In the early 1950's, when the first stage of the Mount Wilson and Palomar photographic survey north of = -15° was nearly complete, a plan was set out to compile existing data on types, magnitudes, and redshifts, and to obtain new data where needed For all galaxies in the Shapley-Ames catalog. From the beginning, it was our intention to restrict the revision of the original SA listings and to obtain comparable data for both hemispheres. To this end, we began observations for redshifts, morphological types, and photoelectric magnitudes at the Mount Stromlo and Siding Springs Observatories, Australia, in 1969 at the invitation of the Director, O.J. Eggen.
The observations were made by Sandage for redshifts with the Mount Stromlo 1.9-meter reflector, for types with the Uppsala Schmidt, and for photoelectric magnitudes with the Siding Springs 1-meter reflector. Observations of the northern SA galaxies still lacking redshift values were begun at Palomar in 1970. The detailed data have been published in the archival literature (Sandage 1975b, 1978). In the time since the 1969-1970 Australian expedition, galaxy types based on the Uppsala Schmidt plates have been upgraded, in many cases using large-scale reflector plates from the later Las Campanas survey already mentioned.
The present catalog is, then, a compilation of available data on redshifts, morphological types, and magnitudes for shapley-Ames galaxies, using literature sources to summer 1980. The listed types and luminosity classes are new estimates made by Sandage in a consistent way over the short period 1977-1979. The types are based on plates from Mount Wilson (W60, W100), Palomar (P200, P48), Las Campanas (C40, C100), and in a few remaining cases on the Uppsala Schmidt (UpS) at Mount Stromlo. The types are on the modified Hubble system (de Vaucouleurs, 1959; Sandage, 1961, 1975a). The luminosity classes generally follow van den Bergh's (1960a, b, c) precepts, but are on an internally consistent system defined here by the present listings and illustrated with type examples in the reproductions in part V of this volume.
Redshifts are from the literature sources listed in Part VII. The values have been combined and weighted as discussed on pages 10-11.
The magnitudes are on the BT system of the Second Reference Catalog (RC2: de Vaucouleurs et al., 1977), obtained by reducing all new data to this system in the manner described on pages 6-8.
As an aid in using the present catalog, we have binned the 1246 listed galaxies separately into the various morphological types in the tables in part III. We believe that some of these types, and hence this particular binning, will change as better plate material becomes available, but the listing is meant as an aid in planning various observing programs based on knowledge of types as it existed in 1979.