Images of CasA, which is about 30 degrees away from the NCP, made only using the short baselines (<1200 wavelengths). The distorted image of CasA (due to smearing and directional errors) is at the bottom of these figures. The image on the left is obtained after running SAGECal without taking CasA into account. The image on the right is after adding CasA to the sky model and running SAGECal. It is clear that the ripples on the left panel are eliminated on the right panel. Moreover, the left panel shows a “cone” directed towards the NCP where the ripples are absent. The colourbar units are in Jy/PSF.