A rocket observation of the O2(b¹Σg +-X³Σg)(0-0) atmospheric band emission at 7619 Å has been made in aurora. The observed integrated intensities of the O2(b¹Σg+)(0-0), O I 5577-Å, and N2+ 4278-Å emissions were 28, 40, and 6 kR, respectively. The observed I(7619 Å)/I(4278 Å) ratio of 4.5 is an order of magnitude lower than that obtained in recent theoretical calculations or deduced from ground-based photometric measurements. A revised calculation using recently measured auroral secondary electron spectra and a low atomic oxygen density appropriate to the flight suggests that the present result is consistent with b¹Σg+ excitation largely by energy transfer from O(¹D).