All panels show the superposition the LED spectrum models, fitted on each run. Each model therefore corresponds to a specific angle of incidence. Except for the IR emitter (SFH4203), the spectra at various angles can barely be distinguished from each other. The insets show the spectrum average wavelength ⟨λ⟩ = ^∫λS(λ)dλ/^∫S(λ)dλ computed on each run. This quantity varies by less than 1 Å (peak-to-peak) over a ~ 15° range. Except for SFH4203, these variations are likely to be due to residual temperature effects, which not well accounted for by the crude model used for this study.