SUMMARY This paper gives a new method for automatic calculation of K-indices by computer. The general philosophy of the method is the simulation of the hand-scaling procedure. The simple theory, based on the least-squares method with additional limitation of the second derivatives, is outlined. The method has two steps; in the second step the weighting factors are introduced to avoid errors connected with large variations. We call this method the Adaptive Smoothing (AS). The method was applied to data from three observatories, Belsk, Nurmijarvi and Sodankyla, for the period 1985 January 1 to 1986 February 28. The agreement with results from the hand-scaled method was 75-84 per cent. The percentage of the differences larger than one unit was less than 0.3 per cent.
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