Pioneering solar telescope begins operation in China to advance high precision measurements

Pioneering solar telescope begins operation in China to advance high precision measurements
by Riko Seibo
Tokyo, Japan (SPX) Oct 24, 2025

China has begun operating the world's first solar magnetic-field telescope that utilizes the mid-infrared wavelength range, representing a notable advancement in solar magnetic field research. Named the Accurate Infrared Magnetic Field Measurements of the Sun (AIMS), the instrument is located in Lenghu township, Qinghai province, at an elevation near 4,000 meters. The AIMS project addresses a longstanding challenge in the field by enabling direct, rather than indirect, measurements of solar magnetic fields, a breakthrough highlighted by the scientists responsible for its construction.

Deng Yuanyong, lead researcher at the National Astronomical Observatories of the Chinese Academy of Sciences, explained, "The sun, being the only star we can observe with high precision, has a magnetic field that acts as the energy switch driving intense solar activities such as flares and coronal mass ejections. Yet, more than half the sun's overall magnetic field manifestations are relatively weak, with strengths of only a few dozen gauss." Gauss is the standard unit for measuring magnetic field strength.

He noted that while China's traditional measurement methods meet international norms with 100-gauss precision, they have not sufficed for contemporary solar physics. Evaluations reveal that AIMS reaches precision better than 10 gauss, an unprecedented capability globally. "It is the world's first solar magnetic-field telescope operating in the mid-infrared wavelength range and China's first astronomical instrument to work in this band," Deng stated.

All major components of the telescope are produced domestically, bolstering the country's proficiency in independent technological innovation. The off-axis optical design of AIMS reduces interference from background noise in the mid-infrared, and a combination of cooling and filtering technologies further enhances its measurement accuracy.

Additionally, the infrared-separating spectrograph built into the system enables detailed spectroscopic imaging of the solar atmosphere. The team developed a novel polarization modulation technique and constructed a polarization-aberration-free optical assembly using five mirrors to mitigate instrumental errors.

AIMS is engineered for near year-round operation, factors like weather permitting, with a target of 250 active days each year. Data from the telescope is expected to inform solar physics and improve space weather forecasting. Deng expressed enthusiasm for fostering collaborative efforts with leading international research groups in the field.