Light curve of nova M31N 2010-10f in the optical R band (left part, nova magnitude assuming Bol 126 having constant R = 16.7 mag) and in the X-ray range (right part), assuming a nova outburst on MJD = 55 480.32 (see text). Note the logarithmic luminosity scale for the X-ray light curve and that the scale of the ordinate changes from linear to logarithmic at day 12. Error bars show 1σ confidence range, down-pointing arrows indicate 3σ upper limits. Data from different observatories are colour- and symbol-coded.