Opacity maps of c-C₃H₂ 2_1,2 –1_0,1 for all 15 investigated velocity components. In each panel, the velocity of the channel is given in km s⁻¹ in the bottom left corner, the beam (HPBW) is shown as an ellipse in the upper left corner, and an approximate physical scale for the assumed distance of the cloud (see Table 3) is indicated in the bottom right corner. A star in the upper right corner marks the components with a maximum S/N τ/σ_τ smaller than 5 (see Fig. 7). The equatorial offsets are relative to the phase centre.