China's 110-Meter Qitai Radio Telescope Enters Final Phase, Set to Be World's Largest Steerable Dish

A 6,000-Tonne Dish Takes Shape Above the Tianshan Foothills

The Qitai radio telescope (QTT), built by the Xinjiang Astronomical Observatory under the Chinese Academy of Sciences, sits in Qitai County roughly 260 kilometers from the regional capital Urumqi, at an average elevation of about 1,760 meters. The site was chosen for its exceptional radio environment: with no other large radio telescope within 2,500 kilometers, the surrounding mountains shield the facility from the interference that plagues observatories near cities. Remote desert locations have become a hallmark of Chinese astronomy infrastructure, following the same logic that placed the 500-meter FAST dish in a karst depression in Guizhou.

State broadcaster CGTN reported that the three-layer antenna mount was successfully assembled on August 18, moving the project into its final construction phase. Global Times, citing CCTV News, said the main structure is scheduled for completion in 2027, with the entire facility expected to be finished and put into operation in 2028. Construction of the telescope began on September 21, 2022, placing the project roughly four years into a six-year build that has required heavy machinery, specialized steel fabrication and year-round work at altitude.

Engineering a Fully Steerable Giant

The QTT's defining feature is its ability to point anywhere across the sky. Unlike a fixed reflector such as FAST, a fully steerable dish can track objects as the Earth rotates, a requirement for observing everything from spacecraft to fast-moving celestial sources. At 110 meters in diameter and 6,000 tonnes, the QTT is designed to operate across a frequency range of 150 megahertz to 115 gigahertz, according to the Xinjiang Astronomical Observatory. That span is unusually wide, letting a single instrument cover low-frequency pulsar work and high-frequency molecular spectroscopy alike.

Chinese media have emphasized the telescope's precision. Global Times described the project as the world's highest-precision 100-meter-class radio telescope, a claim tied to the surface accuracy needed to observe at the upper end of its frequency range, where short wavelengths demand near-perfect reflector geometry. Engineers must also contend with wind loading, thermal expansion across a dish the size of a football field, and the tracking motors required to swing the structure smoothly against gravity. Those challenges are why fully steerable dishes above 100 meters remain rare: the United States' Green Bank Telescope in West Virginia and Germany's Effelsberg telescope both measure 100 meters, and both are decades old. The completion of the QTT's three-tier antenna mount, the structural heart of the design, clears the way for installation of the reflector surface panels and the receiver systems that will ride above the dish.

Filling the Gaps Around FAST

The QTT is best understood as the mobile partner to FAST, the 500-meter fixed dish that has made China a center of pulsar research since it began full operations in 2020. FAST's sensitivity is unmatched, but its reflector can only tilt so far, limiting which parts of the sky it can observe at any given moment. A fully steerable 110-meter dish adds flexibility that a fixed bowl cannot provide, and it can be pointed at a target within minutes rather than waiting for the sky to rotate into view.

Project materials published by the Chinese Academy of Sciences indicate the QTT will be able to cover more than 75 percent of the sky down to a declination of about minus 40 degrees, including a large fraction of the plane of the Milky Way. That coverage matters for pulsar timing arrays, which use the precise arrival times of radio pulses to search for the ripples in spacetime predicted by gravitational waves. China's Pulsar Timing Array collaboration has already published preliminary gravitational-wave background results using FAST; the QTT would give the effort a second, steerable workhorse and extend observations into frequency bands where FAST is less effective. The same sensitivity profile supports studies of masers, interstellar magnetic fields and the chemistry of star-forming clouds, while the dish's agility makes it a strong platform for catching fast-changing events such as gamma-ray burst afterglows and the flares of magnetars, targets that fixed-aperture telescopes can struggle to reach in time.

A New Asset for Deep-Space Tracking

Fully steerable dishes of this class double as deep-space tracking stations, and the QTT's location is well suited to that role. The United States operates three 70-meter antennas in its Deep Space Network to communicate with missions across the solar system, while Japan's Usuda 64-meter antenna in Nagano prefecture has supported deep-space probes since the 1980s. China has been expanding its own network, with stations in Jiamusi and Kashi, to support the lunar Chang'e missions, the Tianwen Mars program and upcoming asteroid-sampling flights.

A 110-meter steerable dish in Xinjiang would add significant tracking and telemetry capacity, and crucially, a long-baseline node for very long baseline interferometry (VLBI). By linking telescopes thousands of kilometers apart, VLBI turns them into a virtual dish the size of a continent. Chinese researchers have used VLBI to refine the positioning of lunar and Mars probes; a facility as large as the QTT would sharpen those measurements and strengthen China's hand in international VLBI collaborations, where observation time on the largest dishes is a form of scientific currency.

Japan and the Asia-Pacific Radio Astronomy Race

For Japan, the QTT changes the competitive geometry of East Asian radio astronomy. Japan's National Astronomical Observatory operates the 45-meter Nobeyama telescope in Nagano, which was the world's largest millimeter-wave dish when it opened in 1982, and the JAXA Usuda station remains a key deep-space asset. Japanese and Chinese stations already cooperate through the East Asian VLBI Network, which links telescopes in Japan, China and South Korea, including Japan's four 20-meter VERA antennas, South Korea's KVN array and China's 65-meter Tianma dish near Shanghai. The QTT would become by far the largest single dish in that network.

The contrast in trajectories is striking. Japan's major single-dish facilities are aging, and its newest investments have gone into international projects such as ALMA in Chile. China, by contrast, has been on a sustained big-science build-out, adding FAST, the QTT and a fleet of optical and space-based instruments within a single decade. The result is a region where leadership in radio astronomy is quietly shifting, even as the infrastructure for cooperation remains in place. For Japanese researchers, the QTT represents both a competitive challenge and a potential observing partner: the dish's size will make it a sought-after resource, and East Asian collaboration could give Japanese scientists access to capabilities no longer available at home.

What to Watch For

The immediate milestones are structural: completion of the main structure in 2027, followed by commissioning and first light before full operations in 2028. Beyond the build itself, watch whether the QTT joins VLBI campaigns with Japanese and Korean partners, whether it is assigned deep-space tracking duties for the next Chang'e and Tianwen missions, and whether its early science program targets the pulsar timing work where FAST has already delivered results.

For readers across the Asia-Pacific, the telescope is a reminder that the region's space race is no longer only about rockets and satellites. The quiet infrastructure of science, radio dishes and timing arrays, is being built too, and Xinjiang's mountains will soon host the largest steerable ear on Earth. How Japan and its partners respond, through new facilities or deeper collaboration, will shape the region's astronomical agenda for decades.

By Kenji Tanaka, Staff Writer

This article was produced with AI-assisted research and editorial support. Sources: CGTN, Global Times, Chinese Academy of Sciences, Xinjiang Astronomical Observatory.