Comparison of the observed spectra of C/2016 R2 obtained at the edges of the slit (nucleocentric distance ~6000 km, averaged at four different lines at the two extremities of the slit) with the model. The upper and lower parts corresponds to two different wavelengths intervals. Some CN emission lines, not reproduced by the model, appear in the region around 3880 Å. The observational data are plotted in blue, and the modeling is shown in red. For more clarity, the wavelengths of the observed lines are given by vertical bars above the spectra. The R branch is degraded to the blue side, and the P branch is first degraded to the red side and returns to the bluer wavelengths after the bandhead. The first three ^PQ₁₂ and ^RQ₂₁ satellite lines are also plotted above (vertical black bars at about 3910 Å). Their intensity is negligible compared to the P or R lines for higher values of N.