Magnetic field measurement for HD 129333 (2009.02 epoch). The average observed profiles of the four Fe I lines are shown with black symbols connected by thin solid lines. The grey curve in the background corresponds to ± twice the standard deviation for each pixel of the observed spectra. The thick red solid line shows theoretical spectrum for the magnetic model yielding the lowest χ² according to Fig. 5. The dashed blue line shows the corresponding non-magnetic spectrum.