Emission of the NO &ggr; (1,0) band at 2150 A has been observed by a rocket-borne spectrophotometer in an IBC II+ aurora. The v'=0 progression of the &ggr;-system does not appear in the spectrum. The observed emission rate of the 2150 A feature increases relative to N2+ first negative band emission with increasing altitude. We suggest radiative recombination of NO+ ions with electrons as a possible excitation mechanism compatible with the data.