Rectification of a CTIO/CHIRON echelle spectrum (ktc00027) in the region of the Hα line (6563 Å), using the resimplex3 method. Top: Synthetic spectra were computed from our model in Table 1, ‘all-data’ column. Four component spectra (Aa, Ab, B, C) and the resulting spectrum are plotted. Second row: Observed spectrum from CHIRON (black), orders r = 39 to 41, and the corresponding blaze function (green). Third row: Rectified spectrum (black), its comparison to the synthetic spectrum (blue), and corresponding residuals (red). The rectification was done with respect to the continuum level, with interpolation of the blaze parameters over wide lines (cyan) and problematic orders, also avoiding locations of the telluric lines (green). Bottom: Residuals plotted separately.