Photometric data of V838 Mon. Colour-coding refers to the data from the various observatories, and different symbols indicate the various photometric bands. The grey area shows the period of the SAAO observations in the beginning of 2007. The U-band measurements from SAAO are marked in red, to distinguish them from the B-band values of similar magnitude. The vertical lines mark the dates with our low- and medium-resolution spectra.