F_γ/F_opt ratio for several classical novae. t_peak is the time when the peak in optical data is reached. The ratios from V1723 Sco and V6598 Sgr are calculated using the γ-ray fluxes and V-band magnitudes from Figure 1. The optical fluxes are extinction corrected. For both novae, the uncertainties are at 1σ level and are dominated by the uncertainties on the γ-ray flux. The other ones are taken from the Supplementary Figure 3 from Li et al. (2017).