Spectral evolution of NVul24 for the first 50 days of the outburst. The sequence of sample spectra were obtained in low dispersion with the Asiago 1.22 m + B&C (day +11, +16, +24) and in high resolution with the Varese 0.84 m + Echelle (day +0, +1, +2, +4, +7, +34, +42). The latter were Gaussian smoothed and binned to reduce their spectral resolution to match that of the Asiago 1.22 m + B&C spectra, for an easier intercomparison. The native absolute fluxing of all the spectra has been checked against the AAVSO photometry of Fig. 1, and dereddened by E_B − V = 1.6. The offset in flux applied to the spectra for a clearer plotting is indicated in green.