Free Astronomy Magazine September-October 2023

4 SEPTEMBER-OCTOBER 2023 ASTRO PUBLISHING The Extremely Large Telescope is now half completed by ESO − Bárbara Ferreira T he European Southern Obser- vatory’s Extremely Large Tele- scope (ESO’s ELT) is a revolu- tionary ground-based telescope that will have a 39-metre main mirror and will be the largest telescope in the world for visible and infrared light: the world’s biggest eye on the sky. Construction of this technically complex project is advancing at a good pace, with the ELT now sur- passing the 50% complete mile- stone. The telescope is located atop Cerro Armazones in Chile’s Atacama Desert, where engineers and con- struction workers are currently as-