AC Her position–velocity diagrams found along different position angles from 0° to 170° with a step of 10°. The PA is indicated in each panel in the top right corner. The name of each quadrant is indicated in the panel showing the first velocity channel. Contours are the same as in the corresponding channel maps (Fig. 1). To help in the identification of the Keplerian dynamics, we show hyperbolic functions in each panel.