Examples of the NCP field maps at different time-scales. Where present, the area within the black circle indicates the portion of the image searched for transients. This was the same for each time-scale and had a radius of 7|$_{.}^{\circ}$|5. Upper left panel: an image on the 30 s time-scale which was observed on 2012 January 9. Using projected baselines of up to 10 km, the map has a resolution of 4.2 × 2.3 arcmin (synthesized beam position angle [BPA] −39°) with a noise level of 1.9 Jy beam⁻¹. Only the source 3C 61.1 is detected at a 10σ level, and this source is marked on the image. Upper right panel: an 11 min snapshot observed on 2011 December 31. The noise level is 320 mJy beam⁻¹ and the resolution is 5.6 × 3.6 arcmin (BPA 43°). The number of detected sources at a 10σ level is now ∼15. Lower left panel: an example of the longest time-scale images available of 297 min, constructed by concatenating and imaging 27, 11-min sequential snapshots. Observed on 2012 February 4, this image has a resolution of 3.5 × 2.0 arcmin (BPA −6°) and a noise level of 140 mJy beam⁻¹, with ∼50 sources now detected at a 10σ level. Lower right panel: a magnified portion of the lower left panel image. The colour bar units are Jy beam⁻¹.