NH₃ (1, 1) and (2, 2) integrated line emission in the velocity range (−1.2, +0.5) km s^-1, overlaid on the 70 μm continuum of Herschel/PACS. The white contour is the same as depicted in Figs. 1 and 2. The fully sampled area is indicated by the white square. The white triangle (circle) points to the position of the NH₃ (CO) peak. NH₃(1, 1) starting and spacing contours (yellow) are 0.12 and 0.06 K km s^-1, respectively. NH₃(2, 2) starting and spacing contours (blue) are 0.04 K km s^-1. In this velocity range, the ammonia emission is dominated by a ring-like structure towards the outer part of the ring nebula (see text).