Carrington maps constructed from the observations of nine Hα archives. Each column shows Carrington maps for the same rotations 1427 (7 May to 2 June 1960, left, see also the left column of Fig. 7), 1689 (30 November to 26 December 1979, middle), and 2141 (1 to 27 September 2013, right, see also the bottom row of Figs. 1–4). All maps show contrast values in the range [−0.5, 0.5].