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II/118      UBVRI Photometric Standard Stars, Celestial Equator (Landolt 1983)
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UBVRI Photometric Standard Stars Around the Celestial Equator
    Landolt A.U.
    <AJ, 88, 439 (1983)>
    =1983AJ.....88..439L
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ADC_Keywords: Photometry, UBVRI ; Stars, standard ; Stars, equatorial

Description:
   The catalog contains UBVRI photoelectric observations of 223 stars,
   mostly in an approximately 2-degree zone centered on the celestial
   equator. The catalog is intended to provide a uniform set of new
   standards, available to various sizes of telescopes in both hemispheres,
   on an internally consistent, homogeneous system. Most of the stars are
   in Selected Areas 92-115 and fall in the magnitude range of about 7 to
   12.5 in V and color range -0.3 to +2.0 in B-V. The data include
   equatorial coordinates, photoelectric magnitudes and colors, numbers of
   observations, and computed internal errors.

File Summary:
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 FileName       Lrecl  Records   Explanations
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ReadMe             80        .   This file
doc.txt            79      336   ASCII version of ADC doc. (more detailed)
doc.tex            79      300   LaTeX version of ADC document
adc.sty            78       38   ADC Style File
standard.dat      125      223   Catalog Data
notes.txt         132      227   Remarks
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Byte-by-byte Description of file: standard.dat
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   Bytes  Format  Units   Label    Explanations
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   1-  2   A2     ---     cat      Catalog abbreviation
   3- 10   A8     ---     ID       Number in catalog
      11   A1     ---     supp     [a ] BD supplement letter (Barnard star)
  13- 14   I2     h       RAh     *Right ascension hours (1985.0)
  16- 17   I2     min     RAm     *Right ascension minutes (1985.0)
  19- 20   I2     s       RAs     *Right ascension seconds (1985.0)
      22   A1     ---     DE-      Sign of declination
  23- 24   I2     deg     DEd     *Declination degrees (1985.0)
  26- 27   I2     arcmin  DEm     *Declination degrees (1985.0)
  29- 30   I2     arcsec  DEs     *Declination degrees (1985.0)
  32- 37   F6.3   mag     V       *V magnitude
  39- 44   F6.3   mag     B-V      B-V color
  46- 51   F6.3   mag     U-B      U-B color
  53- 58   F6.3   mag     V-R      V-R color
  60- 65   F6.3   mag     R-I      R-I color
  67- 72   F6.3   mag     V-I      V-I color
  74- 75   I2     ---     o_V      Number of observations in weighted means
  77- 78   I2     ---     no_V     Number of nights on which star was observed
  81- 86   F6.4   mag     e_V     *Mean error of V
  88- 93   F6.4   mag     e_B-V    Mean error of B-V
  95-100   F6.4   mag     e_U-B    Mean error of U-B
 102-107   F6.4   mag     e_V-R    Mean error of V-R
 109-114   F6.4   mag     e_R-I    Mean error of R-I
 116-121   F6.4   mag     e_V-I    Mean error of V-I
 123-125   A3     ---     n_V     *Note flag(s)
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Note on RA* and DE*:
   Positions are for equinox 1985 at epoch. However, proper motions have
   been accounted for in computing the 1985 coordinates for the large
   proper-motion stars, so these positions are given for equinox and epoch
   1985.0.
Note on V:
   Weighted V magnitude on the UBVRI photometric system, as defined by
   stars in Landolt (1973) and Cousins (1976). The colors are similar
   weighted means.
Note on e_V:
   The mean error of a single observation of V or a color can be found by
   multiplying the appropriate error of the mean by the square root of n.
Note on n_V:
   Number(s) referring to notes given at the top of the remarks file. These
   notes are distinct from the additional information given in Appendix I,
   which follows the "Notes" section in notes.txt.

History:
   The machine-readable data table UBVRI Photometric Standards Around the
   Celestial Equator was received on magnetic tape from Dr. Arlo U. Landolt
   on 15 April 1986. Various modifications were made by Wayne. H. Warren at
   the ADC in order to effect a uniformly formatted data file, to isolate
   the table notes from the data, and to add the additional information
   contained in Appendix I of the published paper.

Acknowledgments:
   Warren expressed appreciation to A. U. Landolt for providing the catalog
   on magnetic tape and for reviewing and commenting on a preliminary
   version of this document prior to its finalization for distribution with
   the machine-readable catalog. This document has been derived from
   doc.txt.

References:
   Cousins, A. W. J. 1976, Mem. Roy. Astron. Soc. 81, 25-36.
   Landolt, A. U. 1973, Astron. J. 78, 959-981.
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(End)        N. G. Roman          [SSDOO/ADC]       May-27-1997