The dome of the world’s largest telescope is completed in the Atacama Desert in Chile

Construction of the dome of the world’s largest visible light and infrared telescope, the Extraordinarily Giant Telescope (ELT), has progressed significantly. Located atop Cerro Armazones in Chile’s Atacama Desert, this state-of-the-art observatory is being developed under the direction of the European Southern Observatory (ESO). Scheduled for completion in 2028, the telescope is expected to provide unprecedented information about terrestrial exoplanets and the expansion of the universe. Currently, the telescope dome frame is already finished and the outer shell is still under construction.

Dome and outer shell construction

According According to a report by House.com, the dome has a diameter of 305 feet and a height of 263 feet, making it comparable in size to a football field. Aluminum plates will be installed to protect the telescope from the region’s extreme weather conditions, which include fluctuating temperatures. Large sliding doors in the dome will allow the telescope to operate at night while remaining securely closed during the day.

Telescope primary and secondary mirrors

The polygonal base inside the dome, which will house the telescope’s main mirror (M1), is nearing completion. The main mirror, which is expected to be the largest ever built for an optical telescope, will consist of 798 hexagonal glass-ceramic segments. Each segment measures approximately 5 feet wide and 2 inches thick. The secondary mirror (M2), with a diameter of 14 feet, is scheduled to be completed later this year. Both mirrors will be supported by a central structure known as a “spider,” distinguished by its six arched arms.

Sophisticated design for precision observations

The telescope’s altitude structure, 164 feet tall, is designed to support the five mirrors as it rotates to observe different parts of the sky. Once fully operational, the ELT is expected to redefine astronomical research by offering unparalleled observations of celestial phenomena, helping researchers unlock the mysteries of the universe.