Which is the largest telescope in the world

E-ELT - the largest eye of mankind

Many of the most powerful telescopes in the world are already at home in the dry and cloud-free Atacama Desert in Chile. Because the desert offers ideal conditions for astronomical observations. The European Southern Observatory ESO, headquartered in Garching near Munich, operates several observatories there: La Silla, the Very Large Telescope (VLT) and the Atacama Large Millimeter Array (ALMA).

The next gigantic telescope has been under construction since 2014 at a distance of 20 kilometers from the VLT. While the VLT consists of four individual telescopes, each eight meters in diameter, the “extremely large telescope”, the E-ELT, will have a main mirror 39 meters in diameter. This means that it can collect 15 times as much light as previous telescopes in the ten-meter class and 16 times smaller details than the Hubble space telescope.

In order for the telescope to be able to achieve this level of performance at all, some technical masterpieces are necessary: ​​The main mirror, for example, consists of 798 individual hexagonal mirrors that are movably mounted. They can be continuously adjusted so that the mirror shape corresponds to the optically ideal shape at any temperature and any inclination of the telescope.

On the way to the cameras, the light from the telescope is directed via another mirror, which can be deformed a thousand times per second with almost 6000 adjusting elements and thus compensates for the unrest in the air. Six “artificial stars”, which are projected 90 kilometers high into the atmosphere with lasers, help.

From the start of operations in 2024, the E-ELT will enable science to look at the universe in a completely new way. Only with this new telescope will it be possible, for example, to directly discover and observe Earth-like planets from other stars. In this way, it may be possible to find evidence of water, an atmosphere and even living conditions there.

Other important questions for the E-ELT concern the prehistory and the future of the universe or the role of black holes. New puzzles will certainly be raised with the new observation options. Of the approximately 2500 astrophysicists in Germany, around two thirds will work with data from the E-ELT. The E-ELT is the next long-term development step in ground-based optical astronomy.

The ESO currently has 15 member states that jointly support the new major project scientifically, technically and financially. As the largest ESO member, Germany contributes around 230 million euros to the construction costs of the E-ELT, which totaled 1104 million euros (2014 price basis). Important instruments of the E-ELT such as the MICADO camera are also funded by the Federal Ministry of Research from collaborative research.