Resulting synthetic spectra (red, dot-dashed line) and observations (black histogram) for the ¹²CO and ¹³CO transitions detected in NGC 6302 with JCMT (J = 3−2) and Herschel/HIFI (J = 6−5, 10−9, and 16−15). The parameter θ_BW stands for the HPBW of the telescope beam at the given frequency, while I_f refers to the intensity factor applied to the model to account for the uncertainties in the radiative transfer solving of the model and in the calibration of the observations, which enable a good fit to each spectrum.