The world’s largest telescope takes shape in Chile – Space & Astronomy

Thanks to a consortium of Italian companies, the world’s largest optical infrared telescope, the European Southern Observatory’s (ESO) Extremely Large Telescope (ELT), is being built at an altitude of 3,000 meters in the Chilean desert. With strong scientific and technological contribution from our country.

This was explained by the experts gathered at the National Institute of Astrophysics (INAF) to celebrate the 60th anniversary of the founding of the European Meteorological Society and 40 years of Italian participation in this large international organization, which today includes 16 member states and the most advanced astronomical observatory in existence.

“ESO represents the best organization in the world for the design and operation of ground-based telescopes: among the member states, Italy is the fourth-largest contributor in terms of industrial return,” underscores Adriano Fontana, Head of the National Qualification Section. From the development of optical and infrared astronomy.

“Italy is at the forefront not only in developing new instruments for the Very Large Telescope (of the nine instruments under construction, three are Italian-led, while the other three see important participation for our country), but also in creating the structure and instruments for the Very Large Telescope of the future.”

The ELT, which will see first light in 2028, will be similar in size to the Colosseum: it will have a base with an outer diameter of 100 meters, a height of 80 meters, and to follow the stars in the sky it will be able to move its 3,500-ton mirrors with an accuracy of a few nanometers. In terms of sensitivity and image sharpness, Elt will be six times more powerful than the James Webb Space Telescope, explains Michelle Cirasulo of ESO.

It will have a primary mirror (called M1) measuring 39 meters in diameter, consisting of 798 segments of 1.4 meters each which will be polished differently from each other. The system will also be equipped with adaptive optics to correct light distortions caused by the Earth’s atmosphere. The core component, the 2.5-meter-high M4 mirror, will be built by Italian consortium AdOptica. “At just 1.9 mm thick, it will have 5,300 actuators that will change shape a thousand times per second to increase sensitivity and accuracy,” adds Cirasuolo.

The dome and the main structure of the telescope where the mirrors will be placed are made by the Federation of Italian Industries, Cimolai and Astaldi: the first part of the outer ring, 12 meters high, is currently being worked on. Of the six science tools under development, two are Italian-led, Morpheo and Andis, while the other two (Mikado and Mosaic) are seeing strong Italian participation.

Many of the technological and scientific challenges this new instrument poses to ESO, which in these 60 years has been “the second home for entire generations of astronomers and technologists,” Fontana notes. Its infrastructures serve a community of 22,000 astronomers from more than 130 countries and about eighty Italians work there. The prospects for the future are positive, as noted by the President of the Institute, Marco Tavani: “I am glad that the Pnrr Infrastructure Program has also been taken up and focused in some way on Eso’s activities, which we also have support to grow and strengthen our participation.”