J/AJ/107/230ivo://CDS.VizieR/J/AJ/107/230doi:10.26093/cds/vizier.51070230CDSALCAINO G.LILLER W.ALVARADO F.WENDEROTH E.2023-04-06T16:50:07Z1997-12-09T20:17:38ZCDS support team

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

cds-question@unistra.frglobular-star-clustersccd-photometryastrometryWe present BVRI photometry of three overlapping fields in the globular cluster NGC 1904 (M79), observed with a CCD camera and the 2.2m Max-Planck-Institute telescope at ESO/La Silla. We critically compare our photometry using the INVENTORY data reduction code with results derived by other investigators using different codes. These comparisons convince us that all modern codes give results reliable to at least +/-0.3mag at all levels, as long as the fields are not overly crowded. Specifically, our results for NGC 1904 (M79) are as follows: V(TO)=19.60+/-0.10 (estimated external error), with turnoff colors at B-V=0.40, V-R=0.27, V-I=0.57, and B-I=0.97, all with estimated external errors of +/-0.06. By fitting the four resulting ridge lines to the theoretical isochrones of VandenBerg & Bell [ApJS, 58, 561 (1985)] interpolated to [Fe/H]=-1.60, Y=0.20, and [O/Fe]=0.00, we derive an average value for the age of 16Gyr, where we have adopted E(B-V)=0.01. Addresses: Instituto Isaac Newton, Ministerio de Educacion de Chile, Casilla 8-9, Correo 9, Santiago, Chile1994AJ....107..230Ahttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/AJ/107/230CatalogResearchIsServedByTAP VizieR generic servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/AJ/107/230https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/AJ/107/230http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/AJ/107/230https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/AJ/107/230https://vizier.iucaa.in/viz-bin/votable?-source=J/AJ/107/230http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/AJ/107/230GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapOpticaldefaultJ/AJ/107/230/table6CCD coordinates, magnitudes, and colors for 750 stars in NGC 1904recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintStarStar numbermeta.id;meta.mainintn_StarAdditional note for Star (1)meta.notecharXX CCD coordinatepixpos.cartesian.x;instr.detfloatYY CCD coordinatepixpos.cartesian.y;instr.detfloatVmagV magnitudemagphot.mag;em.opt.VfloatB-V[]? B-V colormagphot.color;em.opt.B;em.opt.VfloatV-R[]? V-R colormagphot.color;em.opt.V;em.opt.RfloatR-I[]? R-I colormagphot.color;em.opt.R;em.opt.IfloatV-I[]? V-I colormagphot.color;em.opt.V;em.opt.IfloatB-I[]? B-I colormagphot.color;em.opt.B;em.opt.Ifloat