Resolution of the (OI) + NH2 blend in Comet P/Halley

Spectra of P/Halley were taken at very high resolution (0.15A) to evaluate contamination of the forbidden oxygen doublet by NH2 features at low resolution. Comparison is made with other bright comets. Appreciable variations are found in the NH2/(OI) ratio and in the relative intensities of the NH2 emissions themselves. The accuracy obtained on the oxygen abundance derived from the (OI) lines is discussed. Mapping of these emissions over the coma is required to correctly remove any important NH2 contribution at low resolution. This should also provide information on the origin of the oxygen atoms in the 1D level.