Sequence of the Hα wideband (Col. 1) and narrowband (Cols. 2–8: −1.03 Å, −0.77 Å, −0.26 Å, the Hα line center, +0.26 Å, +0.77 Å and +1.03 Å) images of the ROI, which is indicated with a solid box in Fig. 1b, including the respective maps of DS at ±0.77 Å (Col. 9) and FWHM (Col. 10). Respective times of observation are shown along the right ordinate. This figure is accompanied by a movie. The rightmost column for the FWHM, which is present in Fig. 2, is not included in the movie.