A large data base obtained from NASA Convair auroral expeditions is used to illustrate the variability in &lgr;6300/&lgr;4278 and &lgr;5577/&lgr;4278 ratios in auroras. The variation is well bounded by theoretical curves for characteristic spectral energies &agr; in which 0.3≲&agr;≲10 keV, which are typical for auroral precipitation. Coordinated measurements with the OV1-18 satellite show good agreement between the parameters of the precipitating proton and electron energy spectra derived from photometric measurements and those measured directly.