The Sun's Activity: A Review of 2018
The decline in solar activity was even more visible in 2018 than in the previous year. As in previous years, the northern and southern hemispheres behaved differently: at times, activity in the southern hemisphere exceeded that of the northern hemisphere, at other times it was the other way around.
Anyone who observed the sun regularly in 2018 was able to see the end of the 24th activity cycle, which is still ongoing, with their own eyes: conspicuous spots, bright flares and solar flares were even rarer than in the previous year. A special feature of this cycle is that the activity of the northern and southern hemispheres of the sun did not fluctuate in unison: first the southern hemisphere and later the northern hemisphere reached their maximum. But even in the shorter period of 2018, the scene of events changed between the two hemispheres. Apart from that, the activity of the sun remained at a low level throughout the year. A total of only 38 spot groups could be observed, which compared to the previous year with its 68 groups was almost half …
Sun activity in 2018: Tables of relative numbers
The tables reproduced in the PDF document contain the overview of the solar activity in 2018 as well as the relative numbers of the SONNE network for the months January to December 2018. For comparison are the data published by the Solar Influences Data Analysis Center (SIDC). given according to the new counting method valid since July 1, 2015 (see SuW 10/2015, p. 66). The tables supplement our report "The activity of the sun: review of the year 2018" in SuW 6/2019, pp. 68 - 71.