Extremely Large Telescope (ELT)

The Extremely Large Telescope (ELT) will be the world's largest telescope seeing visible and infra-red wavelengths. It is currently under construction, and is due to be completed in 2024. The primary mirror is 40 metres in diameter, and will collect 100 million times more light than the human eye.  Although it is a ground-based telescope, it will be able to produce images 16 times sharper than the Hubble Space Telescope.

Artist's impression of the ELT
Credit: ESO

Some facts about the telescope:

  • Observatory location: Cerro Armazones, Atacama Desert, Chile
  • Height above sea level: 3,046 metres (9,993 ft)
  • Moving Mass: 3000 metric tonnes
  • Mirror diameter: 39.3 metres

The science goals of the ELT include the study of exoplanets, early galaxies, supermassive black holes, and star formation. The ELT is designed to make detailed observations of the first galaxies, and to follow their evolution through time. Scientists may be able to measure the acceleration of the Universe's expansion, which would be a huge advancement in our understanding of cosmology.

The telescope has five mirrors: three mirrors are curved, two mirrors are flat. The curved mirrors will provide excellent image quality over a wide angle. The flat mirrors will provide adaptive optics and image stabilisation.