The Abundance Gradient across the Galaxy NGC 2997

The fiber optics coupling aperture-plate system (FOCAP) of the Anglo-Australian Observatory was used to obtain low-dispersion spectra of 49 H II regions across the galaxy NGC 2997. Problems with employing fiber optics for spectrophotometry are discussed. Correlations between line ratios used as diagnostics for physical conditions and abundances in H II regions are identical to those found by McCall, Rybski, and Shields for a large number of giant H II regions in 26 galaxies. The O/H radial abundance gradient in NGC 2997 was derived using the calibration of the index ([O II] + [O III])/Hβ. The gradient and the mean metallicity of NGC 2997 are comparable to those of M51. There is significant dispersion in ([O 1I] + [O II])/Hβ and [O III]/Hβ at any given galactocentric distance. No N^+^/O^+^ gradient is observed, and the mean value of this ratio is identical to that of Galactic H II regions.