Wavelength dependence of IQ at the MUSE instrument’s focal plane (IQ_MUSE), analyzed using point-like sources in the MUSE fields indicated in each panel (see Table 2). The colored dots represent IQ_MUSE values derived from Moffat model fits for 44 band-filter images obtained from distinct stars within each MUSE field (individual plots available in Appendix B.2). The black open squares with error bars denote the average and standard deviation of the measured IQ_MUSE across all stars at each wavelength. The black dashed line shows the λ^−1/5 behavior of the ε₀ along the MUSE observation direction (ε_MUSE in arcseconds, top left corner), derived from average DIMM values during MUSE observations (see Table 2) using Eq. (13). The black solid and purple solid lines represent the ε₀ and ε_LE that best fit the measurements obtained for the parameters ${ϵ}_0^b$ (in arcseconds) and ${ℒ}_0^b$ (in meters) in the bottom left corner of each plot (details in text).