Distribution of the post-fit residuals in RA and Dec, normalized by their post-fit astrometric error. Blue and red dots correspond to observations taken in this work from 568 and Z84, respectively. Green and cyan dots correspond to observations from F52 and 695, respectively, taken in 2024. Violet dots correspond to re-measurements of images from 645. Dashed circles represent values of χ equal to 3, 2, and 1.