ADC/CDS Standard Document for Catalog:
/catalogs/2/2168/

1. Use the ADC Data Viewer Suite to visualize the data.
2. Get the data files via anonymous FTP. (See Note.)

II/168      Homogeneous Means in the UBV System (Mermilliod 1991)
================================================================================
Catalogue of Homogeneous Means in the UBV System
    Mermilliod J.C.
    <Institut d'Astronomie, Universite de Lausanne (1991)>
================================================================================
ADC_Keywords: Photometry, UBV

Description:
   The present catalog supersedes an earlier edition of Nicolet (1978).  It is
   a collection of weighted mean photoelectric values (V, B-V, U-B) for stars
   measured in the UBV system.  The mean values were computed by combining all
   individual measurements compiled in the catalog of Mermilliod (1987),
   except those that were clearly found to be erroneous for some reason or
   another.  Some newer observations compiled since 1987 are also included in
   the means.  The procedure for computing the homogeneous means involved the
   calculation of normal averages weighted by the number of observations in
   each list (unity when not published).  New weights are assigned based on
   the deviation of each value from the previous mean, then a new weighted
   mean is computed.  

   This technique is not as rigorous as that used by Nicolet (comparison 
   of each list with the standard system master list), but the latter 
   cannot often be realized effectively in practice, since many lists 
   do not contain enough stars in common with a standard list.  Also,
   there are now so many references (more than 1500) that it is not feasible
   to analyze each publication with respect to a standard list.  This edition
   of the catalog contains 92964 stars measured since the introduction of the
   UBV system in 1953.  The data included are star identification in the
   Geneva coded numbering system, double and variable codes, UBV data and
   their standard deviations, and number of observations.  A second file
   contains the definition of the coded numbering system.  

   The catalog was prepared at the Institut d'Astronomie de l'Universite de 
   Lausanne in Geneva.
  
File Summary:
--------------------------------------------------------------------------------
 FileName       Lrecl  Records   Explanations
--------------------------------------------------------------------------------
ReadMe             80        .   This file
ubvmeans.doc       72      100   Author's documentation
ubvmeans.dat       72    92964   Catalog Data
number.doc         80     2630   Numbering system documentation
--------------------------------------------------------------------------------

Byte-by-byte Description of file: ubvmeans.dat
--------------------------------------------------------------------------------
   Bytes Format  Units   Label      Explanations
--------------------------------------------------------------------------------
   1- 10  A10    ---     IDnum      Lausanne identification number 
                                    (Mermilliod 1978) 
      11  A1     ---     comp      *Lausanne component (D, 1, 2, ...). 
      12  A1     ---     var        Variability (V) code.
  14- 15  I2     ---     numpub     Number of publications (separate lists)
                                     contributing observations to the means
  17- 22  F6.3   mag     Vmean      ?Mean V magnitude (Precision varies)
  25- 29  F5.3   mag     Vsigma     ?Standard deviation for Vmean
      31  A1     ---     l_Vmean    [> ]Indicates more than o_Vmean 
                                     observations
  32- 34  A3     ---     o_Vmean   *[0-9 STD/] Number of observations for 
                                     Vmean  
  36- 41  F6.3   mag     B-Vmean    ?Mean (B-V) color index (Precision varies)
  44- 48  F5.3   ---     B-Vsigma   ?Standard deviation for B-Vmean
      50  A1     ---     l_B-Vmean  [>]Indicates more than o_B-Vmean
                                      observations
  51- 53  A3     ---     o_B-Vmean *[0-9 STD/] Number of observations for 
                                     B-Vmean
  55- 60  F6.3   mag     U-Bmean    ?Mean (U-B) color index (Precision varies)
  63- 67  F5.3   mag     U-Bsigma   ?Standard deviation for U-Bmean
      69  A1     ---     l_U-Bmean  [>]Indicates more than o_U-Bmean 
                                     observations
  70- 72  A3     ---     o_U-Bmean *[0-9 STD/] Number of observations 
                                     for U-Bmean  
--------------------------------------------------------------------------------
Note on IDnum,comp:
   The Lausanne identification number is comprised of both the IDnum and comp 
   fields. The "D" in the comp field indicates that more than one component 
   of a multiple system was included in the diaphragm when the observation 
   was made.
Note on o_Vmean,o_B-Vmean,o_U-Bmean:
   STD indicates standard star
   /   indicates number is unknown

References:
   Mermilliod, J.-C., & Mermilliod, M.: 1994, "Catalog of mean UBV 
     data on stars." Springer-Verlag, New York
   Mermilliod, J.-C. 1978, Bull. Inform. CDS No. 14, p. 32
   Mermilliod, J.-C. 1987a, A&AS, 71, 119
   Mermilliod, J.-C. 1987b, A&AS, 71, 413
   Mermilliod, J.-C. 1987c Bull. Inform. CDS No. 32, p. 37
   Mermilliod, J.-C., & Nicolet, B. 1977, A&AS, 29, 259
   Nicolet, B. 1978, A&AS, 34, 1
   Nicolet, B., & Hauck, B. 1977, in Compilation, Critical Evaluation and
     Distribution of Stellar Data, ed. C. Jaschek & G. A. Wilkins
     (Dordrecht, Reidel), p. 121
================================================================================
(End)                                 James E. Gass [SSDOO/ADC]  5-Sep-1997