Reconstruction of Centennial Series of Solar Activity

Abstract

The results of the digitalization of the centennial series of solar activity are considered. The data contain information on sunspots since 1918, sunspot umbra since 1917, plages since 1907, and spectral corona since 1939. In particular the digitalization of prominences from the observations in the Ca II K line in 1910–1954 and solar filaments from the observations in the H-alpha line in 1912–2002 acquired at the Kodaikanal Observatory are described. The methods of constructing composite maps of solar activity and presenting the resulting data series on the Internet are described. The long-term variations in solar activity are analyzed.