Arctic turbulence profiler

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The polar regions have the potential to provide the best astronomical observing conditions on Earth. Antarctica has been shown to offer outstanding conditions for observations over a wide range of wavelengths and is the favoured site for a number of new telescope projects. There is every indication that Canada's Arctic may provide the same scientific benefit as the Antarctic, while at the same time being more accessible. However, the astronomical quality of potential sites in the Arctic have never been explored.Ellesmere Island contains the northernmost mountain range in the world, with peaks as high as 2600 metres. It is a very dry place and may well be ideal for astronomy. Our team is conducting a program to assess the quality of several mountain top sites in Northern Ellesmere Island. To this end, small site-testing stations have been put in place on three mountain-top sites. These stations include an all-sky sky camera, weather instruments, and a small wind generator. To this we plan to add a new type of instrument, developed at the University of British Columbia. The Arctic Turbulence Profiler will use moonlight to measure the strength and distribution of atmospheric turbulence above the sites. This turbulence is responsible for the blurring of images taken by ground-based telescopes, and its measurement is key to assessing the performance of any future astronomical observatory that might be established.The Arctic Turbulence Profiler is a small instrument that contains sensitive silicon photodiodes that measure the intensity of moonlight falling on them. By measuring correlations in the "twinkling" of the moon, as seen by the different detectors, we are able to reconstruct the distribution of atmospheric turbulence in the lower several hundred metres, as well as determine the total effect of the whole atmosphere above the site.