Normalised intensity of 3C 454.3 subtracted from the normalised intensity of the object PSFs, as a function of distance from the PSF centroid. The reference profile is the PSF of quasar 3C 454.3 (black solid (0, 0) line). The calibrator star profile (blue dashed line) is the narrowest. The Vesta PSF (dashed magenta) is wider than the calibrator star, but still narrower than the reference PSF. The filled grey area represents the uncertainty of the nine Pluto observations. The mean median (MM) Pluto profile is shown as the green solid line. The most realistic dust ring model detected at 3σ significance level is plotted as the red dotted line.