1171 I/171 Astrographic Catalog Reference Stars T E Corbin S E Urban W H Warren Jr. NASA, NSSDC 91-10 ??? ??? 1991 1991 I/15 : FK4 Catalogue (Fricke and Kopff, 1963) I/72 : AGK3R Catalogue (Corbin, 1978) I/85 : CPC2 (2nd Cape Photographic Catalogue 1950, Nicholson et al., 1984) I/172 : IRS (International Reference Stars, Corbin, 1991) I/149 : FK5 Catalogue (Fricke et al., 1988, Veroff. ARI 32) I/219 : Cape AC Zone (-41 to -51) Reduced to ACRS (Urban & Corbin, 1995) I/222 : San Fernando AC Zone (-3 to -9) (Urban et al., 1995) I/223 : Algiers AC Zone (+4 to -2) Reduced to ACRS (Urban et al., 1995) Corbin, T.E., and Urban, S.E. 1989, in Star Catalogues: A Centennial Tribute to A. N. Vyssotsky (Schenectady, L. Davis Press), p. 59 de Vegt, Ch., Zacharias, N., Murray, C.A., and Penston, M.J. 1989, in Star Catalogues: A Centennial Tribute to A. N. Vyssotsky (Schenectady, L. Davis Press), p. 45 (Catalog: <I/85>) Schwan, H., =1988A&A...198..363S Positional data Proper motions The ACRS is an all-sky catalog of positions and proper motions that is based on the AGK3 in the north and on the newly completed second Cape Photographic Catalogue (CPC2, de Vegt et al. 1989) in the south. The astrometric data are on the system of the International Reference Stars (IRS, catalog <I/172>), compiled on B1950.0 FK4 and then transformed to J2000.0 FK5. The ACRS contains 320,111 stars, the mean positions for which were derived from a total of 1,643,783 individual input positions. The catalog is divided into two parts. Part 1 contains stars having better observational histories and, therefore, more reliable positions and proper motions, while the stars in Part 2 have poor histories and consist mostly of objects for which only two catalog positions in one or both coordinates were available for computing proper motions. For Part 1, which consists of 78 percent of the catalog, the mean errors of the proper motions in right ascension and declination are 0.47 and 0.46 seconds of arc/century (4.7 and 4.6 mas/yr), respectively. It is intended that, as more observations are accumulated for stars in Part 2, they will be migrated to Part 1. The catalog was compiled at the U.S. Naval Observatory, Washington, D.C., for purposes of performing new reductions of the Astrographic Catalogue plates. Additional details about the construction of the ACRS may be found in Corbin and Urban (1989). The data included are catalog part, ACRS number, equatorial coordinates (equinox, equator, epoch B1950.0 and J2000.0), proper motions (B1950.0 and J2000.0), original epochs, weights for right ascension and declination, and reference data such as DM numbers (BD, CD, CPD), AGK3 and CPC2 designations, and an IAU recommended ACRS identifier (based on coordinates).

PartNum Catalog Part number, '1' or '2' --- ACRS ACRS sequential number This number is between 1 and 250052 for the first part, between 500001 and 570159 for Part 2. --- RAh Hours RA, equinox=B1950, Epoch=B1950.0 h RAm Minutes RA, equinox, epoch B1950.0 min RAms Seconds RA, equinox, epoch B1950.0 ms DE- Sign Dec, equinox, epoch B1950.0 --- DEd Degrees Dec, equinox, epoch B1950.0 deg DEm Minutes Dec, equinox, epoch B1950.0 arcmin DEcs Seconds Dec, equinox, epoch B1950.0 10mas e_RAms Mean error in RA at original epoch ms e_DEcs Mean error in Dec at original epoch 10mas pmRA RA proper motion, FK4 system 0.01ms/yr pmDE DE proper motion, FK4 system 0.1mas/yr e_pmRA Mean error on pmRA 0.01ms/yr e_pmDE Mean error on pmDE 0.1mas/yr EpRA Original epoch of RA (epoch mean position) 0.001yr EpDE Original epoch of DE (epoch mean position) 0.001yr o_RAms Number of positions in RA --- o_DEcs Number of positions in DE --- w_RAms Sum of the weights in RA 0.1 w_DEcs Sum of the weights in DE 0.1 Pmag Photographic magnitude 0.01mag SpType Spectral type --- BD Bonner Durchmusterung number <I/122> --- CD Cordoba Durchmusterung number <I/114> --- CP Cape Photographic Durchmusterung <I/108> --- AGK3 AGK3 number <I/61> --- CPC2 Second Cape Photograpic Catalog <I/85> --- ACRSJ ACRS number, ACRS Jhhmmss.ssSddmmss.s This identifier is based upon the recommended IAU nomenclature (see PASP, 102, 1444, 1990). The field consists of an origin in bytes 127-130 (ACRS) and a coordinate specification in bytes 132-150 (byte 132 contains a "J" to indicate that the following coordinates are in the Julian reference system and are for the year 2000.0, the standard equinox designated for Julian system coordinates). --- RA2000h Hours RA, Equinox=J2000, Epoch=J2000 The J2000 positions are given for equinox and epoch J2000.0 on the system of FK5 after transformation of the B1950.0 values. The transformation was done using the coefficients and software package of Schwan (see Schwan 1988) and the algorithm given in the 1991 Astronomical Almanac (page B42) (foreshortening terms set to zero). (See Section 3.1 of the documentation for additional details.) h RA2000m Minutes RA, equinox, epoch J2000.0 min RA2000ms Seconds RA, equinox, epoch J2000.0 ms pmRA2000 Centennial RA proper motion, J2000.0 0.01ms/yr EpRA-J2000 Original epoch - J2000.0 in RA These values are wrong for values larger than 1 century (when the corresponding epoch is before 1900); this occurs for ACRS 86508, 240650, 533151. 0.001yr DE2000- Sign Dec, equinox, epoch J2000.0 --- DE2000d Degrees Dec, equinox, epoch J2000.0 deg DE2000m Minutes Dec, equinox, epoch J2000.0 arcmin DE2000cs Seconds Dec, equinox, epoch J2000.0 10mas pmDE2000 Centennial Dec proper motion, J2000.0 0.1mas/yr EpDE-J2000 Original epoch - J2000.0 in DE 0.001yr acrs.docASCII documentation acrs.texLaTeX documentation Gail L. Schneider SSDOO/ADC Francois Ochsenbein CDS 1995Nov29 UNKNOWN UNKNOWN * 03-Apr-1991: the completed machine-readable ACRS was transferred to the Astronomical Data Center (NASA/Goddard) * Catalogue distributed on the "Selected Astronomical Catalogs" Vol. 1 CD-ROM (1991), directory /astrom/acrs * 29-Nov-1995: data files checked, and ReadMe file standardized at CDS I_171.xml