Astronomers pinpoint the best place on Earth for a telescope: High on a
frigid Antarctic plateau

Date:
July 29, 2020
Source:
University of British Columbia
Summary:
Dome A, the highest ice dome on the Antarctic Plateau, could offer
the clearest view on Earth of the stars at night, according to
new research.

The challenge? The location is one of the coldest and most remote
places on Earth.



FULL STORY ==========================================================================
au, could offer the clearest view on Earth of the stars at night,
according to new research by an international team from China, Australia
and the University of British Columbia (UBC). The challenge? The location
is one of the coldest and most remote places on Earth.


==========================================================================
The findings were published today in Nature.

"A telescope located at Dome A could out-perform a similar telescope
located at any other astronomical site on the planet," said UBC
astronomer Paul Hickson, a co-author of the study. "The combination of
high altitude, low temperature, long periods of continuous darkness,
and an exceptionally stable atmosphere, makes Dome A a very attractive
location for optical and infrared astronomy. A telescope located there
would have sharper images and could detect fainter objects." One of the biggest challenges in Earth-based astronomy is overcoming the effect
of atmospheric turbulence on telescope image quality. This turbulence
makes stars twinkle, and measurement of its impact is referred to as
'seeing'. The less turbulence (the lower the seeing number) the better.

"The thinner boundary layer at Dome A makes it less challenging to
locate a telescope above it, thereby giving greater access to the free atmosphere," said UBC astronomer Bin Ma, lead author on the paper.

Currently, the highest performing observatories are located in
high-altitude locations along the equator (Chile and Hawai?i) and offer
seeing in the range of 0.6 to 0.8 arcseconds. In general, the Antarctic
has the potential for better seeing, owing to weaker turbulence in the
free atmosphere, with an estimated range of 0.23 to 0.36 arcseconds at
a location called Dome C.

Ma, Hickson and colleagues in China and Australia evaluated a different location, Dome A -- also referred to as Dome Argus. Dome A is located
near the centre of East Antartica, 1,200 kilometres inland.

The researchers estimated the location has a thinner boundary layer (the
lowest part of the atmosphere, which is influenced by friction from the
Earth's surface) than Dome C. Previous measurements from Dome A have
been taken in the daytime, but the authors report a median night-time
seeing of 0.31 arcseconds, reaching as low as 0.13 arcseconds.

The measurements from Dome A, taken at a height of eight metres, were
much better than those from the same height at Dome C and comparable to
those at a height of 20 metres at Dome C.

Not surprisingly, the viewing capabilities of the researchers' equipment
were also hampered by frost -- overcoming this issue could improve seeing
by 10 to 12 per cent. But the site has promise, according to Ma.

"Our telescope observed the sky fully automatically at an unmanned
station in Antarctica for seven months, with air temperature dropping
to -75C at times. In and of itself, that's a technological breakthrough."

========================================================================== Story Source: Materials provided by University_of_British_Columbia. Note: Content may be edited for style and length.


========================================================================== Journal Reference:
1. Bin Ma, Zhaohui Shang, Yi Hu, Keliang Hu, Yongjiang Wang, Xu Yang,
Michael C. B. Ashley, Paul Hickson, Peng Jiang. Night-time
measurements of astronomical seeing at Dome A in Antarctica. Nature,
2020; 583 (7818): 771 DOI: 10.1038/s41586-020-2489-0 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/07/200729114744.htm

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