Sources of Accurate Positions for Nonstellar Objects N.B. Quoted standard deviations are usually internal errors, exclusive of systematic errors. There are thousands of examples of positions for the same object differing by much more than the quoted errors. 2MSP 2MASS Point Source Catalog, 2000. On-line version via VizieR. *Standard deviation 0.18 arcsec. There are far fewer problems with the point source positions than there are with the extended source positions. 2MSX 2MASS Extended Source Catalog, 2003. (Some positions from the 1st or 2nd Incremental Releases, 1999 and 2000, via NED). *Standard deviation 0.30 arcsec, but much larger accidental errors can occur in the Incremental Releases. I checked all of these before entering them here. The problems (due to edge-of-scan effects) are largely overcome in the Full-Sky release of 2003, but some remain. AA Arthur Auwers, AN 58, 369, 1862; micrometric observations, re-reduced. *Standard deviation about 2 arcsec at a guess. AAS A.A. Schoenmaker, quoted in dBW and vdK2,3 (which see; also see van Herk and Schoenmaker, IAU Circular 2334, 1971 and A&A 17, 146, 1971 for repeat of N5055). Optical positions for a few bright galaxies. *Standard deviation about 0.5 arcsec. AC R. W. Argyle and E. D. Clements, Observatory 110, 93, 1990. N = 32 *Standard deviation about 0.2 arcsec. AC22 AC 2000.2. Stars; and a few planetaries, courtesy Brian Skiff. Proper motion almost always ignored. *Standard deviation around 0.2-0.3 arcsec at B1950.0. ACR R. C. Stone, J. R. Pier, and D. G. Monet, AJ 118, 2488, 1999. Astrometric Calibration Regions around the celestial equator. A few galaxies picked up among the 1.2 million stars. These are tightly tied to the ICRS. *Standard deviation around 0.03 arcsec (that is not a typo: 0.03"!) AE R. W. Argyle and P. Eldridge, MNRAS 243, 504, 1990. Seyfert galaxies. N = 72 *Standard deviation about 0.15 arcsec. AGK2 A. Kopff and J. Peters. AGK2. Astron. Rechen-Inst. Veroff. 16, No. 71. Positions for objects that can be fairly represented by stars. *Standard deviation about 0.3 arcsec (but with systematic errors). AGK3 AGK3 (check SIMBAD or VizieR for the complete reference). Positions for stellar objects. *Standard deviation about 0.3 arcsec (but with systematic errors). AH Brent A. Archinal and Steven J. Hynes. "Star Clusters", 2003 Willmann-Bell, Richmond, VA. Positions for Galactic, LMC, SMC, M31, and Fornax open and globular clusters, precessed from J2000.0. *Standard deviation varies, depending on cluster size and position source. AK A. N. Argue and C. M. Kenworthy, MNRAS 160, 197, 1972. NGC 1275. N = 1 *Standard deviation about 0.2 arcsec. AK90 O.B. Aaquist and S. Kwok. A&AS 84, 229, 1990. Position for NGC 6807 pulled in by B.A. Skiff. *Standard deviation a few arcsec at a guess. AM H.C. Arp and B.F. Madore. "Catalogue of Southern Peculiar Galaxies and Associations," Cambridge U. Press, 1987. *Standard deviation around 15-20 arcsec. AMo R.W. Argyle and L.V. Morrison, IAUC 5976, 1994. Offsets (9"w, 7"n; see Treffers etal. IAUC 5946) from SN 1994D in NGC 4526 for nucleus. SN pos is 12 31 29.945 +07 58 36.87 (n=18) +-0.06 arcsec. *Standard deviation about an arcsec; depends on offset. APM S. Maddox et al, MNRAS 243, 692, 1990. APM Galaxy Catalogue, 1996 version. Selected galaxies only. *Standard deviation 0.5 arcsec for small galaxies, up to 8-10 arcsec for large galaxies. Use 3 arcsec for the time being. APMN Northern APM scans from POSS1 copy plates. Seems to be free from the systematic errors that plague the southern APM positions. *Standard deviation for small galaxies 0.2 arcsec, probably around 1-2 arcsec for large ones. APMb J. Loveday et al, MNRAS 278, 1025, 1996. APM Bright Galaxy Catalogue. Selected galaxies only. Many galaxy images are contaminated by superposed star images, and many others have just plain wrong positions. *Standard deviation around 3 arcsec. Occasional much larger errors are weeded out. APMn A. Naim et al, MNRAS 274, 1107, 1995. 830+- galaxies in the south- equatorial zone. Same problems as the APM Bright Galaxy Catalogue (APMb here, which see), though superposed stars are less frequent. *Standard deviation around 8-10 arcsec. AO Aoki et al (1991, PASJ 43, 775; pos for IR nucleus of NGC 891) *Standard deviation a few arcsec. AR R. J. Allen and E. Raimond, A&A 19, 317, 1972. Maffei 2. N = 1 *Standard deviation 2 arcsec. ASec A. Secchi. AN 66, 11, 1866. About a dozen objects found by Brother Ferraro at College Roman, most now unidentifiable. Nominal positions. *Standard deviation meaningless. Ames A. Ames, HA 88, No. 1, 1930. Virgo Cluster survey on four Bruce refractor plates. Only positions that Ames measured herself used here. She took most NGC/IC positions from the NGC/IC itself. *Standard deviation 20 arcsec at a guess. Bar E.E. Barnard, various publications. Micrometric observations, re-reduced w.r.t. modern comparison positions when possible, precessed otherwise. (See also EEB, below). *Standard deviation a few arcsec. Bax J. Baxendell. Nominal position for NGC 7088, a non-existent nebula. *Standard deviation meaningless. Be L. Becker, Annals of the Edinburgh Observatory No. 1, page 1, 1902. Meridian circle observations. *Standard deviation around 5 arcsec at a guess. Beck S.C. Beck et al. ApJ 457, 610, 1996. 2-cm and H-alpha peaks for NGC 5253; astrometry based on GSC stars. *Standard deviation 1-2 arcsec in both coordinates. Bids Bidschof, AN 3520. Micrometric measurements at Vienna Obs. Precessed from 1890.0. *Standard deviation around 2 arcsec. Big G. Bigourdan, visual micrometric measurements (1884 - 1907) reduced by me w.r.t. SAO, AGK3, GSC, or AC positions, taking proper motion into account when possible. *Standard deviation varies, usually about 2 arcsec, but is larger for objects with poorly-defined or faint nuclei. Bige G. Bigourdan, estimated offset. *Standard deviation anywhere from 3 to 30 arcsec. Bign Bigourdan's nominal position for objects not found by me. *Standard deviation meaningless in this case. Bond G. P. Bond, AN 1453. Micrometric observations with the 16-inch Harvard refractor, c. 1850s. Most are stars. *Standard deviation around 20 arcsec at a guess. Bord M. Rapaport et al. A&A 376, 325, 2001. Bordeaux meridian circle positions for PNe, extracted by Brian Skiff. *Standard deviation around 0.15 arcsec at a guess. BAA Brent A. Archinal, private communication (but also see source AH). Open clusters. *Standard deviation 5-30 arcsec depending on cluster size. BASm B. Skiff, means from several different sources, usually for planetaries. *Standard deviation around 1-2 arcsec. BC R. Buta and H. Corwin, Ap. J. Suppl. 62, 255, 1986. Means of several sources (calculated by me). Hercules Cluster. N = 35 *Standard deviation better than 1 arcsec. BCG E.J. Barton, R.R. De Carvalho, and M.J. Geller. AJ 116, 1573, 1998. About 500 galaxies in or near compact groups. *Standard deviation 2-3 arcsec. BCGP Barbieri, C., Capaccioli, M., Ganz, R., and Pinto, G. AJ 77, 444, 1972. Radio sources. *Standard deviation about 0.4 arcsec. BI W.A. Baan and J.A. Irwin. ApJ 446, 602, 1995. 1412.1 and 1655.2 MHz observations of the unresolved nuclear source in NGC 3079. *Standard deviation around 0.3-0.4 arcsec. BJM B.J. McNamara. PASP, 83, 491, 1971. Crab pulsar from Lick 36-inch plates. *Standard deviation around 0.1 arcsec. BPP L. Basso, G. Palumbo, R. Primavera, G. Vettolani, and M. Vigotti. A&AS 83, 569, 1990. CGCG galaxies, Paper 4 (see VPS). Paper copies of microfiche scanned, proofed. *Standard deviation depends on size of galaxy, varies from 1 arcsec to 5 arcsec. BSV Brian Skiff, private communication. Open clusters and central stars of planetaries, measured using SkyView, precessed from J2000.0. *Standard deviation depends on size of object. For planetaries, it is around 2 arcsec; for small compact clusters, around 5 arcsec; for large scattered clusters, around an arcmin. BSa B. Santiago, private communication. ESGC galaxies, measured with an overlay. N = 20 *Standard deviation about 10 arcsec. BSc E. Bica and H. Schmitt, ApJS 110, 41, 1995. SMC clusters and nebulae, from ESO IIIa-F sky survey films. *Standard deviation about 10 arcsec. BTC Bordeaux Transit Circle. See 2001A&A...376..325R. Courtesy Brian Skiff; a few planetaries. *Standard deviation 0.1 arcsec at a guess (I obviously haven't seen the paper yet.) CMT D.W. Evans, M.J. Irwin, and L. Helmer. A&A 395, 347, 2002. Carlsberg Meridian Transit CCD drift scans in the +-3 deg equatorial belt. The galaxies are usually in the "reject" file, but their positions nevertheless have very small errors. This will eventually extend north to +30 deg. *Standard deviation "about 0.035 arcsec." Cer V. Cerulli, AN 139, 47, 1895; NGC 5898, 5903 micrometrically measured, precessed from equinox 1895. *Standard deviation probably 2-3 arcsec Cope Ralph Copeland, found with LdR's 72-inch. Adopted only for missing objects. *Standard deviation meaningless. CB2,CB2o J.J. Condon and J.J. Broderick. AJ 102, 1663, 1991. 6-cm and optical positions for galaxies identified with IRAS sources. *Standard deviations: less than 1 arcsec for 6-cm, 0.5 arcsec for optical positions given to 0.1 arcsec, 3-5 arcsec for optical given to 1 arcsec. CBF R. Chandar, L. Bianchi, H.C. Ford. ApJS 122, 431, 1999. M33 on HST WFPC2 frame. *Standard deviation around 0.2-0.3 arcsec. CCA W. Cotton, J.J. Condon, E. Arbizzani. ApJS, December 1999. All UGC galaxies, from DSS. NGC/IC identifications are mine. *Standard deviation: 1.2 arcsec (though CCA added in an additional error as a function of diameter as well; I've included their nominal error as a note). CCBD J.J. Condon, M.A. Condon, J.J. Broderick, and M.M. Davis. AJ 88, 20, 1983. Optical positions for flat-spectrum radio sources. Four NGC/IC objects included. *Standard deviations: 1 arcsec. CCR,CCO J.J. Condon, M.A. Condon, G. Gisler, and J.J. Puschell. ApJ 252, 102, 1982. 6- or 21-cm positions (CCR), or optical positions (CCO) for bright spirals. *Standard deviations: 1 arcsec (optical), "smaller than 1 arcsec" (radio). CDC P.C. Crane, J.R. Dickel, and J.J. Cowan, ApJ 390, L9, 1992. 3.6 cm position for the nucleus of M31. *Standard deviation 0.4 arcsec. CFB,CFBo J.J. Condon, D.T. Frayer, and J.J. Broderick. AJ 101, 362, 1991. 6-cm and optical positions for UGC galaxies which are strong radio sources. *Standard deviations: less than 1 arcsec for 6-cm, 0.5 arcsec for optical positions given to 0.1 arcsec, 3-5 arcsec for optical given to 1 arcsec. CK J. Condon and D.L. Kaplan, ApJS 117, 361, 1998. Optical positions of planetary nebulae measured on DSS. *Standard deviation 1-2 arcsec for stellar planetaries, 5-10 arcsec for larger objects. CP C. Pollas, Observatoire de la Cote d'Azur, IAU Circulars Nos. 5076, 5141, 5147, 5421; parent galaxies of SNe. *Standard deviation probably 1-2 arcsec CSD E. Corbelli, E. E. Salpeter, and J. M. Dickey, ApJ 370, 49, 1991. Positions for galaxies in two rich clusters, including Abell 400. *Standard deviation a few arcsec. CSP C. S. Pierce, Harvard Annals, Vol 8, Part 1. Used only when the object is not found (e.g. NGC 1170). *Standard deviation meaningless. CW Carl Wirtz, Strassburg Annals, 1911. Precessed from 1900, or occasionally re-reduced from the original micrometric offsets. *Standard deviation a few arcsec. (CW1 Identification by Corwin, position from Wolf, List 1 (MW1).) This source replaced by MW1. *Standard deviation around 3-5 arcsec. d'A Heinrich d'Arrest, 1867. Observed positions precessed from 1861. Usually included only for nebulae not found. *Standard deviation around an arcmin, but meaningless for objects not found. dBW A.G. de Bruyn and A.G. Willis. A&A 33, 351, 1974. 6-cm positions for NGC 2782 and NGC 4151 (RA's only, not included here, for N1068, N3227, and N7469). *Standard deviation 1 arcsec or better. Den Denning, private communication to Dreyer; taken from NGC. This source will be replaced; positions are place-holders for now. *Standard deviation around 2-3 arcmin. DAD D. A. Dale, AJ, in press. DSS positions for galaxies in clusters. *Standard deviation around 1 arcsec. DC L. L. Dressel and J. J. Condon, Ap. J. Suppl. 31, 187, 1976. *Standard deviation around 4 arcsec. DDB D.D. Balam. IAUC 6427. Positions for parent galaxies of SNe. *Standard deviation better than 0.5 arcsec. DFOT M. Doi, M. Fukugita, S. Okamura, and K. Tarusawa. ApJS 97, 77, 1995. Galaxies brighter than B = 16 within 5 degrees of the Coma Cluster. *Standard deviation around 1 arcsec. DJS[o|r] D.J. Saikia et al. MNRAS 245, 397, 1990. Optical and radio positions for nuclear hot spots in NGC 1808. *Standard deviation 0.5 arcsec. DKM1 D. K. Milne, A.J. 78, 239, 1973. Planetaries. *Standard deviation 6-8 arcsec. DKM2 D. K. Milne, A.J. 81, 753, 1976. Planetaries. *Standard deviation 6-8 arcsec. DLW D. L. Welch, AJ 101, 538, 1991. SMC clusters. *Standard deviation 5 arcsec. DM S. Djorgovski and G. Meylan, 1993, in Structure and Dynamics of Globular Clusters, ASP Conference Series No. 50, ed. Djorgovski, S. and Meylan, G., ASP (San Francisco), p. 325. Globulars. *Standard deviation a few arcsec. DS Delisle Stewart, HA 60. 677 nebulae found on 24-inch Bruce reflector plates taken at Arequipa, Peru. Used only when the nebula is not found. Given to 0.1 minute and 1 arcmin in HA 60. *Standard deviation meaningless. DSFA M. Cragin, J. Lucyk, B. Rappaport. The Deep Sky Field Guide to Uranometria 2000.0, 1993, Willmann-Bell (Richmond, VA), quoted by B.A. Archinal in Star Clusters (see source AH), for NGC 1881. *Standard deviation unknown, probably an arcminute or so. DWFo M. J. Drinkwater, R. L. Webster, P. J. Francis, J. J. Condon, S. L. Ellison, D. L. Jauncey, J. Lovell, B. A. Peterson, and A. Savage, MNRAS 284, 85, 1997. Optical positions for Parkes radio sources, taken from the COSMOS/UKST Southern Sky Catalogue, corrected for systematic plate-to-plate errors; or from APM scans of the POSS1. *Standard deviation 0.8 arcsec. DWFr M. J. Drinkwater, R. L. Webster, P. J. Francis, J. J. Condon, S. L. Ellison, D. L. Jauncey, J. Lovell, B. A. Peterson, and A. Savage, MNRAS 284, 85, 1997. Radio positions for Parkes radio sources, observed at the VLA or at the ATCA. *Standard deviation about 0.3 - 0.5 arcsec. dEn d'Engelhardt, monograph. Micrometric positions for a few IC objects, precessed from 1885.0. *Standard deviation 3-5 arcsec at a guess. ECP Edward C. Pickering, Harvard Circular No. 5. Miscellaneous positions, usually measured on Harvard plates. *Standard deviation a few arcsec. EDC E. D. Clements, MNRAS 197, 829, 1981. Seyfert Galaxies. N = 14 *Standard deviation around 0.15 arcsec. EEB E.E. Barnard, IC positions precessed; used for objects not found in any of Barnard's published papers. Some positions are exact and obviously micrometrically measured, but most are clearly estimates. I've found one (IC 5259) that is 2.5 min off in RA, and another (IC 5366) that may be 2 degrees off. *Standard deviation varies, but take an arcmin. EHDS E. Hummel and D.J. Saikia, A&A 249, 43, 1991. 1.49 GHz and 4.86 GHz positions for NGC 4388 and NGC 4438. *Standard deviation 0.5 arcsec at a guess. EHo Eric Holmberg, Double Galaxy Catalogue, 1937. Delta RA, delta Dec from main galaxy to companions. *Standard deviation about 10 arcsec. EJS E. J. Shaya, et al. A.J. 111, 2212, 1996. N = 1. NGC 1316 *Standard deviation probably 0.5 arcsec or so. En R. Engelmann, AN 104, 193, 1883. Meridian circle observations. Precessed from equinox 1870.0. *Standard deviation around 3-5 arcsec; there is probably a systematic offset. ESO Andris Lauberts, The ESO/Uppsala Survey of the Quick B Atlas of the Southern Sky (Garching: ESO), 1982. This reference is being replaced by the more explicit ESOB as I find them. *Standard deviation about 5-6 arcsec. ESOB Andris Lauberts, The ESO/Uppsala Survey of the Quick B Atlas of the Southern Sky (Garching: ESO), 1982. *Standard deviation about 5-6 arcsec. ESOLV A. Lauberts and E. Valentijn, Surface Photometry of the ESO/Uppsala Galaxies (Garching: ESO), 1989. Positions revised from ESO, newly measured, or offset from ESO-B position. *Standard deviation about 6-8 arcsec. EWSo R.D. Ekers, J.V. Wall, P.A. Shaver, W.M. Goss, R.A.E. Fosbury, I.J. Danziger, A.F.M. Moorwood, D.F. Malin, A.S. Monk, and J.A. Ekers. MNRAS 236, 737, 1989. Optical positions for radio galaxies. *Standard deviation 1-1.5 arcsec. EWSr R.D. Ekers, J.V. Wall, P.A. Shaver, W.M. Goss, R.A.E. Fosbury, I.J. Danziger, A.F.M. Moorwood, D.F. Malin, A.S. Monk, and J.A. Ekers. MNRAS 236, 737, 1989. 6.1-cm positions for radio galaxies. *Standard deviation 0.3-0.5 arcsec. FAB F.A. Bellamy. MN 64, 662, 1904. Position for IC 4996, derived from an approximate mean for positions of 103 stars in an area about 15 arcmin across. *Standard deviation 2-3 arcmin. FAST FASTT transit circle. See 1999AJ....118.2488S. Courtesy of Brian Skiff; a few planetaries. *Standard deviation 0.1 arcsec at a guess (I obviously haven't seen the paper yet). FBP C.B. Foltz, B.M. Peterson, and T.A. Boroson. Astron. J. 85, 1328, 1980. Markarian 701-797. *Standard deviation 1-2 arcsec. FBi F. Bidschof. (Ann. K. K. Univ.-Sternw. Wein, 14, 1, 1900). Micrometric measurements, precessed from 1897.0. *Standard deviation 2-3 arcsec at a guess. FC H. Ferguson, A.J. 98, 367, 1989, from hand measures of Las Campanas 2.5-m plate. Fornax Cluster. (This and sources FSn and FSs replace source HF.) *Standard deviation 20 arcsec at a guess. FCJL H.C. Ford, P.C. Crane, G.H. Jacoby, D.G. Lawrie, and J.M. van der Hulst. ApJ 293, 132, 1985. 6 and 20-cm observations of NGC 5194. *Standard deviation 0.04 arcsec. FGLM E.B. Fomalont, W.M. Goss, A.G. Lyme, R.N. Manchester. MN 210, 113, 1984. Crab pulsar from VLA observations. *Standard deviation 0.1 arcsec FK5 Fifth Fundamental Catalogue. Positions for a few bright stars. *Standard deviation 0.1 arcsec FKL K.C. Freeman, B. Karlsson, G. Lynga, J.F. Burrell, H. van Woerden, and W.M. Goss. A&A 55, 445, 1977. Optical position for the Circinus Galaxy. FMu Frank Muller, micrometric measurements, re-reduced using modern positions for comparison stars. FPB C.B. Foltz, B.M. Peterson, and T.A. Boroson. AJ 85, 1328, 1980. FSn H. Ferguson, A.J. 98, 367, 1989, from unsaturated PDS scans of IIIa-J plate. Fornax Cluster. *Standard deviation 3 arcsec. FSs H. Ferguson, A.J. 98, 367, 1989, from saturated PDS scans of IIIa-J plate. Fornax Cluster. *Standard deviation 10 arcsec at a guess. FT J.R. Fisher and R.B. Tully. (A&A 44, 151, 1975). DDO galaxies. *Standard deviation 10 arcsec. Fin W. H. Finlay. A few nebulae found with the 7-inch refractor at Cape Town in the 1890's. Positions reported only if the objects are not found. *Standard deviation meaningless. Fr R. H. Frost, in Harvard Annals 60. Used only when the object is not found. *Standard deviation meaningless. GC J.R. Glanfield and M.J. Cameron. Aust. J. Phys. 20, 613, 1967. 139 Bright galaxies south of +20 degrees. *Standard deviation 15 arcsec. GD Glen Deen, private communication. *Standard deviation 5-6 arcsec at a guess. GDC [Unknown source]. Position for IC 2373 = UGC 04409. GGH N.A. Grogin, M.J. Geller, and J.P. Huchra. ApJS 119, 277, 1998. Galaxies within 15 degrees of 3C 273, most from CGCG. *Standard deviation 1-2 arcsec. GGN S. Garcia-Burillo, M. Guelin, and N. Neininger, IRAM preprint No. 416, 1996 (to appear in A&A). Kinematic center of NGC 5907 from high-resolution CO(1-0) observations. *Standard deviation on the order of 1 arcsec. GH Gallouet and Heidmann (A&A Suppl. 3, 325, 1971). RC1 galaxies, -2deg to +26deg. *Standard deviation 4-6 arcsec. GHD1 Gallouet, Heidmann, and Dampierre (A&A Suppl. 12, 89, 1973). RC1 galaxies, +26deg to +90deg. *Standard deviation 4-6 arcsec. GHD2 Gallouet, Heidmann, and Dampierre (A&A Suppl. 19, 1, 1975). RC1 galaxies, -2deg to -33deg. *Standard deviation 4-6 arcsec. GJM L.J. Greenhill, D.R. Jiang, J.M. Moran, M.J. Reid, K.-Y. Lo, and M.J. Claussen. ApJ 440, 619, 1995. Water maser in the nucleus of NGC 4258. *Standard deviation 0.1 arcsec. GMH L.J. Greenhill, J.M. Moran, and J.R. Herrnstein. ApJ 481, L23, 1997. VLBA position for the water maser in the nucleus of NGC 4945. *Standard deviation 0.1 arcsec. GMKM P. Goudfrooij, J. Mack, M. Kissler-Patig, G. Meylan, and D. Minniti. MNRAS, 322, 643, 2001. Optical position for NGC 1316, "derived from archival HST/WFPC2 images". *Standard deviation on the order of 0.3 arcsec at a guess. GMS G. M. Searle, micrometric observations in HA 60. Re-reduced when offsets given. *Standard deviation about 2 arcsec at a guess. GPB R.E. Goodson, J.J. Palimaka, and A.H. Bridle. AJ 84, 1111, 1979. Radio sources and a few companions. *Standard deviation about 0.4 arcsec. GRP L. Gregorini, H.R. de Ruiter, P. Parma, E.M. Sadler, G. Vettolani, and R.D. Ekers. A&AS 106, 1, 1994. Optical positions for "dumbbell" galaxies in rich southern clusters. *Standard deviation about 2 arcsec. GSC Guide Star Catalog, V1.1 (Space Telescope Science Institute, 1991). *Standard deviation 1-2 arcsec. The final digits (0.01 sec, 0.1 arcsec are not significant, but are carried for roundoff protection. GSC2 Guide Star Catalog, V2.2 (Space Telescope Science Institute, 2001). *Standard deviation 0.2-0.3 arcsec for stellar images. GSCm Mean of "several" objects from Guide Star Catalog, V1.1 (STScI, 1991), typically for double or multiple stars. *Standard deviation 2-10 arcsec, depending on separation. GSCA GSC-ACT. Re-reduction of GSC 1.1 by Bill Gray using ACT stars as the reference frame. Also called GSC "1.3" by CDS. *Standard deviation about 0.3-0.4 arcsec for stellar objects. GSCM Dan Moaz, et al. 1996ApJS..107..215M. "An Atlas of HST UV Images of Nearby Galaxies." From GASP images; intensity weighted centroids, similar to GSC. N = 110 *Standard deviation 1-2 arcsec, though occasional accidental errors due to distorted isophotes can be up to 5 arcsec. GSCT D.A. Turnshek, et al. A.J. 99, 1243, 1990. 3 globulars, 2 galaxies, from the Guide Star Catalog "using the Center of Gravity centroiding method, mean error 1 arcsec." For stellar objects, yes, but not for these five "non-stellar" objects. *Standard deviation 5-10 arcsec. GSWr/o R.D. Gehrz, R.A. Sramek, and D.W. Weedman. ApJ 267, 551, 1983. 6 and 20-cm observations of NGC 3690e and w (incorrectly called NGC 3690 and IC 694), and H-alpha peaks (read from their maps). *Standard deviation better than 0.3 arcsec for the radio observations, 0.5 for the optical. GVW G.V. Williams. IAUC 6427. Positions for nuclei of SN parent galaxies. *Standard deviation better than 0.5 arcsec. GYSB P. Guhathakurta, B. Yanny, D.P. Schneider, and J.N. Bahcall. AJ 111, 267, 1996. M15 *Standard deviation about 0.3 arcsec. GrV G. Grueff and M. Vigotti. A&AS 6, 1, 1972. Positions for B2 radio sources identified with galaxies. *Standard deviation 2-3 arcsec. Hart E. Hartwig, AN 112, 407, 1885. Five new nebulae found with the 18-inch refractor at Strassburg, micrometrically measured. *Standard deviation about 5 arcsec. Harv Harvard Annals, Vol. 8. Nominal position for NGC 3097, now lost. *Standard deviation meaningless. Hee D.S. Heeshan. ApJ 151, L135, 1968. NGC 1052. *Standard deviation around 0.5 arcsec. Hu Edwin Hubble, Publ. Yerkes Obs. 4, Part II, 1917. Photographic positions, refered to AGK1 stars, precessed. *Standard deviation about 5 arcsec. HC My own measurements with an engineering scale, astrometrically reduced, generally on the PSS prints, sometimes from the IIIa-J SSS films. *Standard deviation about 5 arcsec. HC2m My own measurements using IPAC Skyview with 2MASS J-band images for galaxy nuclei (intensity-weighted centroids using Skyview's "examine" command). Most of the nuclei are stellar in the 2MASS frames. *Standard deviation 0.15 arcsec internal, in both RA and Dec, from measurements of Tycho-2 stars in the same 2MASS frames. HCds My own measurements using IPAC Skyview with DSS images downloaded from STScI or GSFC's SkyView. Intensity weighted centroids using Skyview "examine" command are given to 0.01 sec and 0.1 sec, positions from "pick" command, or means, are given to 0.1 sec and 1 sec. *Standard deviation 0.8 arcsecond for well-defined images, 2-5 arcsec for large overexposed images. The 0.01 seconds and 0.1 arcsec digits are barely significant, and are carried as roundoff protection. HCe My own measurements for very large diffuse nebulae. Positions are the estimated center of gravity of the image on the PSS, and are adequate for identification. *Standard deviation about 0.1 degree. HCht My own measurements from HST images. Details in Notes for each object. *Standard deviation about 0.1 arcsec, dominated by systematic error. HChw My own measurements in 1970-71 for NGC/IC objects on the Hodge-Wright LMC Atlas charts. *Standard deviation about 10 arcsec. HCm Means from several sources, reduced by me. *Standard deviation usually better than 1 arc second, but depends on sources used and centering. HCo My own measurements, offset from GSC stars unless noted, generally on the PSS prints, sometimes on the IIIa-J SSS films. *Standard deviation around 2 arcsec if the GSC star/galaxy is within 2 arcmin of the object, around 4-5 arcsec for larger distances. HCos My own measurements, offset from SAO stars, generally on the PSS prints, sometimes on the IIIa-J SSS films. Most are now replaced or rejected. *Standard deviation is around 10-15 arcsec; larger accidental errors are not uncommon. HCp My own measurements using the Edinburgh XY machine, astrometrically reduced w.r.t. SAO stars. Indus Supercluster galaxies. *Standard deviation better than 1 arc second, but subject to systematic errors in the SAO positions. HCns My own measurements using IPAC Skyview with NEAT/SkyMorph images downloaded from GSFC's SkyView. See HCds for more info. *Standard deviation unknown, but under one arcsec. HCrs My own measurements using RealSky images. RealSkyView positions are given to 0.1 sec and 1 arcsec, Skyview positions to 0.01 sec and 0.1 arcsec. Reference system is AGK3. *Standard deviation around 1-2 arcsecond for small galaxies, 2-3 arcsec for larger or brighter ones using RealSkyView. Probably a bit better for positions from Skyview. HCsc My own measurements on SuperCOSMOS images. *Standard deviation probably 0.3 to 0.4 arcsec from comparison with my 2MASS measurements (source HC2m, which see). HCsd My own measurements using GSFC SkyView with SDSS images. *Standard deviation around 0.2 arcsecond. HCsv My own measurements using GSFC SkyView with the DSS via WWW. *Standard deviation around 1-2 arcsecond. HCSb My own measurements on B-band FITS images from the SINGS survey. See Kennicutt et al. PASP XXX, XXX, 2003. *Standard deviation a few tenths of an arcsec; depends on SINGS astrometric calibration. HDW E. Hummel, R.-J. Dettmar, and R. Wielebinski. A&A 166, 97, 1986. NGC 55. Center of maximum HI symmetry coincides with blue-light peak (see G. de Vaucouleurs, ApJ 133, 405, 1961). *Standard deviation 5-10 arcsec at a guess. HH H. Howe, Monthly Notices series from 1898 to 1900. Visual micrometric positions precessed from equinox 1900.0. Standard stars and offsets are not given. *Standard deviations are around 4-8 arcsec at a guess. HHD E. Hummel, J.M. van der Hulst, and J.M. Dickey. A&AS 134, 207, 1984. VLA 2, 6, and 20-cm observations of 16 galaxies. *Standard deviation 0.1 arcsec. HHKK E. Hummel, J.M. van der Hulst, W.C. Keel, and R.C. Kennicutt, Jr. A&AS, 70, 517, 1987. 1.49 GHz VLA observations of 75 galaxies. *Standard deviations are better than one arcsec. HK H. Kobold, Strassburg Annals, 1909. Visual micrometric precessed from equinox 1900, or re-reduced taking proper motion into account if possible. Noted if not re-reduced. *Standard deviation 2-3 arcsec. HKA P. Hickson, E. Kindl, J.R. Auman, Ap.J.Suppl. 70, 687, 1989. Galaxies in compact groups. *Standard deviation 2-3 arcsec. HR W. K. Huchtmeier and O.-G. Richter. A General Catalogue of HI Observations of Galaxies. New York: Springer-Verlag, 1989. Interim source; most positions are not original. *Standard deviation around 10 arcsec. HSA+ C. Hazard, J. Sutton, A.N. Argue, C.M. Kenworthy, L.V. Morrison, and C.A. Murray. Nature (Phys. Sci.) 233, 189, 1971. 3C 273. *Standard deviation 0.2 arcsec. HS1 H. Schultz. Monograph, AN 1541, AN 1555. Micrometric positions, re-reduced with modern positions for the reference stars. All positions here are also in HS2, but the offsets are given here. *Standard deviation 2-3 arcsec. HS2 H. Schultz. MNRAS 35, 135, 1875. Micrometric positions, precessed. *Standard deviation 2-3 arcsec. HWD H.W. Duerbeck, Space Science Reviews 45, 1, 1987. Catalogue of Classical Novae. *Standard deviation unknown, probably depends on original source. Those that I've checked on DSS are within an arcsec. I1 S. Ishikawa, Ann. Tokyo Astron. Obs., 2nd Ser., 21, 437. Virgo Cluster area dwarves. *Standard deviation appears to be about 2 arcsec. IDB R. Garnier, G. Paturel, C. Petit, M.C. Marthinet, and J. Rousseau. "An Image Database." Positions derived from scanned images of POSS1. *Standard deviation appears to be around 5-10 arcsec. Large accidental errors are common, however, and many "galaxies" are actually stars or have stars nearby included in the image. IPds Igor Pesenson. Measurements using IPAC Skyview "pick" command with DSS images clipped from CD-ROM. *Standard deviation 1.2 arcsecond for well-defined images, 2-5 arcsec for larger galaxies. IR Isaac Roberts. IC objects found on his 20-inch reflector plates. *Standard deviation varies depending on size of object. IRAS IRAS Point Source or Small-Scale Structure Catalogues. 1987. I'm replacing these with optical positions. *Standard deviation about 15 arcsec, but varies widely depending on number of scans, position on sky, etc. Inn R.T.A. Innes, from one of the three lists that involve his observations from Cape Town. About a dozen objects; some micrometric measurements, some circle settings. *Standard deviation varies, depending on observing method. J S. Javelle, from IC. Re-reduced using modern positions for comparison stars. *Standard deviation around 4-5 arcsec, but there are occasional blunders in these lists. JA Jason Adamik, private communication via Glen Deen. *Standard deviation 5-6 arcsec at a guess. JB J. G. Bolton, PASP 80, 5, 1968. N = 1 (N1068) *Standard deviation around 0.5 arcsec. JCR,JCO J.J. Condon. ApJ 242, 894, 1980. 6-cm and optical positions for compact radio sources and nuclei of bright spirals. *Standard deviations: 1 arcsec (optical), 0.3 arcsec (radio). JFJS J.F.J. Schmidt, AN 70, 343, 1868; micrometric observations, precessed. *Standard deviation 2-4 arcsec at a guess, but there may be systematic errors, too. JG W. Jaffe and G. Gavazzi, AJ 91, 204, 1986. Coma Supercluster. *Standard deviation around 2 arcsec when position is given to 0.01 seconds and 0.1 arcsec. A few positions are apparently accurate to 0.1 second and 1 arcsec, and 1 second and 0.1 arcmin; these are obviously less accurate. Positions apparently accurate to 0.1 minute and 1 arcmin are from CGCG, and were not entered into the position files. JGr J. Gretchen, priv. comm. via B. A. Skiff. Nuclei of bright galaxies, from multiple short exposure CCD frames with 15-cm reflector (3 arcsec/pixel), reduced wrt GSC 2.2 stars. *Standard deviation 0.2-0.4 arcsec. JGL J. G. Lohse, from NGC. Used only when the object is unrecoverable. *Standard deviation meaningless JGV W. Jaffe, G. Gavazzi, and E. Valentijn, AJ 91, 204, 1986. Groups in the Coma Supercluster. *Standard deviation around 2 arcsec. JH John Herschel's positions, adopted for large diffuse nebulae or open clusters when accurate enough. Also used as nominal positions for objects not found. *Standard deviation 20-30 arcsec. JHS J. H. Safford, from NGC. Used only for NGC 2198: the object is unrecoverable. *Standard deviation meaningless JJ J. E. Jones and B. T. Jones, MNRAS 191, 685, 1980. Fornax Cluster. *Standard deviation around 10 arcsec. JK James Keeler, Lick Obs. Publ. 8, 1908. Measured on Lick Obs. 36-inch reflector plates. *Standard deviation 2-3 arcsec, may have systematic errors depending on the (unspecified) reference star system -- but doesn't look like it. JMcA P.A. Jones and W.B. McAdam. ApJS 80, 137, 1992. Optical positons for southern radio sources. *Standard deviation 0.5 arcsec. JPa J. Palisa, AN 3235 (and others to come as needed). Micrometric discovery observations for nebulae, re-reduced wrt modern positions. *Standard deviation 2-3 arcsec at a guess. JS J.F.J. Schmidt, AN 2097, 1876; Fornax Cluster. *Standard deviation 10 arcsec at a guess, but there are several obvious typos here (corrected when found). JSMo D.L. Jauncey, A. Savage, D.D. Morabito, R.A. Preston, G.D. Nicolson, JSMr and A.K. Tzioumis. AJ 98, 54, 1989. Optical positions for a few radio sources with NGC identifications. *Standard deviation probably around one arcsec for optical positions, and around 0.3 arcsec for radio positions. JT Juan Thome, Cordoba Durchmusterung. Positions for a few IC objects. *Standard deviation 30 arcsec at a guess. Knn n = 1,17. Kiso Ultraviolet Galaxy, list nn. Complete list in B. Takase and N. Miyauchi-Isobe, Publ. Natl. Astron. Obs. Japan, 3, 169, 1993. Positions for pairs not used. Here are the individual references: K01 1984AnTok..192.595T K02 1985AnTok..202.237T K03 1985AnTok..202.335T K04 1986AnTok..212.127T K05 1986AnTok..212.181T K06 1987AnTok..212.251T K07 1987AnTok..212.363T K08 1988AnTok..222..41T K09 1989PNAOJ...1...11T K10 1989PNAOJ...1...97T K11 1990PNAOJ...1..181T K12 1991PNAOJ...2....7T K13 1991PNAOJ...2...37T K14 1991PNAOJ...2..239T K15 1992PNAOJ...2..399T K16 1992PNAOJ...2..573T K17 1993PNAOJ...3...21T K10a 1997PNAOJ...4..153M *Standard deviation claimed to be 0.5 arcsec for stars; it is 1 arcsec for the smaller galaxies, and will be worse for the larger ones, probably on the order of 2 - 3 arcsec. Ka83 J.D. Kaler. ApJ 271, 188, 1983. Positions for planetary nebulae, brought in by B.A. Skiff. *Standard deviation a few arcsec at a guess. Ko+ G. Kojoian and colleagues, VV galaxies, unpublished. *Standard deviation varies from 2 arcsec to more than 20 arcsec depending on size of galaxy. KAR P.C. van der Kruit, R.J. Allen, A.H. Rots. A&A 55, 421, 1977. Optical position for NGC 6946. KCA G. Kojoian, P.A. Chute, C.A. Aumann. AJ 89, 332, 1984. Markarian 1400-1500. *Standard deviation 1-2 arcsec. KD King, I.R. et al. 1993, ApJ, in press (reported in DM, which see). Globulars. *Standard deviation a few arcsec. KEBA G. Kojoian, R. Elliott, M. Bicay, and M. Arakelian, AJ 86, 820, 1981. Arakelian galaxies. N = 203. *Standard deviation "about 1.5 arcsec," but large accidental errors are relatively common (perhaps up to 5% of the list). KEB1 G. Kojoian, R. Elliott, and M.D. Bicay. Astron. J. 86, 816, 1981. Markarian 1096-1302. *Standard deviation 1-2 arcsec. KEB2 G. Kojoian, R. Elliott, and M.D. Bicay. Astron. J. 87, 1364, 1982. Markarian 1303-1399. *Standard deviation about 2 arcsec. KET1 G. Kojoian, R. Elliott, and H.M. Tovmassian. Astron. J. 83, 1545, 1978. Markarian 508-700. *Standard deviation about 5 arcsec. KET2 G. Kojoian, R. Elliott, and H.M. Tovmassian. Astron. J. 86, 811, 1981. Markarian 798-1095. *Standard deviation 1-2 arcsec. KGo P. Kilmartin and A. Gilmore, IAUC 5951, 1994. Offsets (9"w, 7"n; see Treffers etal. IAUC 5946) from SN 1994D in NGC 4526 for nucleus. SN pos is 12 31 29.92 +07 58 36.5 +-0.3 arcsec. *Standard deviation about one arcsec; depends mostly on offset. KHJ Arnold R. Klemola, Robert B. Hanson, and Burton F. Jones. AJ, 94, 501, 1987. Lick Northern Proper Motion Program: NPM1 Reference Galaxies. N = 50,517. Mostly faint (B > 16) galaxies, but many brighter, serving as reference sources for the Lick Proper Motion survey. About 1900 NGC and IC galaxies included. *Standard deviation 0.2 - 0.3 arcsec. KHo,KHr W.C. Keel and E. Hummel. A&A 194, 90, 1988. Optical and 6-cm positions for NGC 2655. *Standard deviation close to 1 arcsec. KK V.E. Karachentseva and I.D. Karachentsev. A&AS 127, 409, 1998. A list of new nearby dwarf galaxy candidates. *Standard deviation around 5-10 arcsec at a guess. KKP I. Karachentsev, V. Karachentseva, S. Parnovsky. Flat Galaxy Catalogue, AN 314, 97, 1993 (revised version with better positions published in 1999; see NED for the full reference). *Standard deviation around 15 arcsec, but frequent larger blunders. KLSn n = 1,i. R. Kirshner, B. Leibundgut, and C. Smith, IAU Circular No. 4900, 4982, 1989-90. Two (so far) galaxies with supernovae. *Standard deviation "better than 2 arcsec." KMH[KA] M. Kontizas, D.H. Morgan, D. Hatzidimitriou, and E. Kontizas. A&AS, 84, 527, 1990. Clusters in LMC. "KMHK" is used for positions from the original paper. "KMHA" is used when brought in from Archinal and Hynes, Star Clusters (AH, which see). *Standard deviation a few arcsec. KOS R. Kirshner, A. Oemler, and P. Schechter. A.J. 83, 1549, 1978. Galaxies in 8 high-latitude fields. *Standard deviation about 6-8 arcseconds at a guess. KP J. Koornneef and S.R. Pottasch. A&A 335 277, 1998. Position for the central star of NGC 650/651. *Standard deviation 0.005 arcsec internal, about 0.2 external. KR K. Reinmuth, reported by B. Skiff for PNe. *Standard deviation around 1 arcsec KRL L. Kohoutek, M.L. Roth-Hoeppner, and S. Laustsen. A&A 162, 232, 1986. Position for the central star of NGC 2818. *Standard deviation 0.2 arcsec internal, 1 arcsec external. KSG R.A. Knop, B.T. Soifer, J.R. Graham, K. Matthews, D.B. Sanders, and N.Z. Scoville. AJ, 107, 920, 1994. VV 114 = IC 1623, 3 components, optical peaks from CCD maps. *Standard deviation around one arcsec. LdR Lord Rosse (prepared for publication by J.L.E. Dreyer). "Observations ...", Sci. Trans. Dublin Roy. Soc., Vol. II, (Ser. II), 1880. *Standard deviation varies from a few arcsec for micrometrically- measured objects to a few arcmin for those roughly estimated on a single night. LdRo Lord Rosse (see above) offset, referred to object as noted. *Standard deviation depends on accuracy of reference object. Lord Rosse's and his assistants' measurements are usually good to 3-4 arcsec, but larger errors occasionally exist. Le[n] F. P. Leavenworth, in AJ 7, 9, 1886 and AJ 7, 57, 1887 Faint nebulae found with the 26-inch refractor at Leander McCormick Observatory. Adopted only when the object cannot be identified. *Standard deviation meaningless. Lo1 W. Lorenz, Strassburg Annals, micrometric observations. *Standard deviation 3-4 arcsec at a guess. Lo2 W. Lorenz, Publ. Astrophys. Obs. Konigstuhl-Heidelberg 6, 19, 1911; photographic astrometry for about 180 bright nebulae. *Standard deviation 1-2 arcsec at a guess. LB R. Love (Nature(PS), 235, 53, 1972) and Bottinelli et al (A&A 12, 264, 1971). N = 1 (Maffei 2). *Standard deviation around 10 arcsec. LBN B. Lynds. ApJ XXX, XXX, 196X. List of bright nebulae found on POSS1. LCRS S. Shectman, et al. ApJ 470, 172, 1996. Las Campanas Redshift Survey. *Standard deviation around 3 arcsec, including systematic errors within individual scans. LEDA Accurate positions for MCG galaxies from the Lyon Extragalactic Database maintained by G. Paturel, C. Petit, and colleagues. Many of these are from other sources quoted here, but many are new measurements on DSS images. Most of the problems with PGC are cleaned up here. *Standard deviation is heterogeneous, but is typically a few arcseconds, exclusive of misidentifications. LGDC J.-F. Le Campion, M. Geffert, M.R. Dulou, and J. Colin. A&AS 95, 233, 1992. Accurate position for NGC 7094, brought in by B.A. Skiff. *Standard deviation about 0.5 arcsec at a guess. LHH P.O. Lindblad, et al. A&AS 120, 403, 1996. NGC 1365. *Standard deviation around 0.5 arcsec. LJG L.J. Greenhill, reported in D.A. Smith and A.S. Wilson. ApJ, 557, 180, 2001. Radio position for the Circinus galaxy. *Standard deviation = 0.1 arcsec. LK L. Kohoutek, positions for planetaries, reported by B.A. Skiff. *Standard deviation around 1 arcsec LMc Micrometric positions from two or more Leander McCormick observers: Ormond Stone, Frank Muller, Frank Leavenworth. Mal M. Malkan, et al. ApJ 237, 432, 1980. UKS 1 (globular). *Standard deviation unknown, probably better than an arcmin. Mar A. Marth. Nebulae found with Laselle's 48-inch reflector at Malta. Positions used only when the nebula is not found by me. *Standard deviation meaningless. Mark E.J. Cooper, "A Catalogue of Stars Near the Ecliptic ...", Vol. 4, p. 183 (quoted by Auwers in his appendix of new nebulae attached to his reduction of WH's catalogue), Dublin, 1856. Nominal position for NGC 7447, which is lost. *Standard deviation meaningless. McB M. L. McCall and R. J. Buta, AJ 109, 2460, 1995. Maffei 1 and two companions. *Standard deviation 0.5 arcsec. McN R. H. McNaught, University of Adelaide, Uppsala Schmidt plates or UK Schmidt plates for SNe parent galaxies. From IAU Circulars Nos. 4726, 5071, 5077, 5132, 5334, 5428. *Standard deviation 0.5 arcsec. Min R. Minkowski, AJ 66, 558, 1961. Positions for 19 galaxies in A2199; offsets from NGC 6166 reduced using GSC position. MCG picked up them all from this paper. *Standard deviation 5 arcsec. Mo C. Monnichmeyer, Publ. Bonn Obs. No. 1, 1895; micrometric observations, re-reduced using modern positions. *Standard deviation about 2 arcsec. Mu[n] Frank Muller, in AJ 7, 9, 1886 and AJ 7, 57, 1887 Faint nebulae found with the 26-inch refractor at Leander McCormick Observatory. Adopted only when the object cannot be identified. *Standard deviation meaningless. MAPS See R.L. Pennington, R.M. Humphreys, S.C. Odewahn, W. Zumach, and P.M. Thurmes, PASP 105, 521, 1993. Minnesota Automated Plate Scanner. *Standard deviation about 0.8 arcsec for small images. MB M.D. Bicay, thesis, 1988. (NED refcode is 1988StanU.T00M....B) *Standard deviation 10 arcsec. MCG Morphological Galaxy Catalogue, B.A. Vorontsov-Velyaminov and colleagues. Used only for missing objects or (primarily) defects on the POSS1 prints. *Standard deviation 2-3 arcmin for defects. MFG G. Marconi, P. Focardi, L. Greggio, Ap. J. 360, L39, 1990. One incorrect measurement for DDO 210, rejected. *Standard deviation meaningless MFSK N. Metcalfe, R. Fong, T. Shanks, and D. Kilkenny. MNRAS 236, 207, 1989. Nine UKST fields to B_J ~16.8. Previously catalogued galaxies included. *Standard deviation about 2 arcsec. MGGP R.P. van der Marel, J. Gerssen, P. Guhathakurta, R.C. Peterson, K. Gebhardt. AJ, Dec 2002. M15. *Standard deviation 0.2-0.3 arcsec. MJC M.J. Cameron. CSUAC No. 219, October 1970. 121 galaxies with Dec < +20 deg and mpg < 12.5. *Standard deviation 10 arcsec. MW Max Wolf. Positions from various AN articles for "nebulae" not found on DSS images or POSS1/SERC prints/films. These objects are probably defects on the early Heidelberg plates. *Standard deviation meaningless. MW08 Max Wolf, AN 4207, 1908. IC 4895 discovery position. *Standard deviation 1 arcmin at a guess. MW1 Max Wolf, Konigstuhl Nebulae, List 1, Publ. Astrophys. Obs. Heidelberg-Konigstuhl, 1, 11, 1902. Precessed from 1875. (N.B. for List 2, see Schwassmann, source Sn.) The positions from this series were keyed by Evelyn Deen, and proofread by Glen and Evelyn Deen. When an object from this series has been verified on a print of the original plate, the comments column has the type from the POSS1 followed by the comment "(verified)". *Standard deviation 3-5 arcsec. MW3 Max Wolf, Konigstuhl Nebulae, List 3, Publ. Astrophys. Obs. Heidelberg-Konigstuhl, 1, 125, 1902. Measured on 16" Bruce refractor plates. Precessed from 1875. Coma Cluster. *Standard deviation 3-5 arcsec. MW4 Max Wolf, Konigstuhl Nebulae, List 4, Publ. Astrophys. Inst. Konigstuhl-Heidelberg, 2, 57, 1906. Precessed from 1875. *Standard deviation 3-5 arcsec. MW5 Max Wolf, Konigstuhl Nebulae, List 5. Publ. Astrophys. Inst. Konigstuhl-Heidelberg, 2, 77, 1906. Precessed from 1875. Most are in IC2. There are many plate defects and faint stars, double stars, etc in these lists, but the true nebulae have good positions. *Standard deviation 3-5 arcsec. MW6 Max Wolf, Konigstuhl Nebulae, List 6. Publ. Astrophys. Inst. Konigstuhl-Heidelberg, 2, 89, 1906. Precessed from 1875. *Standard deviation 3-5 arcsec. MW7 Max Wolf, Konigstuhl Nebulae, List 7. Publ. Astrophys. Inst. Konigstuhl-Heidelberg, 3, 77, 1909. Precessed from 1875. *Standard deviation 3-5 arcsec. MW8 Max Wolf, Konigstuhl Nebulae, List 8. Publ. Astrophys. Inst. Konigstuhl-Heidelberg, 3, 87, 1909. Precessed from 1875. *Standard deviation 3-5 arcsec. MW16 Max Wolf, Konigstuhl Nebulae, List 16. Veroff. ... Heidelberg, 8, No. 11, p. 18, 1928. Precessed from 1900. *Standard deviation 1-2 arcsec. MW17 Max Wolf, AN 205, 79, 1917. Photographic position for NGC 6946, precessed from equinox 1917.0. *Standard deviation probably around 1 arcsec. NH S.G. Neff and J.B. Hutchings. AJ 103, 1746, 1992. 6- and 20-cm positions for IRAS galaxies. *Standard deviation 0.5 arcsec. NGC J.L.E. Dreyer. NGC. MemRAS 49, 1, 1888. NMP N.M. Parrish. Observations of nebulae, re-reduced wrt modern star positions, quoted in Ormond Stone, "Southern Nebulae", Publ. Leander McCormick Obs, Vol. 1, p. 173, 1893. RA's determined by clock, Dec's by micrometer. *Standard deviation, a few arcsec. OSt[n] Ormond Stone, in AJ 7, 9, 1886 and AJ 7, 57, 1887. Faint nebulae found with the 26-inch refractor at Leander McCormick Observatory. Adopted only when the object cannot be identified. *Standard deviation meaningless. OCW O. C. Wendell, Harvard Circular 42, 1899. Micrometric position for IC 4816 = Nova Sgr 1898. This is the discovery position. *Standard deviation probably a few arcsec. OGLE G. Pietrzynski, M. Udalski, M. Kubiak, M. Szymanski, P. Wozniak, and K. Zebrun. Acta Astronomica 48, 175, 1998. SMC clusters from OGLE. *Standard deviation probably a few arcsec. Pds G. Paturel, C. Petit, Ph. Prugniel, and R. Garnier. A&AS 140, 89, 1999. DSS positions for miscellaneous galaxies. n = 17335. Identifications for many galaxies -- especially the zwicky compacts -- are suspect and need to be checked. *Standard deviation 1-2 arcsecond for well-defined images, 2-5 arcsec for larger galaxies. Pds2 G. Paturel, et al. A&AS 144, 475, 2000. See Pds above. *Standard deviation 1-2 arcsecond for well-defined images, 2-5 arcsec for larger galaxies. Pe Peters, Copernicus, micrometric observations. Precessed. *Standard deviation probably around 3-5 arcsec at a guess. Pec Pechule, various articles, primarily in AN. See IC1/2 for a list. *Standard deviation 2 arcsec at a guess. Pick E.J. Pickering, AN 105, 335, 1883. Nominal position for NGC 6766; claimed to be an emission-line nebula, but no planetaries nearby. *Standard deviation meaningless. Pls J. Palisa, AN 116, 337, 1887. Micrometric positions for a few NGC/IC objects, precessed. *Standard deviation 2-3 arcsec at a guess. Po Porter, Cinncinati Obs., micrometric observations re-reduced. *Standard deviation around 1-2 arcsec. Pr D. Proust, Meudon Observatory, IAU Circular No. 5134. *Standard deviation probably 1-2 arcsec. PA C. Pollas and D. Albanese, IAU Circular No. 5040. NGC 5917. *Standard deviation probably 1-2 arcsec. PC L. Padrielli and R.G. Conway. A&AS 27, 171, 1977. 4C sources identified with galaxies. *Standard deviation 0.8 arcsec. PCR P. Parma, R.A. Cameron, and H.R. de Ruiter. AJ 102, 1960, 1991. Optical positions for "dumbbell" galaxies which are radio sources. *Standard deviation 2-3 arcsec. PEES B.A. Peterson et al. MNRAS 221, 233, 1986. Optical positions from Southern Sky Survey IIIa-J plates. *Standard deviation "better than 1 arcsec." PKe P. Kempf. (Publ. Astrophys. Obs. Potsdam, No. 29, 1892). Micrometric measures, precessed, not re-reduced unless noted. *Standard deviation 2-3 arcsec at a guess. PK67 L. Perek and L. Kohoutek. Catalogue of Galactic Planetary Nebulae, 1967. Positions brought in by B.A. Skiff. *Standard deviation a few arcsec at a guess. PL M. Postman and T. Lauer. ApJ 440, 28, 1995. Positions from DSS for brightest galaxies in Abell clusters. Precessed from J2000.0. *Standard deviation 1.0 arcsec. PPAO S. Piatek, C. Pryor, T.E. Armandroff, and E.W. Olszewski. AJ 123, 2511, 2002. Draco Dwarf. Center of isopleths from star counts. *Standard deviation "about 0.1 arcminutes". PPM Positions and Proper Motions (S. Roeser and U. Bastian, Heidelberg, 1991). M31, M32, M92, N2261, N6543. And a few others. *Standard deviation about 0.2 arcsec. QFW H. Quintana, P. Fouque, and M.J. Way. A&A 283, 722, 1994. Optical positions for the NGC 1400/1407 Group, measured on ESO Quick B survey copy plate. *Standard deviation 1.5 arcsec. R Rumker, AN 63, 305, 1864, etc. Micrometric observations, re-reduced with modern positions for the reference stars. *Standard deviation probably 2-3 arcsec. Rup M.P. Rupen, AJ 102, 48, 1991. Neutral hydrogen mapping of NGC 891 and NGC 4565. *Standard deviation around 1-2 arcsec. R16 Karl Reinmuth, Konigstuhl plates, 1916. Precessed from equinox 1900. *Standard deviation probably 2-3 arcsec. R20 Karl Reinmuth, Konigstuhl plates, 1920. Precessed from equinox 1900. *Standard deviation probably 2-3 arcsec. R27 Karl Reinmuth 1927 list of Virgo Cluster galaxies. *Standard deviation about 1 arcsec, but there may be systematic errors depending on reference star system. R28 Karl Reinmuth, Veroff. ... Heidelberg 8, 133, 1928. Precessed from equinox 1900.0. *Standard deviation around 1 arcsec at a guess. See previous. R29 Karl Reinmuth, Veroff. ... Heidelberg 8, 167, 1929. Precessed from equinox 1900.0. *Standard deviation around 1 arcsec at a guess. See previous. R32 Karl Reinmuth, Veroff. ... Heidelberg 8, 192, 1932. Precessed from equinox 1900.0. *Standard deviation around 1 arcsec at a guess. See previous. RB R. J. Buta, ApJS XX, XXX, 1987. Position for lsb galaxy "160 arcsec west, 34 arcsec south of NGC 7531." RC Ralph Copeland, quoted in NGC for NGC 295, not found. *Standard deviation meaningless. RC2 Second Reference Catalogue of Bright Galaxies (de Vaucouleurs et al. 1976), primarily from GH, GHD1,2 (see above), Cameron, Glanfield and Cameron (bright southern galaxies, all replaced by ESO), Sandage's southern lists, and my own measurements (source HC, above). These are being replaced as I identify the original sources. *Standard deviation runs from 5 arcsec to 20 arcsec. RC3 Third Reference Catalogue of Bright Galaxies (de Vaucouleurs et al. 1991). Not used as a source of positions. *Standard deviation varies between 1 arcsec and 20 arcsec. RD D. Reynaud and D. Downes, A&A 319, 737, 1997. Dynamical center of NGC 1530 from high-resolution CO(1-0) observations. *Standard deviation on the order of 1 arcsec. REds R. Erdmann, DSS for NGC/IC objects. Precessed from J2000.0. *Standard deviation on the order of 1 arcsec. RG R.F. Griffin, AJ 68, 421, 1963. Galaxies in the fields of 3C sources. *Standard deviation 0.3 arcsec. RGMH R. Giovanelli, M. Haynes, and colleagues; various papers. *Standard deviation about 6 arcsec. RGO Royal Greenwich Observatory, (Dreyer?), MNRAS 71, 509, 1911. Photographic positions for far northern galaxies poorly observed by the Herschels, precessed from equinox 1900.0. *Standard deviation about 1 arcsec at a guess, though there could be systematic offsets depending on reference system. RH O.-G. Richter, W.K. Huchtmeier, and colleagues. Optical positions for galaxies in their HI Catalogue and/or various papers. *Standard deviation 8-10 arcsec. RL G.H. Rieke and F.J. Low. ApJ 176, L95, 1972. 10-um position for nucleus of NGC 253. *Standard deviation around 1 arcsec. RLT G.H. Rieke, M.J. Lebofksy, R.I. Thompson, F.J. Low, and A.T. Tokunaga. ApJ 238, 24, 1980. 2.2-um position for M82, "about 3 arcsec off the visual peak." *Standard deviation 1.5 arcsec. RSA Allan Sandage and Gustav A. Tammann. The Revised Shapley-Ames Catalogue ..., Carnegie Publication #635, second edition, 1987. *Standard deviation around 10 arcsec. RWH R.W. Hunstead. MNRAS 152, 277, 1971. Optical positions for radio point sources. Four bright galaxies (plus fainter not entered). *Standard deviation 0.4 arcsec. RTBB H.J.A. Rottgering, Y. Tang, M.A.R. Bremer, A.G. de Bruyn, G.K. Miley, R.B. Rengelink, M.N. Bremer. MNRAS 282, 1033, 1996. 325 MHz position for Markarian 1498 = WN 1626+5153. *Standard deviation 4 arcsec. Sf Schoenfeld, micrometric observations, inferred from other lists until I can find a copy of his papers. *Standard deviation looks to be around 3 arcsec. Sn Schwassmann, A. Publ. Astrophys. Obs. Konigstuhl-Heidelberg 1, 17, 1902. Precessed from equinox 1900.0. Virgo Cluster area. *Standard deviation about 3-5 arcsec. Spt R. Spitaler, various publications referenced in NGC and IC. Micrometric positions re-reduced wrt GSC/SAO/PPM/Tycho-2 etc. *Standard deviation a few arcsec. Stn E. Stephan's original lists, n = 1 - 13. Micrometric positions, re-reduced wrt GSC/SAO/PPM/Tycho-2 etc, or precessed. St1 = AN 76, 159, 1870 = AN 1810; and MNRAS 32, 23, 1871 St2 = AN 78, 295, 1872 = AN 1867; and MNRAS 32, 23, 1871 St3 = AN 79, 61, 1872 = AN 1876; and MNRAS 32, 231, 1872 St4 = AN 81, 303, 1873 = AN 1939; and MNRAS 33, 433, 1873 St5 = AN 83, 51, 1874 = AN 1972; and MNRAS 34, 75, 1873 St6 = AN 83, 137, 1874 = AN 1977 St7 = CR 83, 328, 18xx St8 = MNRAS 37, 334, 1877; and AN 89, 213 and 263, 1877 = AN 2126 and AN 2129 St9 = CR 87, 869, 18xx St10 = CR 90, 837, 18xx St11 = CR 92, 1128, 18xx; ibid p. 1183; ibid p. 1260; and AN 100, 209, 1881 = AN 2390. St12 = CR 94, 546; 18xx; ibid p. 609; and AN 105, 81, 1883 = AN 2502. St13 = CR 100, 1043, 18xx; ibid p. 1107; and AN 111, 321, 1885 = AN 2661. *Standard deviation about 2-3 arcsec. Sxy Carl Seyfert's dx, dy measurements refered to mean position of NGC 6027 for other members in the group (PASP 63, 72, 1951). N = 5 *Standard deviation a few arcsec. Swn Lewis Swift's original lists, n = 1 - 12. Adopted only when the object in question is not found by me. Nominal positions only. *Standard deviation meaningless. SAO SAO position adopted. Used for a few non-stellar objects, primarily planetaries or stars in clusters or in the center of diffuse nebulae. Also used for a few stars thought by the original observer to be nebulous -- nebulae may or may not be present on modern photographs. *Standard deviation 0.3 to 1.0 arcsec. SBC J.L. Sersic, E. Bajaja, and R. Colomb. A&A 59, 19, 1977. N2915. *Standard deviation a few arcsec (N.B. Sec of RA is wrong in SBC's Table 2.) SBG1 N. Santagata, L. Basso, M. Gottardi, G. Palumbo, and G. Vettolani. A&AS 70, 189, 1987. CGCG galaxies, Paper 2 (see VPS). From machine readable files sent by G. Palumbo. *Standard deviation depends on size of galaxy, varies from 1 arcsec to 5 arcsec. SBG2 N. Santagata, L. Basso, M. Gottardi, G. Palumbo, G. Vettolani, and M. Vigotti. A&AS 70, 191, 1987. CGCG galaxies, Paper 3 (see VPS). From machine readable files sent by G. Palumbo. *Standard deviation depends on size of galaxy, varies from 1 arcsec to 5 arcsec. SBIB D. Sprayberry, G.M. Bernstein, C.D. Impey, G.D. Bothun. ApJ, 438, 72, 1995. Low surface brightness galaxies. *Standard deviation 2-3 arcsec. SC Sidney Coolidge. AN 1453. Positions for ``nebulae'', apparently micrometrically measured; or for nebulae not found by me. *Standard deviation looks to be around 5 arcsec (or meaningless if not found). SCO S.C. Odewahn, PhD thesis, Univ of Texas, 1989. Position for NGC 2366 from isophotes. *Standard deviation a few arcsec at a guess. SCOS N.C. Hambly, A.C. Davenhall, M.J. Irwin, H.T. MacGillivray. MNRAS 326, 1315, 2001 and references therein. Positions from SuperCOSMOS scans of sky survey plates. Tycho-2 provided reference stars. *Standard deviation 0.2 arcsec for B_J brighter than 19, 0.3 arcsec for B_J brighter than 22 -- for stellar images, of course. SDP S.D. Peterson. Astron. J. 78, 811, 1973. Markarian 1 - 507. *Standard deviation 6-8 arcsec. SDSS Sloan Digital Sky Survey, 2001-2006+-, usually via NED. Tied to Tycho-2 reference stars unless UCAC is available. *Standard deviation 0.2 arcsec. SESO A. Acker, F. Ochsenbein, B. Stenholm, R. Tylenda, J. Marcout, and C. Schohn. The Strasbourg-ESO Catalogue of Galactic Planetary Nebulae (Garching: ESO), 1992. A few positions quoted by Condon and Kaplan, ApJS 117, 361, 1998 (source CK, which see), and by Brian Skiff. *Standard deviation unknown, but probably a few arcsec. SGC Southern Galaxy Catalogue (Corwin et al. 1985), not from ESOB: visual micrometric measurements (primarily Porter 1911), or my own measurements on PSS or SSS plates/prints/films. *Standard deviation 5-6 arcsec or better. SGsv Steve Gottlieb, private communication. Positions for a few IC objects estimated from SkyView images. *Standard deviation 3-4 arcsec at a guess. SHM Kathleen Spellman, George Helou, and Barry Madore (PASP 101, 360, 1989). SGC galaxies without ESO positions. N = 372 *Standard deviation 6-8 arcsec. SIB Solon I. Bailey, HA 60, 1908. List of the 263 largest, brightest nebulae and clusters. Several IC objects here. Positions given to 1 arcmin only; sufficient for identification. *Standard deviation 1-2 arcmin. SIMA SIMBAD's adopted position for star clusters in the LMC, quoted by B.A. Archinal in Star Clusters (see source AH). *Standard deviation 10 arcsec at a guess. SIMB SIMBAD's adopted position for planetary nebulae (Acker et al, 1996 version of the Strasbourg Catalogue, CDS catalogue number V/100), quoted by B.A. Skiff. *Standard deviation around one arcsec. SJL A. Sandqvist, S. Jorsater, and P. Lindblad. A&A 110, 336, 1982. Position for NGC 1365 quoted in S. Jorsater and G.A. van Moorsel, AJ 110, 2037. *Standard deviation quoted as 4 arcsec. SK E.P. Smith and N.E. Kassim. AJ 105, 46, 1993. A few optical positions for 20-cm radio sources. *Standard deviation probably around 1-2 arcsec. SL Brian A. Skiff, measured on plates taken by Lampland at Lowell Obs. PPM stars used for astrometric net. *Standard deviation around 0.2-0.3 arcsec. SMB E. Slezak, G. Mars, A. Bijaoui, C. Balkowski, P. Fontanelli. A&AS 74, 83, 1988. Galaxies in the "Coma Supercluster", a Palomar Schmidt field north-following A1656, but not including it. Precessed from equinox 2000.0. *Standard deviation around 8-10 arcsec. Large accidental errors have been seen. SNp To be recovered. Probably a supernova parent galaxy. NGC 673 is one. SP E.P. Smith et al. ApJS 104, 287, 1996. UV positions from UIT on Astro-1 Space Shuttle mission. *Standard deviation 2 arcsec. SPC Brian A. Skiff, Lowell Observatory PDS scans of 13" Pluto Camera (astrograph) plates, 1988 - 89. ESGC galaxies. Also miscellaneous positions measured on the same series of plates. *Standard deviation 2-3 arcsec. SPF Ditto, but on 18-inch Palomar Schmidt films taken by Gene and Caroline Shoemaker for their asteroid search. *Standard deviation is about 1 arcsec. SPL S.P. Langley in Harvard Annals 8, Part 1, p. 62, 1882. Nominal position for NGC 3355; nothing is there. *Standard deviation meaningless. SPP Ditto, but on PSS prints or plates. *Standard deviation is around 1 arcsec. STMW S.E. Schneider, T.X. Thuan, C. Magri, and J.E. Wadiak. Ap. J. Suppl. 72, 245, 1990. UGC lsb galaxies. *Standard deviation about 10 arcsec. STMM S.E. Schneider, T.X. Thuan, C. Magri, and J. Miller. Ap. J. Suppl. 81, 5, 1992. UGC lsb galaxies. Many positions were apparently taken from DC, FT, RGMH, and STMW without acknowledgment; I've removed these. *Standard deviation about 10 arcsec. SW Stephen Shawl and Raymond White, A.J. 91, 312, 1986. Positions of 109 galactic globular clusters. *Standard deviation about 1 arcsec. SWX D.A. Smith and A.S. Wilson. ApJ, 557, 180, 2001. X-ray position for the Circinus galaxy from a Chandra ACIS map. *Standard deviation = 0.1 arcsec. SVD Schuyler Van Dyk, private communication. NGC 150. *Standard deviation about 1 arcsec. T[n] W. Tempel. n = list number. Micrometric positions precessed from Tempel's equinox, typically around 1880. *Standard deviation probably a few arcsec. TDM Tom DeMary, open cluster positions from USNO A2.0 displayed with HyperSky, eyeball centers, precessed from J2000.0. *Standard deviations between about 10 arcsec to 1-2 arcmin, depending on cluster size. TE Thomas Espin, MNRAS 54, 327, 1894; and AN No. 3633, 1900. Fifteen "nebulae" or clusters in MN, seven nebulae in AN. Positions estimated from BD charts, used only for objects not found. *Standard deviations meaningless. TH Turner, J.L. and Ho, P.T.P. ApJ, 421, 122, 1994. 2- and 6-cm nuclear continuum sources in 8 spiral galaxies. *Standard deviation 0.5 arcsec, except for NGC 5194 where it is 0.1 arcsec. TH1 Turner, J.L. and Ho, P.T.P. ApJ, 268, L79, 1983. 2- and 6-cm nuclear sources in 3 spiral galaxies. *Standard deviation about an arcsec. THB Turner, J.L, Ho, P.T.P., and Beck, S.C. AJ 116, 1212, 1998. 2- and 6-cm continuum observations of NGC 5253. *Standard deviation a few tenths of an arcsec. THS T. H. Safford, from IC. Used only when the object is unrecoverable. *Standard deviation meaningless TML J.H. Taylor, R.N. Manchester, A.G. Lyme. ApJS 88, 529, 1993. Pulsar catalogue. J2000.0 positions precessed to B1950.0 for a few pulsars associated with SNRs (e.g. Crab pulsar = NGC 1952). *Standard deviation 0.5 arcsec or better. TVP Tully, R.B., Verheijen, M.A.W., Pierce, M.J., Huang, J.-S., and Wainscoat, R.J. Ursa Major Cloud members, from GSC stars on CCD images. *Standard deviation about 1 arcsec. Ty2 E. Hog et al. A&A 355, 27L, 2000. Tycho-2 positions, primarily for individual stars, but some planetaries (courtesy of Brian Skiff), too. *Standard deviation 0.007 arcsec for stars brighter than V = 9, 0.06 for fainter stars. UA10 USNO-A1.0. From scans of original sky survey plates by USNO team headed by D. Monet. *Standard deviation about 0.3 arcsec for stars, 1-2 arcsec for extended objects (e.g. galaxies) larger than about an arcmin. UA20 USNO-A2.0. From scans of original sky survey plates by USNO team headed by D. Monet; reprocessing of A1.0 to put it on ICRS. *Standard deviation about 0.2 arcsec for stars, 1-2 arcsec for extended objects (e.g. galaxies) larger than about an arcmin, probably around 0.4 - 0.5 arcsec for smaller galaxies. UB10 USNO-B1.0. From scans of original sky survey plates by USNO team headed by D. Monet. Pretty much like USNO-A1.0, but includes proper motions and star/non-star classifications. *Standard deviation about 0.2 arcsec for stars, 1-2 arcsec for extended objects (e.g. galaxies) larger than about an arcmin, probably around 0.4 - 0.5 arcsec for smaller galaxies. UCA1 USNO CCD Astrograph Catalog (preliminary edition) "UCAC1". N. Zacharias, et al, CD-ROM (Washington: USNO), March 2000. A few bright galaxies are included. This extends from the south equatorial pole to about -20 deg, and has now been completely replaced by UCAC2, which see. *Standard deviation "20 mas for stars in the magnitude range R = 9-14.5 and about 70 mas at the limiting magnitude of 16." UCA2 USNO CCD Astrograph Catalog (second edition) "UCAC2". N. Zacharias, S.E. Urban, M.I. Zacharias, G.L. Wycoff, D.M. Hall, M.E. Germain, E.R. Holdenreid, and L. Winter. AJ 127, 3043, 2004. This completely replaces UCAC1 and extends it north to at least +40 deg, and up to +50 deg at some RAs. *Standard deviation "20 mas for stars in the magnitude range R = 9-14.5 and about 70 mas at the limiting magnitude of 16." UJ10 Sampler of USNO-A1.0, which see. *Standard deviation 0.3 arcsec for stars, 1-2 arcsec for galaxies. UGCo UGC Notes offset (from UGC galaxies with a precise positions) in arcmin and position angle converted to delta RA and delta Dec. *Standard deviation about 6-8 arcsec (also depends on accuracy of position used as reference). UJ10 UJ 1.0. From scans of short-exposure IIIa-J POSS-2 plates by USNO, courtesy of D. Monet. *Standard deviation about 0.3 arcsec for stars, 1-2 arcsec for extended objects (galaxies). USNO See K.J. Johnston, et al, AJ 110, 880, 1995 for background. The positions actually used come from USNO's 1996-11 solution, downloaded in January 1997 from their public ftp partition. VLBI radio reference sources. These define the FK5 radio reference frame. Precessed from J2000.0 to B1950.0 using J. Bennett's IPAC precession/conversion routines. *Standard deviation better than 3 milliarcseconds in all cases, and better than 1 milliarcsec in most cases. Accuracy on this level is destroyed by the precession program. Can ANY precession routine do justice to these positions? UW J.S. Ulvestad and A.S. Wilson. ApJ 343, 659, 1989. 2, 6, and 20 cm VLA observations of Seyfert nuclei. n = 27. *Standard deviation around 0.2 arcsec. UWS J.S. Ulvestad, A.S. Wilson, and R.A. Sramek. AJ 247, 419, 1981. 1.465 GHz and/or 4.885 GHz VLA observations of Seyfert nuclei. n = 16. *Standard deviation 0.1-0.3 arcsec. UZC The Updated Zwicky Catalogue. E. Falco, et al. PASP, 111, 438, 1999. GSC or DSS positions for about 19,000 CGCG galaxies with m_p <= 15.5, plus a few hundred other galaxies. The original list had many misidentifications and stars included. These have been mostly removed in the published version. *Standard deviation around 1-1.5 arcsec. vdH+ J.M. van der Hulst, P.C. Crane, and W.C. Keel. AJ 86, 1175, 1981. 6 cm VLA observations of spiral galaxy nuclei. *Standard deviation 0.3 or 0.8 arcsec. vdK1 P.C. van der Kruit. A&A 15, 110, 1971. 21.2-cm positions for 13 galaxies. *Standard deviation about 2 arcsec. vdK2,3 P.C. van der Kruit. A&A 29, 231 and 249, 1973. 21.2-cm positions for bright galaxies. N3556 position interpolated from contours in Fig. 6 of vdK3 by me. *Standard deviation less than 1 arcsec (except for N3556; that is probably 3-4 arcsec). Vig Vigotti, M., Grueff, G., Perley, R., Clark, B.G., Bridle, A.H. AJ 98, 419, 1989. Radio sources measured on POSS prints w.r.t. AGK3 stars. *Standard deviations about 0.7 arcsec for stellar images, probably several arcsec for things like M51. V Veron, P. ApJ 144, 861, 1966. Radio sources. *Standard deviation about 1 arcsec. VC de Vaucouleurs and Corwin, ApJ 295, 287, 1985. M31 from several astrometric sources. *Standard deviation about 0.2 arcsec. VCC B. Bingelli, A. Sandage, and G. A. Tammann. A.J. 90, 1681, 1985. Virgo Cluster Catalog. *Standard deviation about 10 arcsec. VHSW S.D. Van Dyk, S.D. Hyman, R.A. Sramek, and K.W. Weiler. IAU Circular 6045. VLA 6- and 20-cm position for NGC 6946. *Standard deviation probably 0.2-0.3 arcsec. VL G. de Vaucouleurs and R. Leach. PASP 93, 190, 1981. M31 and M33. *Standard deviation about 0.2 arcsec. VPC C.K. Young and M.J. Currie. A&AS 127, 367, 1998. The Virgo Photometry Catalogue. Positions taken from RC3 removed. *Standard deviation 3-4 arcsec. VPD M.B. Vila, A. Pedlar, R.D. Davies, E. Hummel, and D.J. Axon. MNRAS 242, 379, 1990. 20- and 6-cm positions for bright Sbc galaxies. *Standard deviation 0.3 arcsec when given to 0.1 arcsec, 2-3 arcsec when given to 1 arcsec. VPS G. Vettolani, G. Palumbo, and N. Santagata. A&AS 64, 247, 1986. CGCG galaxies, Paper 1. From machine readable files sent by G. Palumbo. *Standard deviation depends on size of galaxy, varies from 1 arcsec to 5 arcsec. VPS1 Ditto, for CGCG fields 502-5. Typed by me. *Standard deviation depends on size of galaxy, varies from 1 arcsec to 5 arcsec. VV1,2 Veron, M.P. and Veron, P. A&A 42, 1, 1975 and A&AS 29, 149, 1977. Radio sources. *Standard deviation about 0.5 arcsec. VVAG Veron, M.P., Veron, P., Adgie, R.L., and Gent, H. A&A 59, L19, 1976. Radio sources. *Standard deviation about 0.5 arcsec. Win A. Winnecke, Strassburg Annals, Vol. 3, 1909. Micrometric measurements of several hundred NGC objects, re-reduced using modern positions for the reference stars. *Standard deviation 1-2 arcsec at a guess. Wolf Max Wolf, AN 4082 = AN 171, 27, 1906. Nominal position for IC 1831, currently a lost object. *Standard deviation meaningless. WDP W.D. Pence, thesis (1981). NGC 253. *Standard deviation a few arcsec. WF Wilhelmina P. Fleming, Harvard Annals 60 and references therein. "Stars" with emission lines; most are PNe or -- in the LMC -- HII regions. Positions used only when the object cannot be positively identified (e.g. IC 1292). Original positions were given to 0.1 minute and 1 arcmin. (Also see source WPF.) *Standard deviation meaningless, but the identified nebulae have positions typically good to 1-2 arcmin. WGT W.G. Tifft, Probably Coma Cluster or double galaxies (I've lost the reference; check AJ's or ApJ's). *Standard deviation a few arcsec at a guess. WH W. Herschel, Collected Papers (ed. Dreyer, 1912). Offsets reduced w.r.t. modern positions for reference stars. Used only for objects not recovered on the sky surveys (e.g. NGC 421, NGC 4317, etc). *Standard deviation is meaningless. WK W. Keel, reported in CCR (which see). NGC 992. *Standard deviation better than 1 arcsec. WKF P.A. Woudt, R.C. Kraan-Korteweg, A.P. Fairall, H. Bohringer, V. Cayatte, and I.S. Glass. A&A, in press, 1998. *Standard deviation unknown, probably a few arcsec. WM A. S. Wilson and E. J. A. Meurs (A&ASuppl. 33, 407, 1978) Seyferts. N = 7. *Standard deviation around 0.2 arcsec. WMe Wilson and Meurs, as above, but image noted as "large or asymmetric, so the errors are typically a few arcsec." *Standard deviation around 3 arcsec at a guess. WPF Wilhelmina P. Fleming, Harvard Circulars No. 32 and 60. Various NGC and IC objects found on Harvard plates. *Standard deviation 10-15 arcsec. WR W. Romanishin. AJ, Aug 1990. LSB galaxies. *Standard deviation around 3 arcsec. WS Wolfgang Steinicke. Positions for NGC/IC objects from RealSky. Identifications corrected when known wrong, flagged with a question mark when WS position is different from another position and an investigation is not yet done. Declinations are systematically south by 2 arcsec. *Standard deviation 3 arcsec or better. WU1 A.S. Wilson and J.S. Ulvestad, ApJ 260, 56, 1982. 6 and 20 cm position for NGC 5548. *Standard deviation 0.2 arcsec. WU2 A.S. Wilson and J.S. Ulvestad, ApJ 275, 8, 1983. 6 and 20 cm position for NGC 1068. *Standard deviation 0.2 arcsec. WW A.S. Wilson and A.G. Willis, ApJ 240, 429, 1980. 6-cm positions for Seyfert nuclei. *Standard deviation 0.4 arcsec. WWB Wynn-Williams and E. Becklin. ApJ 290, 108, 1985. Optical (Johnson V) position for NGC 2903 quoted in VPD. *Standard deviation better than 1 arcsec. WWD D. & B. Wills and J. Douglas. AJ 78, 521, 1973. Optical positions for radio sources. *Standard deviation about 0.5 arcsec. WYC A.S. Wilson, Y. Yang, and G. Cecil. ApJ 560, 689, 2001. 20-cm nuclear source in NGC 4258. *Standard deviation 0.1 arcsec. YOF N. Yasuda, S. Okamura, and M. Fukugita. ApJS 96, 359, 1995. Optical positions for spirals in Virgo. *Standard deviation 0.9 arcsec. YZYH Q.R. Yuan, Z.H. Zhu, Z.L. Yang, and X.T. He, A&AS, 115, 267, 1996. APM positions for IRAS galaxies in Virgo. *Standard deviation around 1-2 arcsec. ZGT F. Zwicky, H. Gates, and D. Taylor, unpublished ONR Report, 1955. *Standard deviation around 5-7 arcsec at a guess. ZH F. Zwicky and E. Herzog (CGCG II, p. 319). Special Coma Cluster map and table. *Standard deviation around 10 arcsec. Others as noted in comments, though I was able to clean up almost all of these thanks to a list of missing sources supplied by Francois Ochsenbein in July of 2004 as he was preparing the positions and notes files for entry into CDS's catalogue database.