Blog

At over 2.5 miles, Lenghu “is known for its unusually clear skies,” said Licai Deng, a scientist at the Chinese Academy of Sciences and co-author of the new study. “At the same time, the Lengu region has a spectacular landscape similar to Mars.” Dan says the local government, which is keen to attract tourists with an interest in astronomy and geography, hired his team to survey the area and see if it would be a suitable location for the observatory.

Four main factors influence how suitable any location is for astronomical research. First, if it has a clear sky – this means no dense cloud formations and very little light pollution. The second is the stability of local air and weather conditions, as well as how the atmosphere will affect optical and infrared observations at night (even the tiniest particles in the air can interfere). Thirdly, whether the site is connected to the infrastructure (for example, to the power grid) and whether it can be accessed without too many problems. Finally, you need an area where the night sky is protected from human activity.

Highlands such as Lenhu are of great interest to astronomers because there is simply less atmosphere to look through when looking at objects in space. Researchers observed the Lenhu area for three years, measuring the darkness of the sky, weather, atmospheric conditions, and more. They found that for all four factors, the area scored no less than other potential sites explored on the Tibetan plateau. Researchers believe that in many ways it could be better than existing locations in Hawaii and Chile. Air temperatures are less variable and atmospheric conditions are more stable, and the sky is slightly clearer. The amount of water vapor in the air is also small, which is especially useful for infrared observations, which are important for cosmology. Three decades of weather data show that there is an average of 0.71 inches of rain per year. “In this context, Lenhu has the potential to host large properties,” says Deng.

Ultimately, Lenhu may be more immune to the effects of human activity than Hawaii or Chile. In 2017, the city adopted regulations to keep the sky dark, so light pollution should be kept to a minimum.

“The results reported for the Lenhu site are almost on par with those for Mauna Kea, which is widely considered to be one of the best in the world,” says Paul Hickson, an astronomer at the University of British Columbia in Vancouver who previously conducted ground tests on Dome A. in Antarctica. “One thing that’s particularly appealing about this place is the focus on controlling light pollution.”

In some ways, this new study is a confirmation of China’s current astronomy plans in the Lenghu region. These plans include a 2.5-meter survey telescope, construction of which began this year, a 1-meter solar infrared telescope, which will become part of an international group of eight telescopes, and two other telescopes at 1.8 meters and 0.8 meters. for planetology.

As Deng points out, Tsinghua University and the University of Arizona are working together to create a 6.5-meter telescope to work on the summit of Mount Saishiteng. There are also plans to place a 12-meter telescope. “It will be very crowded at the top of the mountain,” says Dan.

These tools will significantly advance China on the map when it comes to infrared and optical astronomy – on par with some of the “large” telescopes used in places like Chile. But they still pale in comparison to “extremely large” observatories under construction around the world, such as the 24.5-meter Giant Magellan Telescope in Chile, the Thirty-Meter Telescope in Hawaii, and the 39.3-meter Extra Large Telescope in Chile. It is expected that the science in which these instruments can evolve will usher in a new era of astronomy. If China is serious about creating a more ambitious astronomical program, it will have to catch up.

In that case, it is good that there is a Tibetan plateau here. “High, dry, isolated mountains are the best place for astronomy,” says Hickson. “There may well be other potential sites on the Tibetan plateau, perhaps even better ones, that have not yet been explored.”