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Multivariate data have been collected as part of an effort to develop a new classification system for spiral galaxies, one which is not necessarily based on subjective morphological properties. A sample of 492 moderately bright northern Sa and Sc spirals was chosen for future statistical analysis. New observations were made at 20 and 21 cm; the latter data are described in detail here. IRAS fluxes were obtained from archival data. Finally, new estimates of arm pattern randomness and of local environmental harshness were compiled for most sample objects.
C. Magri (Thu,) studied this question.