Best-fitting non-LTE line profiles computed with the 3D model atmosphere for the WCLC (top) and Pereira (bottom) spectra. The top panels show the observed spectrum (black lines) and their theoretical best-fitting counterparts (red dots) for the different μ-angles, μ increasing from top (limb) to bottom (disk center). For clarity, a vertical offset of 0.1 was applied between consecutive μ-angles. The legend shows the best-fitting A(O) value for each of the three triplet lines. The bottom panels show the difference of the normalized intensites I^obs − I^calc. An offset of 0.01 was applied between the different μ-angles (μ increasing downwards).