A catalog of relative emission line intensities observed in planetary and diffuse nebulae

A catalog of emission lines in the spectra of galactic and extragalactic planetary and diffuse nebulae is presented. The catalog gives relative emission line strengths for over 600 objects as observed by various workers over the past 35 years, and contains, as far as is known, all the significant data in the literature. In addition to giving individual relative line intensities, the catalog gives mean values of the intensities of a given line for each nebula, the individual intensities corrected for interstellar extinction, and the mean intensities also so corrected. For nebulae for which a large number of lines have been observed, a separate table gives information on the atomic transition responsible for each line.