Over the years there have been numerous theories advances to explain the production of the O(1S) state in aurora as well as the fact that the variation with altitude of the emission from O(1S) is the same as that from the N2+ first negative (1 NG) band system. In reality the source function for O(1S) does not covary with N2+(1 NG) but has a smaller scale height. The covariation is due to quenching of the source function by O(3P). In a flight of the Michigan Airglow Payload into a remarkably steady aurora the profile of 5577-¿ was obtained. The steadiness of the aurora allows the profile to be differentiated for direct comparison to theory. By using the simultaneous measurements of the secondary electron flux and ionospheric densities the electron-atom impact and O2+ dissociative recombination source functions are found to be inadequate below 160 km. The remaining source can be adequately explained by N2(A3&Sgr;)+O→O (1S)+N2.