Left panel: analysed radial profiles of stars of varying brightness. We clipped the radius range to balance their contribution against the high-quality radial profile of HD 1973 (shown in green, upper right) and the high-S/N PSFex radial profile at the PSF core based on thousands of bright unsaturated stars (depicted in red, lower left). This approach ensured that the aggregate profile leverages both the detailed observation of a singularly bright star and the precision afforded by PSFex in the PSF’s core regions. Middle panel: optimisation step involved in aligning all profiles to achieve coherence across the data set. This optimisation process is critical for synthesising a unified radial profile from the disparate data points provided by stars of different magnitudes and the detailed profiles of HD 1973 and the PSF core. Right panel: final VIS extended PSF. The profile has been normalised to a base surface brightness of μ₀ = 0 (corresponding in that case to a I_E = 3.1 mag star). This standardised profile serves as a comprehensive model of the VIS PSF’s behaviour across a wide range of radii.