Dither points from commissioning and cycle 1 calibration, with each panel illustrating the outline of each channel’s slicer. The black crosses correspond to the dither pattern of 10 Lac executed during PID 1524 (observation 16), optimised to characterise the intra-slice distortion. The red points correspond to the point and extended dither pattern optimised for channel 1 (PID 1050, observation 9), and the violet points correspond to the point source dither pattern of channel 3 (PID 1049, observation 2).