China Found a New World-Class Observatory Site
This place in western China is excellent for building an observatory and will fill a gap in the field of astronomical observation.
In a paper recently published in Nature, Chinese astronomers reported their monitoring data at a peak of a mountain in Lenghu town in Qinghai province. The data shows that this place is comparable to the best astronomical observing sites in the world today. This is not only a big discovery for Chinese scientists but also good news for the astronomy academia.
For astronomers, observing sites are greatly important. To study the universe, astronomers need to capture the faint light from distant celestial bodies. The observing site must be far away from light pollution, and the smaller the atmospheric disturbance, the better. At the same time, there must be enough sunny days. These requirements are very strict and there are only a few places on Earth meeting them.
Like other observatories, this newly discovered site is in a high-altitude area, the Tibetan Plateau. It is the world’s highest and largest plateau above sea level, with an average elevation of more than 4,000 meters. Apart from this, it is sparsely populated and dry with little rain. All of these are exactly what an observatory needs.
Astronomers have always thought Tibetan Plateau is a good place to build telescopes. But because of the harsh environment and the late development of Chinese astronomy, the existing observatories there are not good enough for building today’s most advanced telescopes. Some of them are threatened by light pollution in nearby towns, while others are too difficult to reach. In 2016, China proposed a national plan to build a 12-meters telescope. Chinese astronomers need to find a good foothold for it.
The appearance of Lenghu broke this situation. After overcoming many difficulties in the plateau, A team from China proved that Lenghu is a great place for astronomers with three years of monitoring. “In summary, this is a world-class astronomical observing site.” Deng Licai, the leader of this team from the National Astronomical Observatories of China, said during an interview with a Chinese media.
So how does Lenghu compare to the other world’s top observatories? Astronomers mainly use three characteristics to evaluate a site: sky brightness, seeing, and the number of sunny days. The darker the sky, the more celestial bodies can be seen. Seeing refers to the blur of the image of a celestial object due to irregular airflows in the atmosphere. That is also the reason why stars twinkle. The smaller the seeing, the smaller celestial bodies can be seen. And The number of sunny days determines how many days the telescope can work.
In the paper, the author compares Lenghu with the three best observatories today: Mauna Kea in Hawaii, Cerro Paranal in Chile, and La Palma in the Canary Islands of Spain. According to the monitoring data, Lenghu has the best sky brightness and the seeing while the number of sunny days is slightly lower than Mauna Kea and La Palma.
Although Lenghu does not surpass the existing sites in all aspects, one thing makes it unique: the location. Hawaii, Chile, and the Canary Islands are all located in the western hemisphere. This means that if some transient events occur in the night sky above the eastern hemisphere, these powerful telescopes can only wait for the earth to rotate and point them to the area of the sky where the event occurs. Lenghu is in the eastern hemisphere. When the western hemisphere is in daylight, the telescopes in Lenghu can observe.
Astronomers also proposed to unite telescopes of various regions to achieve an observation like a relay. Specifically, when the telescope of one country is in the daytime, the telescope of another country just ushered in the night, so that it can continue to observe a certain target. Through this method, scientists can obtain long-term continuous data. Lenghu is also an important role in this sense. It will make up the gap in time for astronomers to monitor the objects in the universe.
The discovery of Lenghu is an opportunity for the development of Chinese astronomy and a valuable resource for all astronomy researchers in the world. The Chinese Academy of Sciences stated that it will work with the local government to promote the construction of international telescope projects in Lenghu and strive to build Lenghu into an important base for world astronomy research.