Top panel: The Hip1 NDAC and FAST residuals plotted against eachother. Bottom panel: The same residuals in the top panel, but each pair has been transformed to the decorrelated basis using the correlation coefficients provided by the IAD. A beautifully symmetric 2D Gaussian is recovered. Note that the bullseye is nearly the same (very symmetric) even if the as-published IAD residuals are used instead of the Gaia recalibrated ones. Two red contours (at arbitrary levels) are shown to emphasis the symmetry.