The optical system’s design also calls for an immense secondary mirror measuring 4.2 metres in diameter, which is almost as large as the biggest primary mirrors used in today’s telescopes.

With the start of operations planned early in the next decade, the ELT will tackle the biggest scientific challenges of our time. The massive telescope will take aim at a number of notable astronomical firsts, including tracking down Earth-like planets orbiting other stars in the “habitable zones” where life could exist — one of the hottest topics of modern observational astronomy. It will also perform “stellar archaeology” in nearby galaxies and make fundamental contributions to cosmology by measuring the properties of the first stars and galaxies. In addition, the ELT will probe the nature of dark matter and dark energy. During these scientific quests, astronomers eagerly anticipate some unexpected twists — new and unforeseeable questions will surely arise from discoveries made with the ELT.

The design for the ELT shown here was published in 2009 and is preliminary.

Other ELT images are also available on this link.