Test of the robustness of the spectra against changing free parameters. The seven rows show the same seven directions as in Fig. 3. The vertical dashed lines highlight the wavelength of the fluorescent channels. First column: test of the effect of multiplying and dividing the fiducial carbon density by two. Second column: test of multiplying (dividing) the Habing band UVB by 100 (2) and comparison with the result with only UVB and no radiation field from the simulation. Third and fourth columns: test of changing the turbulent velocity for C II λ1334 and Lyβ respectively. The fiducial turbulent velocity is 20 km s⁻¹.