A location in East Antarctica could be an ideal location for an optical observatory, researchers say

An observatory in the heart of Antarctica offers the brightest view of the entire night sky.

If an optical telescope were built on a tower of a certain height in the middle of the Antarctic plateau, it would notice celestial features about half the size of what other observers commonly see, researchers report online in December. in Nature. The observatory achieves such a clear view by looking at the lowest layer of the atmosphere known as the boundary, which is responsible for most of the discrete winds disturbing the telescope images (SN: 10/4 / 18).

The thickness of the soil boundary layer varies around the world. Near the equator, it can be hundreds of feet thick, limiting the view of world-class telescopes in places such as the Canary Islands and Hawaii (SN: 10/14/19). These telescopes usually do not see celestial features less than 0.6-0.8 arc seconds – the shining width of a human hair at a distance of about 20 meters.

“But the border is very fine in Antarctica,” said Bin Ma, an astronomer at the Chinese Academy of Sciences in Beijing. “So it is possible to put a telescope there.”

Ma and her colleagues first carried out nocturnal atmospheric collapse measurements from the highest point in East Antarctica, Dome A. From April to August 2019, the instruments of an 8-meter tower of top of the Chinese research station Kunlun monitored the turbulence in the Earth’s atmosphere and disrupted the lighting incident. A nearby weather station also monitors atmospheric conditions such as temperature and wind speed. Using these observations, the researchers were able to describe the boundary of Dome A and its effects on telescope observations.
The demarcation line measures on average about 14 meters thick; As a result, the light sensors at the top of the 8-meter tower are free from unlimited layer blur for only a third of the time. However, when these instruments are above the layer, atmospheric interference is so low that a telescope will see, on average, details in the sky 0.31 arc second in width. Under the best recorded atmospheric conditions, a telescope can see characteristics of less than 0.13 arc second.

“A tenth of a second arc is very good,” said Marc Sarazin, a physicist at the European Southern Observatory in Munich, who was not involved in the work. It is “really something that is seldom done in Chile or Mauna Kea” in Hawaii.

The researchers found the same boundary at another place on the Antarctic plateau known as Dome C. However, the boundary layer is around 30 meters thick, making it difficult to build an observatory above it. An optical telescope attached to build a 15-meter tower at Kunlun could use views of stars from Dome A over the border, Ma said. Such razor-sharp telescope images will help astronomers study a range of celestial objects, from bodies in the solar system to distant galaxies.

 

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