This file photo taken on April 23, 2017 shows the Ngari Observatory of the National Astronomical Observatories (NAO) in Ngari Prefecture, southwest China's Tibet Autonomous Region.

You Xianlong (L) and his colleague Tang Peng test a telescope at the Ngari Observatory in Ngari Prefecture, southwest China's Tibet Autonomous Region, May 23, 2023.

This photo taken on May 24, 2023 shows the Ngari Observatory at sunset in Ngari Prefecture, southwest China's Tibet Autonomous Region.

You Xianlong heads for his office at the Ngari Observatory in Ngari Prefecture, southwest China's Tibet Autonomous Region, May 24, 2023.

You Xianlong (L) and his colleague Tang Peng test a telescope at the Ngari Observatory in Ngari Prefecture, southwest China's Tibet Autonomous Region, May 23, 2023.

You Xianlong gazes into the night sky at the Ngari Observatory in Ngari Prefecture, southwest China's Tibet Autonomous Region, May 23, 2023.

You Xianlong tests a telescope at the Ngari Observatory in Ngari Prefecture, southwest China's Tibet Autonomous Region, May 24, 2023.

You Xianlong walks out a telescope dome at the Ngari Observatory in Ngari Prefecture, southwest China's Tibet Autonomous Region, May 24, 2023.

This photo taken on May 24, 2023 shows the Ngari Observatory at night in Ngari Prefecture, southwest China's Tibet Autonomous Region.

You Xianlong talks with his family over the mobile phone at the Ngari Observatory in Ngari Prefecture, southwest China's Tibet Autonomous Region, May 24, 2023.