MRS spectro-photometric correction based on flight data. Top: Colored curves showing the MRS point source integrated spectra in different spectral bands for the A-star HD 163466, which were reduced using the ground-based spectro-photometric solution. The spectrum is cut at 23 µm due to the S/N on the source becoming too low beyond that point. A spectral continuum is determined for each spectral band (black solid line). By comparing the manually defined continuum to the theoretical continuum of the A-star, based on Gordon et al. (2022), a 1D spectro-photometric correction vector is derived for each spectral band. After introducing this correction, the A-star data are reduced once more. The resulting spectrum is shown by the red line. Bottom: One-dimensional spectro-photometric correction vectors. The prominent emission feature at 8 µm is an artifact from the MIRI FM ground test campaign. This artifact is corrected in the in-flight spectro-photometric solution. The dotted red line shows the location of the MRS spectral leak at 12.22 µm (see text for further details).