China unveils plans for the largest optical telescope in Asia

A rendering of the final form of the Expanding Aperture Segmented Telescope (EAST).
A rendering of the final form of the Expanding Aperture Segmented Telescope (EAST). (Image credit: Peking University)

Peking University wants to build the largest optical telescope in Asia and close the gap in astronomy capabilities with the rest of the world.

The project aims to create an initial telescope with an aperture of 19.7 feet (6 meters) by 2024; the mirror will be expanded to 26.2 feet (8 m) by 2030. The project, which in English is called the Expanding Aperture Segmented Telescope (EAST), is being led by Peking University.

The telescope "will greatly improve China's observation capabilities in optical astronomy," according to a Peking University statement.

Related: The 10 biggest telescopes on Earth

The EAST abbreviation is fitting since the facility would become the first world-class optical telescope in the eastern hemisphere. Today's leading facilities are in the Western Hemisphere at sites around Mauna Kea in Hawaii, Atacama in Chile, and the Canary Islands off the coast of northwest Africa. 

The EAST project's first phase envisions building a mirror made up of 18 hexagonal mirror segments, resembling the mirror for NASA's James Webb Space Telescope. The mirror would have a diameter of around 19.7 feet, again similar to that of JWST. 

But unlike the newest space telescope, which orbits 1 million miles (1.5 million kilometers) away from the Earth at the second sun-Earth Lagrange point, EAST would be built on Saishiteng Mountain near Lenghu Town in Qinghai Province on the Tibetan plateau, at an altitude of around 13,800 feet (4,200 m).

A schematic shows the two phases of the mirror of China's proposed Expanding Aperture Segmented Telescope (EAST).  (Image credit: Peking University)

The second phase would add a ring of 18 more hexagonal segments around the mirror, expanding it to a diameter greater than 26.2 feet by 2030. 

Peking University estimates the project will cost between 500-600 million yuan ($69-84 million). Qinghai News reported last month that work on the project is progressing in an orderly manner. 

Peking University notes that astronomy plays an important part in technology and social development, and that the 2020 Nobel Prize in Physics was awarded to scientists who discovered the black hole at the center of the Milky Way using powerful optical telescopes including the twin Keck telescopes atop Mauna Kea and the Very Large Telescope (VLT) in Chile's Atacama Desert. 

EAST would also be a great addition to China's broader growing astronomy capabilities. The country has built the world's largest single aperture radio telescope, FAST, and plans to launch a large space observatory known as Xuntian as soon as late 2023.

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Andrew Jones
Contributing Writer

Andrew is a freelance space journalist with a focus on reporting on China's rapidly growing space sector. He began writing for in 2019 and writes for SpaceNews, IEEE Spectrum, National Geographic, Sky & Telescope, New Scientist and others. Andrew first caught the space bug when, as a youngster, he saw Voyager images of other worlds in our solar system for the first time. Away from space, Andrew enjoys trail running in the forests of Finland. You can follow him on Twitter @AJ_FI.