Comparison between two methods to fit the centre of figure using Janus observation N1627319153_1 (resolution 0.6 km per pixel). On the left, we show the method used by Cooper et al. (2018). On the right, we show the new method relying on a complex 3D shape modelling. The vertical size of Janus on the image is about 325 pixels. The orange curve represents the equator of the moon. The cyan curve is the computed shape to be fitted to the image contour.