Residuals of transforms from IFU slices to FPA with G395H. Left panel: distribution in the detector focal plane. The errors increase toward the lower left, where the CAM distortion was not influenced in the global fit and is not optimal for the IFU, but remain <0.25 px. Right panel: histograms of residuals in pixels in i and j direction (top, middle) and absolute residuals (bottom). Shown in red are the confidence limits of 68.27% around the median at −0.054 and + 0.058 (i), and at −0.004 and + 0.009 (j), and the limit of 68.27% of absolute residuals (0.068).