Residuals after nightly shift correction and subtraction of average profile plotted as a function of velocity and time modulo period, where the period is fixed at the formally estimated value of P = 0.678 d. The coherent structures along the diagonals in this plot are evidence of activity zones (in emission or absorption) moving with stellar rotation and therefore crossing the line profile. The good match of starspot features over several nights is a strong indicator of a structured surface on Vega.