Film readings for the FMI-1977 all-sky camera
The so called film-readings (or all-sky camera summary tables) are manually created by viewing the photographic records which are made on 16mm colour film at a typical rate of one frame per minute. Data is recorded at higher frame rates (up to six frames per minute) during selected periods. The start and stop time of camera operation and an average over the hour of auroral intensity and weather conditions is included in the tables. Most of the data has been digitalized by Peter Amberntsson (many thanks to him for doing this tedious work).
The film readings (i.e. the ASC summary tables) are ONLY intended to give information when data is available. They should be used with extreme care in statistical studies. This is the case since many people has been reading the films over the years, using slightly different criterias for the legends. Also, more effort has been spent during interesting periods (campaigns, etc.), which causes a significant bias on the data set. Finally the difference between some legends are not well defined causing further degradation of the statistical quality of the film readings.
|r||Some red aurora.|
|R||Strong red aurora.|
|/||No aurora, clear weather.|
|–||Camera off (camera not running due to daylight, snow or rain)|
|ac||Aurora and clouds.|
|rc||Red aurora and clouds.|
|Ac||Strong Aurora and clouds.|
|Rc||Strong red aurora and clouds.|
For further information please contact Urban Brändström