LV Vulpeculae is a fast nova with a relatively smooth light curve (Raikova, 1981). On Fig. 1 the picture of the radial velocities, displayed during the outburst is shown. It is based on our measurements and the published ones (a more detailed paper will appear in C. R. Acad. Bulg. Sci.). The premaximum absorption line system (A) exhibits a rapidly decreasing velocity. It has been observed for the last time on April 17.52 (Hutchings, 1970) together with the diffuse enhanced system (B) of velocity −1260 km/s. Since the presence of the last system is an indication that the light maximum has passed, we can limit a 2h40m interval in which it had occured (on April 17.385 the brightness is still up). We assume that the light maximum has taken place at the middle – on April 17.45. On April 18 the diffuse enhanced line system, now of −1400 km/s, and the principal one (C) of −780 km/s exist. It is worth-while to emphasize that in LV Vul spectrum the diffuse enhanced system appeared before the principal one.