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The ELT (Extremely Large Telescope) project aims to provide European astronomers with the largest optical-infrared telescope in the world. With a diameter of 40m and incorporating a large deformable mirror, the ELT is expected to tackle the biggest scientific challenges of our time, and aim for a number of notable firsts, including tracking down Earth-like planets around other stars in the "habitable zones" where life could exist. It will also perform "stellar archaeology" in nearby galaxies, as well as make fundamental contributions to cosmology by measuring the properties of the first stars and galaxies and probing the nature of dark matter and dark energy.

The telescope 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 1000 hexagonal segments.

The telescope will have several science instruments deployed in several stages as ELT develops. UK institutes are involved in several of these concepts, including leading one (HARMONI) that is expected to be delivered as ELT starts operation. It will be possible to switch from one instrument to another within minutes. The telescope and dome will also be able to change positions on the sky and start a new observation in a very short time. The ability to observe from visible to mid-infrared wavelengths will allow scientists to exploit the telescope’s size to the fullest advantage. ESO is expected to approve the start of the construction phase of this 1Bn Euro project at the end of 2011. The UK is expected to play a leading role in the development of instrumentation, definition of the science programme and via industrial return through contracts. Operation is expected around the mid-2020s.

UK Involvement

Durham University

STFC UK Astronomy Technology Centre

University of Oxford
STFC Rutherford Appleton Laboratory

Last updated: 13 September 2019


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