The Arctic Stars Are Brightest

Evidence that Canada's High Arctic might be the best place in the world for telescopes could mean big things for astronomy.

New research suggests that the skies of the Canadian Arctic may be the best in the world for astronomy.

Researchers from the Universities of British Columbia and Toronto and the Herzberg Institute of Astrophysics in Victoria are about to report initial results indicating that the best place in the world for telescopes might be Ellesmere Island in the Canadian High Arctic.

Led by Dr. Paul Hickson of UBC, the research was conducted at the Polar Environment Atmospheric Research Laboratory (PEARL), a remote lab perched on a ridge overlooking Eureka – the most northerly permanent scientific base in the world, a mere 1,100 km from the North Pole. The results indicate that the clarity of the sky, which astronomers call “seeing,” might be as much as 40 per cent better than anywhere else on the planet.

To image planets, stars, and galaxies, skies need to be both dark and still. City dwellers are intimately familiar with the orange glow in the sky caused by light bouncing off particles suspended in the atmosphere. Pointing a research telescope through such murky skies is futile, so astronomers need to get away from cities.

But the relative “stillness” of the atmosphere is what really drives astronomers to exotic locales. From perhaps the age of three, we all know that stars twinkle. This poetry inspiring process is actually caused by light passing through the atmosphere. While the air around us feels almost entirely uniform, it has subtly different densities and temperatures. Light passing through these differences will be bent, or more correctly, refracted.

This isn't a big deal for our eyes. They're too small to really be impacted. But for a telescope that's eight metres in diameter, it's a big problem. The constantly moving atmosphere blurs and smears the images to the point where the telescope performs like one much smaller. To solve this problem you can either go to space, like the Hubble Space Telescope, or you can try to correct for all the bending of light, a technique known as Adaptive Optics.

While all large optical telescopes use adaptive optics now, their performance is still acutely limited by the quality of the seeing. Looking through really good skies allows you to take astronomical images and data much, much faster. Improving the seeing by just 25 per cent means you can take data in half the time and do a lot more science. So it's no surprise that astronomers continually search for the best seeing possible.

For many years it was believed that the seeing high atop the ice cap of Antarctica was the best, and 2004 research by an Australian collaboration appeared to confirm this conclusion. But nobody had measured the seeing at an analogous place in the Canadian High Arctic. Until now. The Canadian team's result has come as a stunning surprise. “We were amazed at what we saw when the first data came in,” says Hickson.

The finding has practical implications as well. The South Pole is expensive to reach and a dangerous environment for both equipment and people. The Canadian Arctic, with its frigid -35 C average winter temperature, is still over 20 C warmer than the South Pole. It's also accessible year-round, a potentially life-saving difference.

Despite the “warmer” temperatures, Hickson's team had a constant battle against the elements to take the data. While the PEARL station is in a polar desert, and the skies are clear almost five days a week on average, the weather can be intense the rest of the time. One severe storm even broke their measuring equipment. “We didn't anticipate how difficult it would be and we've had to learn a lot – quickly,” says Hickson.

However, astronomers are more than prepared to work around these problems if it leads to better data.

Hickson says there is still much to learn about the skies over Ellesmere. Their initial measurements have only placed constraints on the lower levels of the atmosphere and they need to know more about the higher reaches. They are planning to take more data in the winter of 2010 with some additional equipment.

When probed about the kind of telescopes that could be put on Ellesmere, Hickson, aware of environmental concerns, is conservative. “We need to start small and learn about operating in that environment, both from a scientific and ecological perspective,” he says. But he emphasizes even a telescope with a diameter of two or three metres could have image quality comparable to that of the Hubble Space Telescope, for 1/1000th of the cost, and take surveys of the northern skies in short periods of time.

He is also keen to emphasize the home-grown potential here. “Canada's astronomers were ranked No. 1 in the world by Thompson/ISI in 2005. We achieved this success by using powerful telescopes primarily located in Hawaii and Chile. It's exciting to think that sites in the Canadian High Arctic appear to rival these places and might be the best anywhere.”