Robotic Observatory Built on Remote Antarctic Summit
for National Geographic News
|February 6, 2008|
Astronomers have a new eye on the sky from what may be the best observatory location on Earth—the desolate Antarctic Plateau.
An international expedition led by the Polar Research Institute of China has assembled a fully automated observatory known as PLATO (PLATeau Observatory) at Dome Argus on the plateau's highest point.
(See an interactive map of Antarctica.)
The observatory site is so remote that humans have visited it only twice—fewer times than they've walked on the moon.
But Dome Argus is thought to offer the best view of the heavens available anywhere on the planet.
Operating in Extremes
PLATO, which consists of equipment from China, the U.S., and the U.K., was completed last month as part of a global scientific effort known as the International Polar Year.
The observatory will begin sending data by satellite in a few weeks, when darkness returns to Antarctica after the 24-hour daylight of summer.
The automated facility is powered by solar panels and, during Antarctica's lightless winter, by small diesel engines.
PLATO's seven telescopes are expected to afford views that can only be matched from space—at a fraction of the cost and with far easier access for repairs.
But the site's extreme weather poses challenges, project scientists say.
"The weather's not bad in that there are [few] high winds or storms, but that doesn't mean it's easy to work with," said Jon Lawrence, who led PLATO's development and assembly at the University of New South Wales in Sydney.
"It's at 4,100 meters [13,450 feet] of altitude, which is equivalent to something like 5,000 meters [16,400 feet] in the mid-latitudes, so that makes it difficult to work there" due to the thinner air, he said.
"And it's likely to be the coldest place on the planet, really, with temperatures down to minus 90 Celsius [minus 130 Fahrenheit] in mid-winter," he added.
"These things present various challenges in engineering."
The automated facility is built to run much like the self-contained, orbiting observatories such as the Hubble Space Telescope that provide deep-space views from outside Earth's atmosphere.
(See pictures of the Hubble Space Telescope's top ten discoveries.)
Like such space-based telescopes, PLATO features as few moving parts as possible to limit the need for repairs.
The observatory is an 18-day snow tractor ride from existing research stations 800 miles (1,300 kilometers) away on the Antarctic coast.
But even such a grueling trip is far easier than the journey required to service an orbiting facility, said Texas A&M astrophysicist Lifan Wang, who helped lead the planning for PLATO.
"In Antarctica we can always go there [to the observatory]," Wang said.
"Maybe not anytime we want to go, but at least we can plan to go there maybe once a year. That's a huge advantage."
The Chinese team is scheduled to return to the site in January 2009 as part of a 25-million-U.S.-dollar plan to maintain and expand the observatory with a permanent station.
Cold, Calm, Dry, and Dark
Astronomers have long been looking for an ideal ground-based observatory location, Wang pointed out.
Sky-watchers prefer sites with little air turbulence, which causes stars to twinkle and reduces visibility. They also seek dry air, very dark skies, and quiet weather for optimal viewing.
Currently, Mauna Kea, Hawaii, and Northern Chile's Atacama Desert are Earth's top stargazing spots, Wang said, but images from Earth's coldest, driest location—Antarctica—may be clearer and sharper by more than a factor of two.
"The Antarctic Plateau is really unique. It's very, very flat because it's covered with ice," he said.
"With no mountains the flow of the atmosphere is very steady, without much turbulence. Also, it's very cold, so the air is very dry—all the moisture is frozen."
Wang added that the area is extremely dark and typically features low wind speeds.
James Jackson, an astronomer at Boston University who is unaffiliated with PLATO, said the site's frigid temperatures will also help reduce the radiation that telescopes in warmer regions emit.
"If you're trying to take infrared pictures, the glow from the telescope itself can often overwhelm the faint infrared signals coming from space," he said.
"It would be like trying to take a picture of a distant firefly with a camera filled with glowing light bulbs."
This "cold advantage" is just one of the reasons Jackson believes Dome Argus is "almost certainly the best place in the world to put a telescope."
The observatory's telescopes are designed to take advantage of the unique Antarctic conditions.
One four-telescope set, for example, will exploit the 24-hour darkness of the Antarctic winter to continuously observe and photograph an area of the sky over the South Pole as Earth rotates.
"This cannot be done elsewhere, no matter how good the site is," Wang explained. "So this will be the first time we are going to have this kind of data on the sky."
"In this regard we're doing simple things but breaking new ground in astronomy—not only in technology but also in terms of the science we're going to produce."
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