A Catalogue of Rich Clusters of Galaxies Abell, G. O., Corwin, H. G. Jr., and Olowin, R. P. 1988, Astrophys. J. Suppl., submitted. The content of the Abell Catalogue data files is identical to the tables published in Ap. J. Suppl. Series. There are four data files: nabell.fin: final northern Abell catalogue rich.fin: final southern Abell catalogue poor.fin: supplementary southern Abell catalogue sabell.fin northern Abell clusters found during the southern survey and all have exactly the same format. An example with column headings is given below. Note that the northern Abell catalogue does not list xcen, ycen, Abell type, m1, m3, m10, previous listings, or number of plates and observers. The northern catalogue has also had all known errors corrected (Struble and Rood (1987ApJS...63..543S), Leir (1976, M.Sc. Thesis, Toronto Univ.) as reported by Struble and Rood (1987ApJS...63..543S), and Corwin 1972 unpublished). EXPLANATION OF THE TABLES: Column Contents Abell Running number ("Abell" number) in order of right ascension for 1855 as listed by Abell (1958ApJS....3..211A) for the northern clusters (1 to 2712) and in order of right ascension for 1950 for the southern clusters (2713 to 4076). The supplementary southern clusters are numbered from S1 to S1174. Position Right Ascension and Declination for 1950 of the apparent cluster (1950) center. When the cluster was found in more than one field, a mean position is listed. Abell and Corwin used overlays positioned with respect to SAO stars to estimate the position, while Olowin calculated positions from his measured rectangular coordinates. Thus, Olowin's positions were given double weight when means were taken. Field The Southern Sky Survey Field number in which the cluster is located. For clusters found in two or more fields, the field given is the one in which the cluster is closest to the plate center. xcen, ycen Rectangular coordinates in millimeters of the apparent cluster center, referred to the CENTER of the Southern Sky Survey Field given in the previous column. The field centers are defined by the crosses near the edges of the plates. The positive x direction is to the east (left) and the positive y direction is to the north (top). These are in the same sense as the rectangular coordinates given by Lauberts (1983, Cat. VII/34) in the ESO/Uppsala Catalogue, and are listed to facilitate location of the cluster on the 5 x 5-degree ESO 1.0-m Schmidt portion of the Southern Sky Survey. Abell and Corwin measured rectangular coordinates from the left and bottom edges of the plates, so the xcen and ycen from their data are calculated assuming that the plate center is 164 millimeters from the left and bottom crosses on the plates (they also measured the crosses). Olowin referred his rectangular coordinates directly to the plate center as defined by the crosses, so no transformation is necessary for his data. Abell Type Cluster classification in Abell's system: I = irregular, R = regular, IR and RI = intermediate. ":" indicates a mean type with differences between estimates of two steps, or an uncertain type estimate; "?" indicates a mean type with differences between estimates of three steps, or a questionable type estimate. Bautz-Morgan Classification in the Bautz-Morgan system (Bautz and Morgan Type 1970ApJ...162L.149B). ":" indicates a mean type with differences between estimates of two steps, or an uncertain type estimate; "?" indicates a mean type with differences between estimates of three or more steps, or a questionable type estimate. For the northern Abell catalogue, these types are primarily from Leir and van den Bergh (1977ApJS...34..381L). Other sources for the northern catalogue are Bautz and Morgan (1970ApJ...162L.149B), Bautz (1972AJ.....77....1B), Corwin (1974AJ.....79.1356C), Kristian et al. (1978ApJ...221..383K), Sandage et al. (1976ApJ...205..688S), and White (1978ApJ...226..591W). Count Number of cluster members between m3 and m3+2, corrected for background contamination using the "universal" luminosity function from Rainey (1976, Ph.D. Univ. California, Los Angeles). The southern counts are corrected to the system of the northern catalogue (see text). m1 Weighted mean total V magnitude estimate for the first-ranked cluster member. NO GALACTIC EXTINCTION CORRECTION HAS BEEN APPLIED. ":" indicates a mean magnitude with a standard deviation of more than +-0.5 mag, or an uncertain magnitude estimate. "?" indicates a mean magnitude with a standard deviation of more than +-1.0 mag, or a questionable magnitude estimate. "*" indicates that the magnitude estimate is for a known or probable foreground object. m3 Weighted mean total V magnitude estimate for the third-ranked cluster member, again UNCORRECTED for galactic extinction. Uncertainty symbols as for m1. m10 Weighted mean total V magnitude estimate for the tenth-ranked cluster member, again UNCORRECTED for galactic extinction. Uncertainty symbols as for m1 and m3. Position RA and Dec of the apparent cluster center precessed to the (2000) equinox of 2000. Previous Sources of previous listings: Listings B = Braid and MacGillivray (1978MNRAS.182..241B), D = Duus and Newell (1977ApJS...35..209D), d = Dressler (1980ApJS...42..565D, Cat. VII/174), K = Klemola (1969AJ.....74..804K), O = Olowin (1987, in IAU Symposium 124, p. 331), Q = Quintana and White (1980BAAS...12..834Q and private communication), R = Rose (1976A&AS...23..109R), S = Sersic (1974Ap&SS..28..365S), and s = Snow (970AJ.....75..237S). Even though all questionable cases of cross identification were checked on the Southern Sky Survey, there remain a few uncertain cases. These are given in the Notes to the Catalogue. xll, yll Rectangular coordinates of the apparent cluster center, referred to the south-east (lower left) edge of the Southern Sky Survey Field given in the first line. The field edges are defined by the crosses near the edges of the plates; thus, it is possible for these coordinates to be negative. For the northern Abell catalogue, these coordinates are from Rood and Sastry (1971PASP...83..313R). Olowin's data were transformed assuming that the plate center is 164 millimeters from the crosses. l and b Galactic coordinates of the apparent cluster centers, calculated from the 1950 equatorial coordinates. z Cluster redshift from the lists by Struble and Rood (1987ApJS...63..555S, northern Abell clusters), Huchra's 1986 collection of published redshifts (Huchra, private communication), Fairall (1985, Cape Town Univ., Astronomy Department Publ. 7), Corwin (1981, Ph.D. Thesis, Univ. Edinburgh; see also Corwin and Emerson 1982MNRAS.200..621C), Couch and Newell (1984ApJS...56..143C and private communication), Noonan (1981ApJS...45..613N), and Spinrad (private communication). The redshift is in parentheses if it is more than 0.3 dex from the expected redshift for the cluster's m10. Redshifts from Huchra's list and from Fairall (1985, Cape Town Univ. Publ. 7) were determined by selecting all galaxies with known redshifts within one Abell radius of the cluster center, rejecting discordant redshifts, and averaging the remainder. R Richness class as defined by Abell (1958ApJS....3..211A). For the northern Abell catalogue, this is Abell's original richness class. D Distance class corresponding to Abell's (1958ApJS....3..211A) criteria. For the northern Abell catalogue, this is Abell's original distance class from his m10. For the southern catalogue, these are from the m10A's listed in the next column. m10A Magnitude for the tenth-ranked cluster member in Abell's (1958ApJS....3..211A) system, corrected for galactic extinction following Abell's formula. For the northern Abell catalogue, this is Abell's original magnitude. For the southern catalogue, these were transformed from the m10 on the first line (see text). Number and Number of fields in which the cluster was found, and the Observers observer's initial (A = Abell, C = Corwin, O = Olowin).