The European Southern Observatory’s Extremely Large Telescope (ELT), currently under construction on Cerro Armazones mountain in Chile’s Atacama Desert, is making significant progress. The telescope, expected to reach its “first light” by 2028, will be the world’s largest visible- and infrared-light telescope.
Key milestones include the completion of the dome’s structure, central structure, and base for the primary mirror. One of five mirrors that work together to observe the cosmos, the M1 mirror measures 39 meters (128 feet) across and weighs 200 tons. Its white lattice structure will allow it to move smoothly during observations.
Construction updates are available through live webcams, drone footage, and photographs on-site. The telescope’s secondary mirror (M2), estimated to be completed in 2025, will reflect light collected by M1 to the tertiary mirror (M3). The dome and telescope structure are expected to be completed by 2026.
The ELT is expected to observe terrestrial exoplanets and their atmospheres, as well as measure the expansion of the universe. With a planned development timeline spanning two decades, the telescope will be one of the European Southern Observatory’s main flagships.
Source: https://www.space.com/the-universe/a-giant-rising-in-the-desert-worlds-largest-telescope-comes-together-photo