12/9/2023 0 Comments Thirty meter telescope site![]() If the local population were to grow with economic development, then control of light pollution could be lost. However, this does not mean that industrial development will not occur in the future. Qinghai Province on the Tibetan Plateau has a very low population therefore, problematic artificial light sources are at present non-existent. Light pollution is mainly the result of human activities. A detailed analysis is given in the following.įor any modern observatories for night optical/infrared astronomy and planetary sciences 9, the first factor to consider is undoubtedly the clarity of nights, followed by the darkness of the night sky (that is, avoiding light pollution), among other parameters important for advanced modes of observations. Comprehensive comparisons of the key site characteristics of Lenghu with those of the other known best astronomical sites in the world are summarized in Table 1. All the measurements and preliminary statistics of the raw data are updated daily and are available at. ![]() This could not have been accomplished without the great assistance from the local government of Lenghu Town. Shortly after the initial site reconnaissance, to start the site monitoring as soon as possible, the building materials and tools were carried to the site by a helicopter and the scientific devices were manually carried up to the mountain in September 2018, before the road reached the site. As DIMM seeing must be measured in the vicinity of a telescope project and at a similar height from the ground as the telescope, a 10-m tower was built to mount the DIMM. The main site parameters-including cloudiness and night-sky background brightness, air temperature, pressure, humidity, wind speed and direction, dust, precipitable water vapour (PWV), and, most importantly, seeing (using a differential image motion monitor (DIMM) 7, 8)-have been monitored starting at different times from March 2018 onwards (summarized in Extended Data Table 1). The geographic information of the site, Lenghu in Qinghai Province, is summarized in Methods and Extended Data Fig. The precipitable water vapour is lower than 2 millimetres for 55 per cent of the night. The median night temperature variation is only 2.4 degrees Celsius, indicating very stable local surface air. Of the nights at the site, 70 per cent have clear, photometric conditions, with a median seeing of 0.75 arcseconds. 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. The altitudes of the potential locations are between 4,200 and 4,500 metres. ![]() 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 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 astrophysics 3, 4, 5. 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 sites 1, 2 (all in the Western Hemisphere). On Earth’s surface, there are only a handful of high-quality astronomical sites that meet the requirements for very large next-generation facilities.
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