Fig. 9
From: Performance of Akatsuki/IR2 in Venus orbit: the first year
Examination of geometrical distortion in IR2 images. a Residual vectors plotted in the star-field image on which astrometry was performed. The vectors are magnified by a factor of 40. b Systematic behavior of residuals examined by plotting them against distances from the image center. Since the geometrical distortion of the optics origin is expected to be the point symmetry relative to the image center, this plot suggests that the distortion in the IR2 image is negligible