Extremely Large Telescope Receives Roof in Major Milestone

Construction on the Extremely Large Telescope (ELT) in Chile’s Atacama Desert reached a significant milestone with the completion of its roof. The European Southern Observatory’s (ESO) ambitious project, valued at $1.4 billion, aims to establish the world’s largest optical telescope. This remarkable facility will feature a primary segmented mirror measuring 128 feet (or 39 meters) in diameter, making it approximately four times larger than any current ground-based optical telescope.

Located at Cerro Armazones, the ELT is designed to revolutionize our understanding of the universe. With its advanced capabilities, the telescope is expected to collect more light and produce images that are 15 times sharper than those captured by the Hubble Space Telescope. This leap in technology promises to unlock new insights into astronomical phenomena, enhancing research and exploration.

In an event marking the structural completion of the telescope, crews celebrated the roofing ceremony on April 16, 2025. This traditional ceremony, known as Tijerales, is a Chilean custom that involves raising the roof and is often accompanied by festivities. Flags representing both the ESO and Chile adorned the scaffolding as a symbol of the collaboration and support behind this monumental project. The celebration included a barbeque for the crew and was livestreamed to ESO’s headquarters in Garching, Germany, allowing an international audience to join in the excitement.

The ELT’s construction reflects the growing commitment to advancing astronomical research and technology. With this latest achievement, the ESO is not only paving the way for groundbreaking discoveries but also fostering a sense of community among scientists and enthusiasts worldwide. As construction progresses, the ELT stands as a beacon of innovation in the field of astronomy, poised to enhance our exploration of the cosmos.

For more information on the Extremely Large Telescope and other major observatories in Chile, interested readers can visit the ESO’s official website.