TIR passband (in relative detector response per energy) in solid line. In addition, the SED shapes of the Moon (during the Hayabusa-2 flyby in 2015; dashed line) and Ryugu (during close-proximity operations in 2018; dashed-dotted line) are shown (arbitrary flux scale). Both SED shapes are very similar in the TIR passband. This allows for a direct calibration of the TIR Ryugu measurements via (global) lunar model predictions, without any color-correction terms.