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*                Documentation for ZC Tycho2                 *
*                                                            *
*                         D Herald                           *
*                         May 2003                           *
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  This version of Robertson's Zodiacal catalogue was generated as a peripheral
part of the development of the XZ80Q catalogue. This version of the ZC catalogue
is based on the Hipparcos and Tycho-2 catalogues.


1.   Generating the catalogue

     The catalogue was generated in the following manner:

a.   All entries in the XZ80Q catalogue having a ZC identifier were extracted.
   NOTE: This occurred before UCAC positions were added to XZ80Q - so that the
   positions in this version of the ZC catalogue are either Hipparcos, or Tycho-2 
   position. The XZ number of these stars is given in the last field of
   each record.

b.   The XZ80Q eliminated 5 ZC stars on the basis that their ecliptic latitude
   was greater than 7d. The details for these stars were copied from XZ80P, where
   Hipparcos positions were available for all 5 stars. The XZ number of these
   stars is given in the last field of each record, with an asterisk '*'
   preceding 'XZ'

c.   295 ZC stars have never been included in the XZ catalogues. Positions for
   288 of these were extracted from the Hipparcos catalogue. The remaining 7 
   were extracted from the Tycho-2 catalogue. No XZ number is given for
   these stars. Also, no attempt has been made to include BD numbers, and other
   cross-references, for these stars.



2.   Format of the Catalogue

     The format of the catalogue is the same as for XZ80Q, except for the 
  record length, and last field.

     The catalogue is formatted with a fixed record length of 206 characters,
with characters 205/206 being a Carriage Return / Line Feed sequence. A 
record exists for all possible ZC numbers, so that the record number is the 
same as the ZC number.
 
     A byte-by-byte description of the ZC Tycho2 catalog is given below.  The
Format column gives the field format in Fortran notation, as for XZ80P.

Byte(s): (Format) Description
  1-  2: (A2) 'ZC'
  3-  6: (I4) [1-3539] ZC number
  7-  8: (A2) [BD,SD,CD,CP] Durchmusterung (DM) identifier
  9- 17: (A1,I2,I5,A1) DM zone and number
     18: (A1) [CcDdWwMS] Double star code (DSC), with the following meaning
               C = double, component in XZ80Q, Separation <1"
               c = double, component not in XZ80Q, Separation <1"
               D = double, component in XZ80Q, Separation <10"
               d = double, component not in XZ80Q, Separation <10"
               W = double, component in XZ80Q, Separation >10"
               w = double, component not in XZ80Q, Separation >10"
               M = multiple system, all components in XZ80Q
               S = multiple system, some but not all in XZ80Q
     19: (A1) [EeVvSs] Variable star code, with the following meaning
               E = eclipsing-type variable, magnitude variation >0.5 mag
               e = eclipsing-type variable, magnitude variation <0.5 mag
               V = other variable, magnitude variation >0.5 mag
               v = other variable, magnitude variation <0.5 mag
               S = suspected variable, magnitude variation >0.5 mag
               s = suspected variable, magnitude variation <0.5 mag
 20- 24: (F5.2) V magnitude
     25: (A1) [ THX] V magnitude source flag
              (blank= Johnson V from HIP, T= Johnson V computed
               from VTmag and BTmag from TYC, H= Hpmag from HIP, 
               X= visual from XZ80N)
 26- 36: (I2,I2,F7.4) Right ascension (hms), epoch and equinox J2000.0,
              ICRS for HIP and ACT stars, FK5 for others
 37- 44: (F8.4) Proper motion in right ascension (s/cy)
 45- 55: (A1,I2,I2,F6.3) Declination (d'"), epoch and equinox J2000.0,
              ICRS for HIP and ACT stars, FK5 for others
 56- 63: (F8.3) Proper motion in declination ("/cy)
 64- 66: (F3.0) Trigonometric parallax (mas)
     67: (A1) [ X] Trigonometric parallax source flag
              (blank= from HIP, X= from XZ80N)
 68- 73: (F6.1) Radial velocity (km/s)
     74: (A1) [ X] Radial velocity source flag
              (blank= form HIC, X= from XZ80N)
 75- 78: (F4.0) Standard error in RA*cos(Dec) at source epoch (mas)
 79- 82: (F4.0) Standard error in PM in RA at source epoch (mas/cy)
 83- 86: (F4.0) Standard error in Dec at source epoch (mas)
 87- 90: (F4.0) Standard error in PM in Dec at source epoch (mas/cy)
 91- 97: (F7.2) Source epoch (yr)
 98-102: (F5.2) B magnitude
    103: (A1) [ B] B magnitude source flag
               (blank= Johnson B from HIP, B= Johnson B computed
               from VTmag and BTmag from TYC)
104-115: (A12) Spectral type
    116: (A1) [ X] Spectral type source flag
              (blank= from HIP, X= from XZ80N)
117-129: HIP number and flags, TYC ID, or UCAC1 ID
   For HIP stars
        117: (A1) 'H'
    118-123: (I6) [1-120416] HIP number
        125: (I1) [1-4] Sequential number for the same HIP number
                  given in HIP double/multiple systems annex
                  [5-8] 5 = 1+2; 6 = 1+3; 8 = 2+3 
        126: (I1) [1-4] Number of stars with the same HIP number
                  given in HIP double/multiple systems annex
                  (bytes 125-126 are given for stars of byte 127=C)
        127: (A1) [CGOVX] Double/multiple systems flag indicating
                  further details are given in HIP annex:
                  C= solutions for the components
                  G= acceleration or higher order terms
                  O= orbital solutions
                  V= variability-induced movers
                  X= stochastic solution
        128: (A1) [FIL] Type of solution:
                  F= fixed double or multiple system
                     (identical proper motions and parallaxes),
                  I= individual parallaxes and linear (relative)
                     motion (possible optical double star)
                  L= linear double or multiple system
                     (may have different proper motions but
                      assumed to have same parallax)
        129: (A1) [ABCDS] Double/multiple star solution quality
                  (A=good, B=fair, C=poor, D=uncertain,
                   S=suspected non-single)
   For TYC stars
        117: (A1) 'T'
    118-129: (A12) TYC ID [rrrr-nnnnn-c] where rrrr is the GSC region,
                    nnnnn is the GSC number in the region, and c is the
                    component number.
130-139: (A10) CCDM identifier
140-141: (A2) CCDM component identifiers
142-147: (I6) SAO number
148-151: (I4) ZC number
152-157: (I6) PPM number
158-166: (A1,I2,I5,A1) AGK number
167-172: (I6) HD number
173-177: Flags for HIP and TYC stars
   For HIP stars (these are not given for components of
                  double/multiple stars)
        175: (A1) [CDMPRU] Variability type:
                  C= no variability detected ("constant")
                  D= duplicity-induced variability
                  M= possibly micro-variable (amplitude < 0.03mag)
                  P= periodic variable
                  R= V-I color index was revised due to variability
                     analysis
                  U= unsolved variable which does not fall in the
                     other categories
        176: (A1) [12] Additional data about variability given in
                  HIP annex
   For TYC stars
        173: (A1) [ X] Reference flag for astrometry:
                  blank= a recommended astrometric reference star
                  X= a dubious astrometric reference star in TYC
        174: (I1) [1-9] Astrometric quality flag:
                  1 through 5= very high to medium quality;
                     probably single stars
                  6= perhaps non-single
                  7= low astrometric quality
                  8= perhaps non-stellar
                  9= very low astrometric quality
        175: (A1) [GN] Known variability from GCVS/NSV:
                  G= star in General Catalogue of Variable Stars,
                     4th Edition
                  N= star in New Catalogue of Suspected Variable Stars
        176: (A1) [UVW] Variability from TYC:
                  U= apparent variability in TYC data;
                     may be due to duplicity
                  V= strong evidence of variability in the TYC data
                  W= variability suspected in the TYC data
        177: (A1) [DRSYZ] Duplicity from TYC:
                  D= duplicity clearly indicated
                     (BTmag and VTmag refer to combined light)
                  R= duplicity weakly indicated,
                     combined with indication of variability
                  S= duplicity suspected
                  Y= investigation of duplicity made,
                     no indication of duplicity
                  Z= no investigation of duplicity was performed
178-179: (I2) Source code for position and proper motion:
         01= HIP
         11= Tycho-2
         12= Tycho-2 - with proper motion being for the mean position
                       of a close pair
         13= Tycho-2 - with no proper motion. Position is for epoch
         14= Tycho-2 Supplement 1
  
180    : (A1) [N] Flag for existence of names for the star in XZStarNames.dat
                blank= no star name
                N= star name(s) in XZStarNames.dat file
181    : (A1) '*' if the star is in XZ80P, but excluded from XZ80Q because its
                  latitude was > 7d.
182-183: (A2) 'XZ' if the star is in the XZ80Q catalogue
184-189: (I6) Number in XZ80Q catalogue
205-206:      CR/LF sequence



D Herald
29 May 2003