PSF model. Left: Spectral comparison between the quasar and PSF star used to derive the PSF scaling factor. The extracted 1D spectra from the quasar (black) and PSF star (blue) were obtained using a circular aperture with radius 0$\stackrel{″}{.}$35. The PSF spectrum is scaled down by a factor of 500 for visual comparison. While the PSF star shows a smooth stellar continuum, the quasar exhibits a prominent broad Hβ emission line and strong Fe II features. The wavelength-dependent scaling factor S(λ) computed as the ratio between the quasar and PSF spectra is shown in green. The scaling factor is smoothed with a Gaussian kernel of width σ = 5 pix before being applied slice by slice to the aligned PSF cube. Right: Median radial profiles extracted from the quasar cube (black dashed), the raw PSF star cube (orange), and the PSF star cube, corrected with the wavelength-dependent scaling factor (blue). The radial profiles are measured from the brightest pixel in white light of each cube. The colour-shaded areas correspond to the median absolute deviations of the quasar radial profile (grey) and the scaled PSF star cube (blue).