MEAN MORPHOLOGICAL TYPES OF BRIGHT GALAXIES

The revised Hubble classifications provided in the Third Reference Cat alogue of Bright Galaxies are based on nine lists and catalogues, both published and unpublished, from five observers. This paper describes the procedures that were used to combine these classifications into me an classifications including the family, variety, and stage. The best classifications in RC3 are based on large-scale photographic images ta ken with 1.5-5 m class reflectors. However, most of the types in RC3 a re based on the small-scale prints, plates, and films of the first Pal omar Sky Survey and the UK Schmidt IIIa-J Southern Sky Survey. The ove rlap between the different observers' samples allowed determination of the reliability of sky survey types and the effects of diameter and i nclination on the accuracy of these types. We find that for a typical galaxy having isophotal diameter D25 almost-equal-to 2' and inclined b y almost-equal-to 50-degrees, types T from the sky surveys have a mean error (averaged over all of the observers) of sigma(T)=0.7 step on th e numerical scale of the revised Hubble system. With the new database of classifications, we rederive the classical relations between Hubble type and integrated colors, surface brightnesses, and hydrogen index (hydrogen flux to blue light ratio) for a large sample of galaxies. We also present a table of galaxies which we consider to be representati ve examples of each type.