Achernar Hα equivalent width 1999 to 2007. + for FEROS, × for HEROS, Λfor HARPS, and ⋄ for UVES. The mean value in diskless state, 3900 mÅ, is indicated as a dotted line. The mean uncertainty of ± 160 mÅ, estimated as RMS in diskless state, is shown exemplarily in the lower right corner. Light gray triangles (▴) are photometric amplitudes of frequency F₁ taken from Fig. 4 of Goss et al. (2011). Solid disks (•) mark the depth of the excess wing signature in He i 4471 (average of the red and blue sides, see also Fig. 3) in the mean difference spectra.