Summary of the angular length re-evaluation for radio source ILTJ130738.79+270355.1. Panels A–D show the initial cutout, the removal of neighbouring sources, the masking of emission outside a convex hull based on the old angular length, and the emission that is left after masking all emission below thrice the local noise σ. The red line segments delineate the convex hull of the left-over emission, and the red points indicate the furthest removed points in this convex hull. The great-circle distance between these points is the 3σ angular length.