Observing sites and phase distribution of the data. Left panel: MUSICOS sites involved in this work, namely Observatoire Haute-Provence (OHP), Xinglong Observatory (BXO), Kitt Peak National Observatory (KPNO), ESO La Silla (ESO), La Palma (INT), and Mt. Stromlo Observatory (MSO). Right panel: phases of the observations plotted against the reduced Julian Date. Different colors denote different instruments (see legend). Observations plotted with filled circles were used for Doppler imaging, while the empty circles denote omitted observations. The vertical dashed lines separate the four subsets used for Doppler imaging.