LOFAR-HBA Stokes-I images of the NCP at frequency 113.9 – 127.1 MHz. All 69 sub-bands are combined for imaging after the DI calibration (top row) and DD calibration (bottom row). The DI and DD calibrations are performed by SAGECAL and the images are deconvolved by WSCLEAN. Left column: 20° × 20° image with a pixel size of of 0.8 arcmin with baselines between 50–1000λ after DI calibration (top) and after DD calibration (bottom). Right column: Zoomed 4° × 4° image with a pixel size of of 0.2 arcmin with baselines between 50–5000λ after DI calibration (top) and after DD calibration (bottom).