报告摘要：On Earth’s surface, there are only a handful of high-quality astronomical sites that meet the requirements for very large next-generation facilities. In the context of scientific opportunities in time-domain astronomy, a good site on the Tibetan Plateau will bridge the longitudinal gap between the known best sites1,2(all in the Western Hemisphere). The Tibetan Plateau is the highest plateau on Earth, with an average elevation of over 4,000 metres, and thus potentially provides very good opportunities for astronomy and particle astrophysics3–5. Here we report the results of three years of monitoring of testing an area at a local summit on Saishiteng Mountain near Lenghu Town in Qinghai Province. The altitudes of the potential locations are between 4,200 and 4,500 metres. An area of over 100,000 square kilometres surrounding Lenghu Town has a lower altitude of below 3,000 metres, with an extremely arid climate and unusually clear local sky (day and night)6. Of the nights at the site, 70 per cent have clear, photometric conditions, with a median seeing of 0.75 arcseconds. The median night temperature variation is only 2.4 degrees Celsius, indicating very stable local surface air. The precipitable water vapour is lower than 2 millimetres for 55 per cent of the night. As of the beginning of 2022, the infrastructure suitable for a new giant observatory is almost ready, and a total number of 9 observing projects has begun their construction. As a strategic resource for future developments in Astronomy in China, dark night sky preservation in the surrounding area of Lenghu site is now under discussion.

主讲人简介：Licai Deng got his PhD in 1994 from SISSA (Schuola Internazionale Studi Superiori Avanzadi), Italy, MS from Purple Mountain Observatory (Stellar physics) in 1987, and BS from Sichuan University (Theoretical physics) in 1984. He has been working on observational and theoretical stellar astrophysics since joining Beijing Astronomical Observatory (BAO, the predecessor of NAOC) of CAS in 1997. He has been the PI of the research group since 1999. He has been working primarily on Stellar structure and evolution, stellar pulsation and oscillations, stellar populations in clusters and galaxies, both observationally and theoretically. Starting from 2009, he has been involved in developing a node for the global campaign of stellar oscillations, otherwise called Stellar Observations Network Group (SONG), and its daughter project 50BiN. In last more than 10 years, he has been working on site qualification for SONG/50BiN in Delingha Radio observing site, building up the facilities, and running the science programs. In 2018, he led a site testing project at Lenghu, independent of general site selection for 12m LOT proposal, which turned out to be very successful.