For any identification of auroral radiations, a convenient method for a first approach is to represent each rotational line of a band by a rectangle of width Δ and of heightI. Δ is the width in Angstrom units of the monochromatic image of the slit on the plate andIis the theoretical intensity of the rotational line.Numerical calculations have been carried through making use of the auroral synthetic spectra which are represented by the sum of the superposed rectangles.This method explains at once the following features of the auroral bands: (a) The different aspects of theN2+bands and the structure ofRandPbranches distorted by the temperature effect; (b) the results obtained for the first positive system ofN2, where comparison of the wave‐lengths of the system as deduced from the synthetic spectra with the list of Vegard shows excellent agreement; (c) evidence for the occurrence of the O2+bands and also a possibility for identification of certain auroral emissions not yet interpreted; the absence of the first negative system, which was rather unexpected, was only apparent; and (d) a possibility for the presence of a NO system of bands.Further considerations, in particular on the excited metastable states of long life, are also repor