When we talk about good places to see the night sky, we often think of places in the countryside, away from the bright lights of cities. For great places, we focus on truly remote areas. However, for great astronomical observations, there’s another important factor to consider beyond light pollution: the atmosphere.
For this reason, many observatories are built at great altitude, mid-latitude, and low humidity sites, in places like Chile for example. However, researchers are now questioning whether those are truly the best regions to study the night sky. A new paper suggests Antarctica might instead have the best conditions.
As reported in Nature, the paper measured the "seeing" above Dome A, the loftiest ice dome on the Antarctic Plateau. "Seeing" is a parameter that expresses the quality of observations as determined by atmospheric turbulence. At 8 meters (26 feet) above the summit of Dome A, researchers report seeing five times better than established observatories at mid-latitude sites.
The reason for this is the boundary layer, the part of the atmosphere where most of the turbulence takes place. Above this layer, the atmosphere affects observations less. At Dome A, the boundary layer is less than 14 meters (45 feet) thick on average. If one were to build a telescope there, it would be relatively easy to construct an observatory that is located beyond that level.
A telescope there would certainly be able to get the clearest images on Earth, all other things being equal. Unfortunately, we can’t just go and build a telescope there without some crucial technology development. The researchers report that their instruments were affected by frost, which is not something that can be underestimated as the temperatures at Dome A consistently fall below -80°C (-112°F).
If the frost can be overcome, the team suggest the seeing might improve by another 10-12 percent. Antarctica has already got its share of astronomical observatories (such as Ice Cube and the South Pole Telescope), and this work suggests it might become an even more exciting place for astronomy in the future.