The performance of SAGECal with different solution intervals. The image on the left is without multi-directional calibration. The image in the middle is after running SAGECal with a solution interval of 20 min. The image on the right is after running SAGECal with a hybrid solution interval, where solutions are obtained along bright source clusters at every 5 min and for fainter source clusters, every 20 min. It is clear that the small scale ionospheric errors present in the middle figure are mostly eliminated in the right panel. However, ionospheric variations due to decorrelation effects within the 5 min interval are still present on the right panel. The colourbar (bottom) units are in Jy/PSF.