Uploaded July 2026 | Updated September 2026, 2 weeks ago
The ELT’s dome, still partially uncovered and showing its steel skeleton in the beginning of this video, has mostly finished receiving its layer of protective insulated cladding, designed to protect the telescope and its instruments from the harsh desert environment, including very rare but heavy rains. When the massive doors were installed the dome reached its highest point of 80 meters in April of 2025, with a topping-out ceremony that featured the raising of ESO and Chile flags on top of the dome. Later in the year, the dome’s doors were moved for the first time.
Meanwhile, inside the dome, the main structure of the ELT, that will hold its mirrors and instruments, is progressing fast. This structure, currently weighing around 3500 tonnes, was recently rotated around its vertical axis for the first time.
This video doesn’t capture the advances carried out off-site, such as testing the ELT’s deformable mirror, key to correct atmospheric turbulence and obtain sharp images. The construction of MICADO and METIS, the first instruments to be installed at the ELT, is also progressing well. An agreement for MOSAIC, another ELT instrument, was signed in the end of 2025. With the telescope components and instruments coming together, the ELT is well on its way to start observing the cosmos later this decade.
More information and download options: eso.org/public/videos/potw2629a
Credit:
ESO.
Music: Jon Kennedy – Funk Construction
Footage and photos: ESO, Apical, J. Porte/Chepox, A. Ubilla/Chepox, G. Vecchia/ESO
Acknowledgements: Cimolai
The ELT’s dome, still partially uncovered and showing its steel skeleton in the beginning of this video, has mostly finished receiving its layer of protective insulated cladding, designed to protect the telescope and its instruments from the harsh desert environment, including very rare but heavy rains. When the massive doors were installed the dome reached its highest point of 80 meters in April of 2025, with a topping-out ceremony that featured the raising of ESO and Chile flags on top of the dome. Later in the year, the dome’s doors were moved for the first time.
Meanwhile, inside the dome, the main structure of the ELT, that will hold its mirrors and instruments, is progressing fast. This structure, currently weighing around 3500 tonnes, was recently rotated around its vertical axis for the first time.
This video doesn’t capture the advances carried out off-site, such as testing the ELT’s deformable mirror, key to correct atmospheric turbulence and obtain sharp images. The construction of MICADO and METIS, the first instruments to be installed at the ELT, is also progressing well. An agreement for MOSAIC, another ELT instrument, was signed in the end of 2025. With the telescope components and instruments coming together, the ELT is well on its way to start observing the cosmos later this decade.
More information and download options: eso.org/public/videos/potw2629a
Credit:
ESO.
Music: Jon Kennedy – Funk Construction
Footage and photos: ESO, Apical, J. Porte/Chepox, A. Ubilla/Chepox, G. Vecchia/ESO
Acknowledgements: Cimolai
