a) NGC 23: PMAS observed (not corrected for extinction or underlying stellar absoption) maps of emission line ratios: [O iii]λ5007/Hβ (top middle), [O i]λ6300/Hα (top right), [N ii]λ6584/Hα (bottom middle) and [S ii]λλ6717, 6731/Hα (bottom right). Also shown are the maps of the observed Hα flux (top left) and EW(Hα)_em (bottom left) of the line in emission. The FoV of the PMAS maps is 16″ × 16″, and the orientation is North up, East to the left. The crosses on the maps mark the peak of the PMAS optical continuum emission at ~6200 Å  (see Paper I for details). The Hα maps are shown in a square root scale to emphasize the low surface-brightness regions.