Long-slit spectrum of comet C/2014 N3 obtained on 5 December 2015. Panel a: energy distribution in the observed spectrum of the comet (black line) and the scaled solar spectrum taken from Neckel & Labs (1984, red line). Panel b: polynomial fit of the ratio of the cometary spectrum to the solar spectrum. Panel c: emission spectrum of the comet derived by subtracting the fitted continuum from the observed spectrum.