engleski

Determination of the Kanzelhoehe sunspot group positions: manual versus automatic method

For the investigation of possible variations of the solar rotation, sunspots and sunspot groups are very often used as tracers, mainly because of the long term data sets available from various observatories. Until now, for the investigation of temporal variations of the solar rotation using sunspot groups as tracers, the Kanzelhoehe data set was analysed only for the period 1947-1981. Our aim is to provide a continuation of that previous investigation. For this reason we processed Kanzelhoehe sunspot drawings for solar cycles nos. 20-23 (manual method) and Kanzelhoehe white light images for solar cycle no. 24 (automatic method), covering almost the 41 year period, 1964 - 2015. When both methods for the heliographic positions determination have been used, it is important to compare them. Here we present the results of the manual versus automatic method comparison (differential rotation coefficients for both methods, differences in the identi cation of the sunspot groups, differences in the number of identi fied sunspot groups, etc.) performed for the year 2014.

sunspot groups positions, differential rotation, differential rotation coefficients

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