The European Extremely Large Telescope (E-ELT) is a project to build a telescope with a mirror measuring 39.3 meter. The effective surface will be about 1000 m2 (almost a quarter of a soccer field). The telescope has been design bij the European Southern Observatory (ESO). ESO is an international organisation that represents 14 (if Brasil and Poland ratify it will grow to 16) nations that want to do world leading astronomical research.

ESO choose to build the E-ELT after a feasibility study showed that the Overwhelmingly Large Telescope with a diameter of 100 meter would cost more than 1.5 billion euro and be too complex to be built.


The Telescope

Present techniques for mirror manufacturing allow only for a single mirror of about 8 meter diameter. For the E-ELT a segmented main mirror will therefore be used, like is done for the Keck telescopes.The 39.3 meter main mirror will consist of about 800 hexagon shaped mirror elements. The dome which will protect the telescope willhave a diameter of about 100m and a hight of roughly 80 meter.

Science and the E-ELT

The aim of the E-ELT is to study the Universe in even higher detail than presently is possible with groundbased and space-based telescopes. Aided by adaptive optics that will cancel out the disturbances of our atmosphere, the E-ELT will be able to make images 20 times sharper than the Hubble Space Telescope, and 15 times fainter than what is possible with the present largest telescopes on Earth.

With the start of operations planned for early in the next decade, the E-ELT will 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 — one of the Holy Grails of modern observational astronomy. 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. On top of this astronomers are also planning for the unexpected — new and unforeseeable questions will surely arise from the new discoveries made with the E-ELT.

An extended description of the scientific background of this telescope can be found in "An Expanded View of the Universe – Science with the European Extremely Large Telescope"

Building an E-ELT

Selecting the site:

An extraordinary telescope calls for an exceptional site. Much care is thus taken to ensure that the future home of the E-ELT will be the most adequate possible. This generally means a high, dry site, so as to have as little hindrance to the observations. The E-ELT Site Selection Advisory Committee has been investigating in great detail several possible sites, in Argentina, in Chile, in Morocco, and in Spain. The technical report concludes that Cerro Armazones, near Paranal, stands out as the clearly preferred site, because it has the best balance of sky quality across all aspects and it can be operated in an integrated fashion with the existing ESO Paranal Observatory. Cerro Armazones is a mountain at an altitude of 3060 metres in the central part of Chiles Atacama Desert, some 130 kilometres south of the town of Antofagasta and about 20 kilometres from Cerro Paranal, home of ESOs Very Large Telescopes.

Building the Telescope:

It is expected that it will take about 10 years to build the telescope, which implies that around 2024 the first observations can be made. This is an enormous challange, because it is like building a rotatable football stadium at the top of a 3000 meter heigh mountain in the middle of a desert. And we should not forget that in the end there should be a machine that is able to see so sharp, that it can see a pinpong ball at the the international space station.

For Industry that is interested to participate in the E-ELT project please consult ESO's Industry Procurement page.

More information about this project can be found at the E-ELT website of ESO.

Click here for more information about the instrumentation


A telescope without instrumentation is like a camera without a CCD (or film in the old days). The telescope focusses the light, but it is the instruments who will make sure that the light is caught and can be studied by the astronomers. For the E-ELT 9 instrument studies have been performed, in which NOVA was directly involved in 4 of them. 


Instrument studies where NOVA is involved


Planet Imager, Spectrograph and Imaging Polarimeter with Extreme Adaptive Optics, will do observations between 0.6 and 1.65 µm.



Mid-infrared Imager and Spectrograph, will do observations between 2.9 and 14 µm.



Imager and Slit Spectrograph, will do observations between 0.8 and 2.5 µm.



Optical-NIR Fibre-based Multi Object Spectrograph, will do observations between 0.37 and 1.7 µm.

Other instrument studies


High Resolution, High Stability Visual Spectrograph, will do observations between 0.37 and 0.71 µm.



AO-assisted Multi-integral Field NIR Spectrometer, will do observations between 0.8 and 2.45 µm.



Single Field Integral-field Spectrograph, will do observations between 0.47 and 2.45 µm.   



Wide-Field Imager & Low-Medium Resolution Slit Spectrograph, will do observations between 0.37 and 1.6 µm.



Cross-dispersed Echelle Spectrograph, Long-slit Option, will do observations between 0.8 and 2.5 µm.

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