The European Southern Observatory (ESO) has announced that construction of the Extremely Large Telescope (ELT) has reached 60% completion. Eight years after work began, the dome frame protecting the 39-meter mirror of 798 segments has been completed and one of the massive flaps that open the telescope for nighttime observations has been installed.
The telescope, located at an altitude of 3050 meters in Chile, is designed for studies in the optical and infrared. The recently installed dome flap is an important milestone, but the second is still waiting to be installed. Progress is visible, although the pace is questionable: almost two years have passed since June 2023, when the readiness was 50%, and the increase is only 10%. ESO assures that the work is almost on schedule.
The telescope’s “first light” was originally scheduled for 2025, but pandemic and supply disruptions pushed the dates back first to 2027 and then to 2029. If there are no new delays, ELT will begin observations before the end of the decade.
