Overview of the most prominent existing TSI reconstructions using Ca II K data; see the legends in each panel for the details and references as well as Section 2 for the summary of archives used in the lower panel. Panel a): Daily values of TSI reconstructions over the year 1980 along with the PMOD TSI composite (black). The series by Oster et al. (1982) and Steinegger et al. (1996) are offset so that their mean values match that of the PMOD TSI composite over their overlapping periods, the series by Sofia et al. (1982) was an extension of Oster et al. (1982) and is thus offset to match the one by Oster et al. (1982), while the reconstruction by Chatzistergos et al. (2021a) is shown unadjusted. Panel b): TSI reconstructions with CCD-based Ca II K data. The series are offset to match their values over the 2008 minimum to that of the PMOD composite (marked by the black dot-dashed line). Shown are 180-day running means. Panel c): Long-term TSI reconstructions using Ca II K data (see Sect. 3.1 for a description of most models and Sect. 4.2 for LIRICA). The series is offset to match the value of PMOD TSI composite over 1996 (marked by the dot-dashed black line). Shown are annual median values. The numbers in the lower part of the figure denote the conventional cycle numbering.