Comparison of automatic flux measurements by LSDCat (F_Kron) with fluxes measured manually by curve-of-growth (F_COG) integration, for a sample of 60 Lyman α emission lines in MUSE datacubes. The automatic measurements were extracted according to Eq. (26) and Eq. (27), using spatial apertures of 2R_Kron (blue symbols) and 3R_Kron (green symbols) and adopting S / N_ana = 3.5. The manual method used to measure the fluxes is explained in Sect. 3.4. The black diagonal line indicates the 1:1 relation. The gross deviation for the brightest object in the sample is caused by a strongly double-peaked Lyman α line profile with significant peak separation. Here the narrow-band window automatically determined by LSDCat treated the stronger peak as a single emission line, while the trained eye was able to adjust the window accordingly to include both peaks.