World’s largest solar telescope array almost complete

At the edge of the Tibetan Plateau, engineers are mounting the latest pieces of hardware on the world’s largest network of telescopes to study the Sun.

Construction of the Daocheng Solar Radio Telescope (DSRT), which consists of more than 300 dish-shaped antennas forming a circle more than 3 kilometers in circumference, is expected to be completed by the end of next month. Trial operations will begin in June. The 100 million yuan ($14 million) observatory will help researchers study solar flares and their impact on conditions around Earth.

“We are entering the golden age of solar astronomy because many major solar telescopes are online,” says Maria Kazachenko, a solar physicist at the University of Colorado at Boulder. These include NASA’s Parker Solar Probe, launched in 2018, and the European Space Agency’s Solar Orbiter, launched in 2020, both of which collect data while orbiting the star.

The Sun is expected to enter a very active phase over the next few years. The radiofrequency data collected by DSRT will complement those collected by telescopes working in other frequency bands. Over the past two years, China has launched at least four sun-watching satellites — including the space-based Advanced Solar Observatory in October — which study the star at ultraviolet and X-ray frequencies. China now has instruments capable of observing all levels of the Sun, from its surface to the outermost atmosphere,” says Hui Tian, ​​a solar physicist at Peking University in Beijing.

Observatories in China will also provide important data on solar activities that are not visible to telescopes in other time zones, says Ding Mingde, a solar physicist at Nanjing University. Solar research requires global collaboration, he adds.

Stellar explosions

Radio telescopes such as DSRT are useful for studying activities in the Sun’s upper atmosphere – the corona – such as solar flares and coronal mass ejections (CMEs). These are giant flares of hot plasma from the corona that occur when the twisted magnetic field of the Sun “breaks” and then reconnects. When high-energy particles released during a CME rush towards Earth, the resulting “space weather” can damage orbiting satellites and disrupt power grids on Earth.

In February, a relatively weak CME destroyed 40 Starlink communications satellites launched by SpaceX, a California aerospace company. “With an increasing number of satellites in space, there is a growing need to better predict space weather,” Ding says.

Kazachenko says space weather forecasting remains a struggle. DSRT has a wide field of view, at least 36 times larger than the Sun’s disk, which will allow the telescope to track the development of CMEs and observe how high-energy particles propagate through space, says Jingye. Yan, the chief DSRT engineer at the National Center for Space Science, part of the Chinese Academy of Sciences, in Beijing. “With this information, we may be able to predict if and when coronal mass ejections will reach Earth,” Yan says.

DSRT’s 313 antennas will allow it to achieve high sensitivity for better space weather forecasting. The large array could potentially capture weaker signals from high-energy particles that might be missed by arrays observing in the same frequency range – 150 megahertz to 450 megahertz – with fewer antennas, such as the Nançay radioheliograph in France, which has 47 branches, says Yan.

DSRT observational data will be made available to international researchers, Yan says. And China’s National Space Science Center, which oversees the operation of DSRT, plans to open the telescope at night for other types of observation, such as research on pulsars. China is also building a new optical telescope on the Sichuan Tibetan Plateau which is expected to be completed in 2026.

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