The Construction Milestone of the World's Largest Telescope: Protective Shell Completed!
2025-01-19
Author: Jia
Introduction
In a groundbreaking development, the frame for the dome of the Extremely Large Telescope (ELT), the world's largest telescope designed for visible and infrared light, has reached an impressive milestone as its construction progresses on the Cerro Armazones mountain in Chile's Atacama Desert. This state-of-the-art facility is expected to capture its "first light" by 2028, promising to revolutionize our understanding of the universe.
Dome Frame and Outer Shell
Recently released images by the European Southern Observatory (ESO) depict the completed dome frame, while construction continues on the outer shell, designed to completely enclose this colossal telescope. To safeguard the telescope from the harsh conditions of the Atacama Desert, including its extreme temperature fluctuations, plates of aluminum will be meticulously added to the exterior frame.
Dimensions and Purpose
Measuring a staggering 305 feet (93 meters) in diameter—equivalent to the size of a football field—and standing at a towering 263 feet (80 meters), this dome will serve as the protective home for the ELT. This groundbreaking telescope aims to investigate the atmospheres of terrestrial exoplanets and provide insights into the dynamic expansion of the universe.
Construction Progress
Progress has been thoroughly documented, with recent photos showcasing cranes diligently installing aluminum cladding. A distinctive feature of the dome will be its large sliding doors, designed to remain closed during the day but open at night, allowing the ELT to effectively scan the celestial expanse.
Inside the Dome
Inside the dome, essential advancements have also been made, notably on the polygonal structure that will cradle the telescope’s monumental primary mirror (M1). This mirror will measure an astonishing 128 feet (39 meters) across. Complementing this will be a secondary mirror (M2), measuring 14 feet (4.25 meters) in diameter and expected to be finalized later this year. In total, the ELT will incorporate five mirrors, three of which will be smaller, significantly enhancing its observational capabilities.
Unique Design Features
A remarkable feature of the ELT’s design is the "spider" structure, aptly named for its unique shape with six extending arms. While this framework is largely complete, it awaits the installation of the segmented mirrors. The monumental M1 will be composed of 798 hexagonal segments made from glass ceramic—each about 5 feet (1.5 meters) across yet only 2 inches (5 centimeters) thick—marking it as the largest mirror ever constructed for an optical telescope once fully assembled.
Altitude Structure
Supporting the entire structure is a central tower positioned beneath the spider framework. This metal framework, known as the altitude structure, stands 164 feet (50 meters) high and is designed to support all five mirrors of the ELT while enabling rotation, which is crucial for tracking different celestial targets across the sky.
Future Prospects
As construction on the ELT continues, excitement builds for the advanced capabilities this telescope will bring to astronomical science. Its unprecedented design and technological innovations herald a new era of discovery, making it a focal point of global interest in the pursuit of knowledge about the cosmos. Stay tuned for more updates as we march toward the anticipated first light in just a few years!