V band photometry of AU Mon from Lorenzi1980, ASAS-3, ASAS-SN, APASS, and KWS. Upper panel: V magnitude versus MJD (bottom axis) and year (top axis, in ordinal format). The mean photometric error for each dataset is indicated by error bars at the bottom of the upper panel. Bottom panels: Lorenzi1980, ASAS-3, and KWS photometry phased with the orbital period of 11.1130374 d. Sinusoidal modulation associated with the long-cycle period is not evident in the KWS photometry, while the orbital period appears to have remained unaltered over the past decades.