The best place to see the night sky is the highest dome on the Antarctic plateau, the coldest known place on Earth, where the stars seem to “shine” the least.
Dome A, or ‘Argus’, located in the center of East Antarctica at a height of 13,428 feet above sea level, experiences temperatures as low as -144 ° F.
Researchers from Australia and China designed, built, and established a small telescope system in the ice dome, where atmospheric turbulence is low.
This turbulence, which causes light to bend when it makes the last leg of its journey to the ground, is what makes stars appear to blink when viewed from Earth.
The best place to stargaze is the highest dome on the Antarctic Plateau, the coldest known place on Earth, where the stars “twinkle” the least. In the photo, the Antarctic night sky (stock image)
Researchers from Australia and China designed, built and established a small telescope system, pictured here, in the ice dome, where atmospheric turbulence is low.
“After a decade of indirect evidence and theoretical reasoning, we finally have direct observation evidence of the extraordinarily good conditions at Dome A,” said author and article astronomer Michael Ashley of the University of New South Wales.
“Dome A is the highest point in the central Antarctic plateau region, and the atmosphere is extremely stable here, much more so than anywhere else on Earth.”
“The result is that the twinkling of the stars is greatly reduced and the images of the stars are much sharper and brighter.”
The researchers placed their telescope system, the KunLun differential imaging motion monitor, which has an aperture of 25 centimeters (5.9 inches), on a 26-foot-high platform above the surface of the dome.
This raises the telescopes above the steep temperature gradients that are close to the surface of the ice, as well as atmospheric eddies, which can interfere with stargazing efforts.
Turbulent eddies accumulate as the wind moves through changing topographies like hills, mountains and valleys, Professor Ashley said.
“This causes the atmospheric turbulence that doubles the starlight, so when it hits the ground, it is all over the place and you get these blurry images,” he explained.
Located in the center of East Antarctica at a height of 13,428 feet above sea level, Dome A, or ‘Argus’, experiences temperatures as low as -144 ° F. In the photo, the summit of Dome A
Dome A, however, features a plateau that is flat for many hundreds of miles in all directions, which means that its atmosphere is relatively stable.
“There is a very slow wind that blows across the plateau that is so gentle that it doesn’t generate much turbulence,” explained Professor Ashley.
‘The little turbulence we see is restricted to a very low’ boundary layer ‘: the area between the ice and the rest of the atmosphere.
“We measured the thickness of the boundary layer at Dome A using a radar technique about a decade ago and it averages about 14 meters, but it fluctuates, drops to almost nothing, and rises to about 30 meters.”
The researchers placed their telescope system, pictured, which has an aperture of 25 centimeters (5.9 inches), on a 26-foot-high platform above the surface of Dome A
By placing the KunLun differential imaging motion monitor on top of a 26-foot-tall tower, the team found that it is above the boundary layer about a third of the time.
In fact, the system, which takes a picture of the sky every minute, took 45,930 images from above the boundary layer between April 11 and August 4, 2019.
According to Professor Ashley, however, proving that Dome A provided the best place on Earth for stargazing was no simple feat.
“It was very difficult because observations should be made in mid-winter with no humans present,” he added.
Consequently, the infrastructure used (the power source, computers and satellite communications) had to be “remotely managed,” he said.
During winter, Antarctic latitudes offer much longer nights, providing continuous windows for stargazing that allow more during observations.
One might ask, if the atmosphere is an obstacle to making clear astronomical measurements, why do scientists bother with ground-based telescopes when we have the ability to observe observatories, like the Hubble Space Telescope.
“Satellites are much more expensive, we are talking about factors of 10 to 100 times the cost,” explained Professor Ashley
“Another advantage of making Earth-based observations is that you can always add the latest technology to your telescope on the ground, while in space everything is delayed.”
Furthermore, he added, “Many modern integrated circuits cannot be easily used because they are not radiation hardened.” Then you end up with the technology space lagging behind for 10 years or more. ‘
Dome A, or ‘Argus’, located in the center of East Antarctica at a height of 13,428 feet above sea level, experiences temperatures as low as -144 ° F
With their initial comprehensive study, the researchers are now considering how the astronomical potential of Dome A could be better exploited.
“Dome A is an excellent site for astronomical observations, and we must do everything possible to participate in an international project to place a large telescope there to take advantage of the conditions,” said Professor Ashley.
“With Antarctica so close to Australia, it is a great opportunity.”
The full study findings were published in the journal Nature.
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