ELT Foundation Work Started on Cerro Armazones

The digging of the foundations for the dome and telescope structure of ESO’s Extremely Large Telescope (ELT) has begun on Cerro Armazones — at an altitude of over 3000 metres in Chile’s Atacama Desert. The work is being carried out by the ACe Consortium, consisting of Astaldi and Cimolai. These dramatic pictures were taken to mark this event by ESO photo ambassador Gerhard Hüdepohl, who used a drone to gaze down on Cerro Armazones.

Dubbed ELT, this revolutionary new ground-based telescope concept will have a 39-metre main mirror and will be the largest optical/near-infrared telescope in the world: “the world’s biggest eye on the sky”. Construction is targeted for completion in time for first light in 2024.

Working at such a high altitude is not easy, but the rewards will be great; this site is high, dry, and removed from light pollution. It will provide truly excellent seeing conditions, allowing astronomers to probe the mysteries of the cosmos as never before.

The outline of the telescope’s main structure is clearly visible and, when completed, an 80-metre-high dome will cover this outline. The 55-metre diameter circular pit at the centre will eventually contain the foundation for the structures supporting the colossal 39-metre primary mirror that gives the ELT its name. The photo also clearly illustrates just how large the telescope will be; the various construction vehicles dotted around look small when compared to the imposing size of the ELT’s foundations, and the people scattered across the site are almost invisible.

Cerro Armazones is only 22 kilometres from ESO’s current flagship observatory, the Very Large Telescope (VLT) — close enough that each will be visible from the other, and driving between the two will take roughly 30 minutes. This allows the ELT to be close to the support buildings and infrastructure currently used for the VLT. Cerro Armazones was actually almost chosen as the site for the VLT, but Cerro Paranal was chosen instead. However, with construction now underway, Cerro Armazones will soon have a telescope of its very own.

Courtesy of European Southern Observatory