VI/19ivo://CDS.VizieR/VI/19CDSLandolt A.U.2013-02-26T12:13:01Z1997-12-09T22:24:49ZCDS support team

CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France

cds-question@unistra.frvisible-astronomyWide-band photometryphotometrymorgan-keenan-classificationThe UBV system was originally defined by ten bright standard stars, primarily in the northern sky. These stars are too bright to be used with large telescopes and cannot be reached from southern observatories. This catalog is a careful compilation of data on fainter stars in the equatorial Selected Areas. They are intended as a new set of standards which can be used to define the UBV system at fainter magnitudes in both hemispheres. The stars range in V between 6.0 and 14.9 with most between 9.0 and 13.0. Introduction: A discussion of modern broad-band photometric systems has been given by Johnson and Morgan (1953). The stars upon which this system is based are tabulated in Johnson and Morgan (1953), Johnson and Harris (1954) and Johnson (1955,1963). The stars which define the system are nearly all bright stars. The recent large body of southern hemisphere standards (Moreno, Moreno, Stock, Torres and Wroblewski 1966) also consists of bright stars. The stars now recommended for use as UBV standard stars were redefined at the XIVth General Assembly of the IAU to be those objects brighter than V = 5.0 mag between DE = +- 10 deg; however, most of them are still brighter than desirable for the observing techniques and photometers used by most astronomers. There exist, scattered around the sky, photoelectric sequences of fainter stars which are tied into the UBV system. Such sequences, more often than not, are located in galactic or globular star clusters. However, they really are not all on the same precise photometric system, as an intercomparison of two or more observers' data on a given cluster many times shows (see, for example, Landolt 1964); slight zero-point differences and color equation problems occur. Many times, sequences are defined only by one, two or three observations per star. Hence, one ought not use these sequences for extension to fainter objets in extended programs around the sky. There has been much discussion, both privately and in the literature (Blaauw 1955; Walker 1959; Stoy 1958, 1961; Greaves 1955), of the desirability of a faint sequence of standard stars distributed over the sky. Although a variety of useful photometric systems has been established in recent years, the broad-band UBV system still has an important future role in astronomical research. Particularly is this true for the fainter objects to be observed with the big reflectors, where a well defined, widely adopted standard photometric system can be used to great advantage in the initial reconnaissance of faint celestial objects. An attempt is made in this paper to provide a homogeneous set of UBV standard stars in the celestial equatorial Selected Areas. By doing so, astronomers in both hemispheres will have access to faint standard stars readily accessible to the largest telescopes. It is not claimed that this system is a priori better than other fine photoelectric sequences scattered in various regions about the celestial sphere. However, the stars observed herein were thoroughly tied together completely around the sky during many observing sessions from the same site, and using the same type of equipment throughout the duration of the observing program. Therefore, the system should be internally quite accurate and consistent. Many, but not all, of the stars in this catalog are included in later catalogs: 2118 and 2183.1973AJ.....78..959Lhttps://cdsarc.cds.unistra.fr/viz-bin/cat/VI/19CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toII/118 : UBVRI standards around Celestial Equator (Landolt 1983)II/183 : UBVRI standards in the magnitude range 11.5<V<16.0 (Landolt 1992)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=VI/19https://vizier.iucaa.in/viz-bin/VizieR-2?-source=VI/19http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=VI/19https://vizier.cds.unistra.fr/viz-bin/votable?-source=VI/19https://vizier.iucaa.in/viz-bin/votable?-source=VI/19http://vizieridia.saao.ac.za/viz-bin/votable?-source=VI/19GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table VI/19/gicfeige (Photoelectric Photometry of Giclas, Feige Stars)https://vizier.cds.unistra.fr/viz-bin/conesearch/VI/19/gicfeige?https://vizier.iucaa.in/viz-bin/conesearch/VI/19/gicfeige?http://vizieridia.saao.ac.za/viz-bin/conesearch/VI/19/gicfeige?GETtext/xml+votable180.050000true16.069124.234420.005555555555555556Cone search capability for table VI/19/selstars (Selected Area Stars)https://vizier.cds.unistra.fr/viz-bin/conesearch/VI/19/selstars?https://vizier.iucaa.in/viz-bin/conesearch/VI/19/selstars?http://vizieridia.saao.ac.za/viz-bin/conesearch/VI/19/selstars?GETtext/xml+votable180.050000true13.916660.604930.0055555555555555565/6486 7845 6/0 2 17526 17749 17750 17751 17790 17818 17840 17841 17843 17879 18028 18029 18132 18748 18779 18782 18801 18854 18860 18861 18862 19093 19095 19136 19138 19141 19970 21841 21844 21846 21901 21903 21914 22115 22120 22121 22869 22927 22938 22949 22960 23101 23139 23145 23147 23148 23150 23789 25598 25935 26018 26019 26024 26025 26174 26175 26260 26261 26678 26740 26808 26916 26961 26964 26965 27021 27023 27032 27034 27233 27234 27235 27238 27241 30042 30043 30121 30123 30124 30357 30359 30400 30440 30754 31064 31065 31139 31144 31145 311473.322582951404819e-19 3.852589004194616e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/VI/19?format=asciiOpticaldefaultVI/19/gicfeigePhotoelectric Photometry of Giclas, Feige StarsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIDStar Identificationsmeta.id;meta.maincharRA1975Right Ascension (1975) hourspos.eq.ra;meta.mainDE1975Declination (1975) degreespos.eq.dec;meta.mainVmagV Magnitudemagphot.mag;em.opt.VfloatB-V(B-V) Color Indexmagphot.color;em.opt.B;em.opt.VfloatU-B(U-B) Color Indexmagphot.color;em.opt.U;em.opt.BfloatNNumber of times star was observedmeta.numberintMNumber of nights star was observedmeta.numberinte_VmagV mean errormagstat.error;phot.mag;em.opt.Vfloate_B-V(B-V) mean errormagstat.error;phot.color;em.opt.Bfloate_U-B(U-B) mean errormagstat.error;phot.color;em.opt.UfloatremG[1/4]? Note number explained in gicnotes.datmeta.noteintnullable_RA.icrsRight ascension (ICRS) (computed by VizieR, not part of the original data)pos.eq.ranullableindexed_DE.icrsDeclination (ICRS) (computed by VizieR, not part of the original data)pos.eq.decnullableindexedVI/19/gicnotesGiclas and Fiege NotesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintremG[1/4]+= Note numbermeta.note;meta.mainintprimarycont[a] Continuation indicatormeta.notecharnoteText of notemeta.notecharVI/19/selstarsSelected Area StarsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintareaSelected Area Fieldobs.fieldintIDStar I.D.meta.id;meta.mainintRA1975Right Ascension (1975) hourspos.eq.ra;meta.mainDE1975Declination (1975) degreespos.eq.dec;meta.mainVmagV magnitudemagphot.mag;em.opt.VfloatB-V(B-V) indexmagphot.color;em.opt.B;em.opt.Vfloatu_B-VUncertainty flag (:) on B-Vmeta.code.error;phot.color;em.opt.BcharU-B(U-B) indexmagphot.color;em.opt.U;em.opt.Bfloatu_U-BUncertainty flag (:) on U-Bmeta.code.error;phot.color;em.opt.UcharNNumber of times star was observedmeta.numberintMNumber of nights star was observedmeta.numberinte_Vmag? V mean errormagstat.error;phot.mag;em.opt.Vfloatnullablee_B-V? (B-V) mean errormagstat.error;phot.color;em.opt.Bfloatnullableu_e_B-VUncertainty flag (:) on e_B-Vmeta.code.errorchare_U-B? (U-B) mean errormagstat.error;phot.color;em.opt.Ufloatnullableu_e_U-BUncertainty flag (:) on e_U-Bmeta.code.errorcharBSD?Bergedorfer Spektral Durchmusterung IDmeta.idintnullableSpBSD spectral typesrc.spTypecharremSA[1/32]? Note number explained in selnotes.datmeta.noteintnullable_RA.icrsRight ascension (ICRS) (computed by VizieR, not part of the original data)pos.eq.ranullableindexed_DE.icrsDeclination (ICRS) (computed by VizieR, not part of the original data)pos.eq.decnullableindexedVI/19/selnotesSelected Area NotesremSA[1/32]+= Note numbermeta.note;meta.mainintprimarynoteText of notemeta.notecharcont[abc] Continuation indicatormeta.notecharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintVI/19/spectralSpectral TypesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintareaSelected Area Fieldobs.fieldintIDStar I.D.meta.id;meta.mainintrem[*]Indicates special note on this starmeta.notecharSpMK Spectral typesrc.spTypecharVI/19/spnotesSpectral Type NotesIDStar I.D.meta.id;meta.mainintnoteNotemeta.notecharhyphen[-]Hyphenmeta.notecharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintareaSelected Area Fieldobs.fieldint