Wednesday 30 March 2011

Is there aurora above Kilpisjärvi?

Several optical instruments measure continuously whenever the sky above northern Finland is dark. These instruments come in many versions with different purposes:

  • Meridian-scanning photometers scan the sky looking at one position at a time and measure one or more auroral emissions.
  • All-sky colour cameras have fisheye optics and nowadays image detectors with colour filter masks. Previously 16-mm or 35-mm cinematographic film was used. These cameras reproduce the aurora as it looks to the human eye.
  • Wide-band imagers are essentially sensitive black-and-white video cameras. They are useful for studying the structure (morphology) of the aurora, that is, to use the magnetosphere as a giant plasma physics lab.
  • Spectral imagers use narrow-band optical filters to measure the main auroral emissions quantitatively. From this the energy of the electrons impinging upon the atmosphere, causing the aurora, can be determined.

One of the Finnish MIRACLE all-sky camera stations is at Kilpisjärvi close to KAIRA. At the same station the University of Oulu deploys its optical instruments during the winter season. However, Kilpisjärvi is often overcast so look also at

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