Measurements of the auroral atomic oxygen (3P--1D) emission line at 6300 ¿ made by the Atmosphere Explorer visible airglow experiment are analyzed using a tomographic inversion. Emission altitude profiles are compared to the results from an electron transport and chemical reaction model. The model incorporates measurements of the energetic electron flux, neutral composition, ion composition, and electron density. Reasonable correspondence is obtained using primarily the ''classical'' sources of O(1D) excitation: electron impact on atomic oxygen and dissociative recombination of O2 +. The reaction of N(2D) with O2 is considered to be a minor source. Small contributions are also calculated for cascade from O(1S), electron impact dissociation of O2, reaction of N+ with O2, and energy transfer from O+(2D) and thermal electrons to O(3P). A possible minor source from the quenching of N(2D) or N(2P) by O(3P) is also discussed. ¿ American Geophysical Union 1988