The Extremely Large Telescope (ELT), set to become the world's largest visible- and infrared-light telescope, is taking shape at its construction site atop Cerro Armazones in Chile's Atacama Desert. Managed by the European Southern Observatory (ESO), the ELT is expected to revolutionize astronomical research upon its completion, targeted for 2028.

The telescope's dome, which spans an impressive 305 feet in diameter and rises 263 feet in height, has made significant progress. The outer shell is still under construction, while the dome frame has been completed. The dome will be shielded from the region’s harsh weather conditions using aluminum plates, ensuring the telescope's functionality in fluctuating temperatures. Large sliding doors will allow for nighttime operations while protecting the telescope during the day.

Inside the dome, the construction of the polygonal base is nearly complete. This base will support the ELT's primary mirror (M1), which is poised to become the largest ever made for an optical telescope. The mirror will consist of 798 hexagonal glass ceramic segments, each 5 feet across and 2 inches thick. The secondary mirror (M2), with a diameter of 14 feet, is also under development and will be completed later this year. Both mirrors will be supported by a central structure called the "spider," which features six arching arms for precise positioning.

The ELT's altitude structure, which stands 164 feet tall, will support all five mirrors and allow for smooth rotation to observe various parts of the sky. Once operational, the ELT will provide groundbreaking capabilities for observing distant exoplanets and celestial phenomena, greatly advancing our understanding of the universe's expansion and the potential for life beyond Earth.