J/A+AS/116/403ivo://CDS.VizieR/J/A+AS/116/403CDSFiorucci M.Tosti G.1997-12-09T18:05:51Z1997-12-09T19:05:48ZCDS support team

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

cds-question@unistra.frbl-lacertae-objectsinfrared-photometryvisible-astronomyphotometryWe present VR_cI_c Johnson-Cousins magnitudes of field comparison stars for twelve BL Lacertae objects belonging to the more large sample of blazars which is monitored at Perugia Astronomical Observatory. These comparison stars can be used in the long-term CCD photometric monitoring of BL Lac objects aimed to understand the characteristics of their variability. Finding charts for all of these comparison sequences are also included in this paper. For a description of the (RI)c photometric system, see e.g. the General Catalog of Photometric Data <GCPD/54>1996A&AS..116..403Fhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+AS/116/403CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+AS/116/403https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+AS/116/403http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+AS/116/403https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+AS/116/403https://vizier.iucaa.in/viz-bin/votable?-source=J/A+AS/116/403http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+AS/116/403GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+AS/116/403/table3 (VR_c_I_c_ comparison stars in the fields of BL Lacertae objects)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+AS/116/403/table3?https://vizier.iucaa.in/viz-bin/conesearch/J/A+AS/116/403/table3?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+AS/116/403/table3?GETtext/xml+votable180.050000true35.66543.0355560.005555555555555556https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+AS/116/403?format=asciiOpticalInfrareddefaultJ/A+AS/116/403/table3VR_c_I_c_ comparison stars in the fields of BL Lacertae objectsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameNames of BL Lac objects and respective comparison starsmeta.id;meta.maincharRA2000Right ascension (2000)pos.eq.ra;meta.mainDE2000Declination (2000)pos.eq.dec;meta.mainVmag? V Johnson magnitudemagphot.mag;em.opt.Vfloate_Vmag? Standard deviation on V magnitudemagstat.errorfloatRcmag? Cousins R magnitudemagphot.mag;em.opt.Rfloate_Rcmag? Standard deviation on R_c_ magnitudemagstat.errorfloatIcmag? Cousins I magnitudemagphot.mag;em.opt.Ifloate_Icmag? Standard deviation on I_c_ magnitudemagstat.errorfloatNumber? Number of nights utilized to calibrate each starmeta.numberintReferReferences for those objects that have previously published photometric sequences in at least one of the VRI filters (1)meta.refchar