Doppler image (brightness maps) of DF Tau on a flattened polar view. The central dot illustrates the rotation pole, the two dotted circles are latitude 60° and 30°, and the solid circle represents the equator. The black ticks show the clockwise rotation phases, and the red ticks represent the observed phases. The colour-coding indicates the brightness on a linear scale, where a value of 1 represents the quiet photosphere. Values lower than one are darker regions, and values greater than one are bright.