Optical spectrum for the central star of Sh2-152 (Russeil’s star number 4). Vertical segmented lines (grey) mark the spectral lines used in the spectral classification. Overlapping zones of the spectral orders are marked with red vertical lines; the low SNR causes a poor combination of the spectral orders, which could mimic a spectral line. Spectra resolution was decreased to R = 8000, to help us to discern the lines.