China News Service, Beijing, July 30 (Reporter Sun Zifa) The National Astronomical Observatory of the Chinese Academy of Sciences announced on the 30th that relying on the self-developed equipment installed at the Kunlun Station in China's Antarctica, the Zhaohui research team of the Taiwanese company has measured and obtained an excellent night atmosphere for the first time. Seeing degree proves that the optical astronomical observation conditions in Dome A, where Kunlun Station is located, are better than any other known ground stations.
This important achievement by Chinese astronomers confirming that Antarctica Dome A is the best optical astronomical observatory site on the ground was published in the internationally renowned academic journal "Nature" late at night on July 29, Beijing time. Industry experts believe that the research results confirm that Kunlun Station has precious astronomical observatory resources and will lay a solid foundation for China to further develop Antarctic astronomy research.
Two redundant seeing telescopes and their 8-meter-tall towers at Kunlun Station in Antarctica (photo at the time of installation). (Photo courtesy of the National Astronomical Observatory of the Chinese Academy of Sciences)
Shang Zhaohui said that the seeing degree represents the degree of blurring caused by atmospheric jitter on the telescope's observation of the stars. Under the condition of good seeing (the smaller the value, the better), the jitter caused by atmospheric turbulence in observing stars is relatively small, so the star images in the photos are sharper and clearer, and the observation of faint celestial bodies is more efficient. In an observatory with excellent visibility, the observation capability of a small-aperture telescope is comparable to that of large telescopes elsewhere. Therefore, the site selection of the observatory, the seeing degree is one of the most important parameters.
The geographical and atmospheric conditions of the Antarctic Dome A, where the Kunlun Station is located, indicate that atmospheric turbulence is mainly in the near-surface boundary layer, and the free atmosphere above is very stable, and it is expected to have a good seeing. This latest result is the first time to use the measured data to quantitatively calculate and evaluate the seeing degree of Dome A, and further prove that the atmospheric boundary layer of Dome A is very low, which is conducive to future observatory construction and cost control. .
According to the National Astronomical Observatory of the Chinese Academy of Sciences, the research team of Shang Zhaohui independently developed the Kunlun Seeing Telescope KL-DIMM. In November 2018, he participated in the 35th Antarctic scientific expedition in China and went to Kunlun Station in the inland. In January 2019, the site was successfully installed and debugged immediately. Invest in observation, and realize unattended operation, long-term fully automatic operation through the winter, and obtain precious night sight measurement data.
Antarctic map showing ice domes A, C, F, as well as the South Pole, Zhongshan Station and Taishan Station. (Photo courtesy of Pang Xiaoping and Wang Shiyun, China Antarctic Surveying and Mapping Research Center, Wuhan University)
KL-DIMM data shows that the median value of free atmospheric seeing is only 0.31 arcsec, the best value is 0.13 arcsec, and at a height of 8 meters from the ground, there is 31% of the time to obtain free atmospheric seeing; At a height of 14 meters above the ground, free atmospheric seeing can be obtained nearly half of the time. In comparison, the median height of the boundary layer of Dome C, which is also in Antarctica, is 30 meters, which is more difficult to obtain free atmospheric seeing than Dome A. Astronomical observation requires extremely high imaging quality. At present, the best telescopes in the world are concentrated on excellent sites in Hawaii and northern Chile, and the seeing is generally 0.6-0.8 arcseconds. The astronomical observation conditions of Dome A are significantly better than the above two regions, and it is expected to become an excellent ground-based observatory.
Kunlun Station is located in Dome A of Antarctica at an altitude of 4093 meters. The Chinese Antarctic expedition team first arrived in this area in 2005 and is the only country that has reached Dome A from land. Since the Chinese astronomy community participated in the inland scientific expedition at the Kunlun Station in Antarctica in 2007, it has obtained a series of astronomical observations and site survey results.
Springer Nature issued a press release to the media that whether this extremely cold and isolated environment can be the actual location of the telescope is still unknown, but the authors of the research paper pointed out that the observation capabilities of their devices will be affected by frost and overcome this. The problem is expected to increase seeing by 10-12%.
The latest published scientific research papers were completed by scientists from China, Australia and Canada. The 9 paper authors are from the National Astronomical Observatory of the Chinese Academy of Sciences, Tianjin Normal University, the Chinese Polar Research Center, the University of New South Wales in Australia and the University of British Columbia in Canada. (Finish)