Wilkes, BelindaFerland, GeorgeHanes, D.Truran, J. W.2017-06-081981Wilkes, B. J., G. J. Ferland, D. Hanes, and J. W. Truran. 1981. “On Nitrogen Abundances of Planetary Nebulae.” Monthly Notices of the Royal Astronomical Society 197 (1) (November 1): 1–6. doi:10.1093/mnras/197.1.1.0035-8711http://nrs.harvard.edu/urn-3:HUL.InstRepos:32955260Observations of N II recombination lines in the planetary nebula NGC 3242 are presented which allow the first temperature independent measurement of the nitrogen abundance of a nebula. Model nebula calculations are utilized to identify a reliable N/H indicator. The standard technique employing strong forbidden lines and the approximation that N/O ≃ N+/O+ may introduce systematic errors greater than 25 per cent. A good compromise is to set N/He = (N2+ + N+)/He+. The N/H abundance deduced in this manner is in reasonable (≃ 25 per cent) agreement with that deduced from the standard analysis.en-USJournal Article2017-02-0819812017-06-0810.1093/mnras/197.1.1