Same legend as in Fig. 2, for the bands of interest for the calculation of the s index and IRT index. The panels show these bands: V band (389.1067 nm–391.1067 nm), K line (393.3664 nm), H line (396.847 nm), R band (399.1067 nm–401.1067 nm), V band for IRT (847.33 nm–847.83 nm), 1st triplet line (849.8 nm), 2nd triplet line (854.2 nm), 3rd triplet line (8662 nm), and R band for IRT (870.24 nm to 870.74 nm).