ACDS V10.0 - Sat Apr 27 06:40:53 CEST 2019
|  | Detailed Description of I/297 :
 NOMAD Catalog (Zacharias+ 2005)
 |  | 
Note : this is the description file of the original catalog.
This HTML page corresponds well to the original description, but some minor
changes in the format may have been introduced in the FITS output
files in order to allow for arithmetic operations on quantities
such as coordinates and times. h:m:s and d:m:s units are normally
converted into degrees, and YYYY-MM-DD into julian days.
Similarly, some slight changes may have been introduced in the
units; the value given in the HTML files supersedes the value indicated in the ReadMe
file for this catalogue.
I/297                     NOMAD Catalog                        (Zacharias+ 2005)
================================================================================
Naval Observatory Merged Astrometric Dataset (NOMAD)
     Zacharias N., Monet D.G., Levine S.E., Urban S.E., Gaume R., Wycoff G.L.
    <San Diego AAS Meeting, January (2005)>
    =2004AAS...205.4815Z
================================================================================
ADC_Keywords: Positional data ; Proper motions ; Surveys ;
              Photometry, photographic ; Photometry, infrared
Description:
    The  Naval Observatory Merged  Astrometric  Dataset  (NOMAD)  contains
    astrometric and photometric data for over 1 billion stars derived from
    the Hipparcos (I/239), Tycho-2 (I/259),  UCAC2 (I/289),  and USNO-B1.0
    (I/284)  catalogs for astrometry and optical photometry,  supplemented
    by 2MASS (II/246)  near-infrared photometry.  For each unique star the
    "best"   astrometric and photometric  data are chosen  from the source
    catalogs and merged into a single dataset. A sequence of priorities is
    followed  and NOMAD contains flags to identify the source catalogs and
    gives cross-reference identifications.  This first release of NOMAD is
    not a compiled catalog; that is,  if a star is identified in more than
    1 of the  above mentioned catalogs,   only 1 catalog  entry is chosen.
    Thus  the local  and global  systematic errors  of the  various source
    catalogs will be present in this version of NOMAD. All source catalogs
    astrometric  data are on the  International Celestial Reference System
    within the  limitations of the source  catalogs.
    For more information, see www.nofs.navy.mil/nomad
    A dedicated remote query program can be downloaded from
    http://cdsweb.u-strasbg.fr/doc/cdsclient.html
File Summary:
       FileName      Lrecl  Records   Explanations
×                   80        .   This file
× ReadMe            80        .   This file
× out.sam          167     1523   Example of the an output of NOMAD-1
See also:
    http://www.nofs.navy.mil/nomad : NOMAD Home Page
    I/239 : The Hipparcos and Tycho Catalogues (ESA 1997)
    I/259 : The Tycho-2 Catalogue (Hog+ 2000)
    I/284 : The USNO-B1.0 Catalog (Monet+ 2003)
    I/289 : UCAC2 Catalogue (Zacharias+ 2004)
   II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
Byte-by-byte Description of file:  out.sam
   Bytes Format Units    Label    Explanations
   1- 12  A12   ---      NOMAD1   NOMAD-identifier (1)
  14- 25  A12   ---      USNO-B1  Identifier in USNO-B1 (Cat. I/284) (1)
  27- 34  I8    ---      UCAC2    ? Number in UCAC2 (Cat. I/289)
  36- 47  A12   ---      Tycho-2  ? Identification in Tycho-2 or Hipparcos (2)
      48  A1    ---    f_Tycho-2  [*] when distance NOMAD1/Tycho-2 > 1arcsec
  49- 50  A2    ---      YM       [YM.] Existence in YB6 or 2MASS (Cat. II/246)
  52- 62  F11.7 deg      RAdeg    Right ascension in ICRS, Ep=J2000
  63- 73  F11.7 deg      DEdeg    Declination in ICRS, Ep=J2000
      75  A1    ---      r        [BCMYTH] Source of position (3)
  77- 80  I4    mas      e_RAdeg  Mean error on RAdeg (at epRA)
  82- 85  I4    mas      e_DEdeg  Mean error on DEdeg (at epDE)
  87- 94  F8.1  mas/yr   pmRA     Proper motion in RA (*cos(Dec))
  96-103  F8.1  mas/yr   pmDE     Proper motion in Declination
 105-109  F5.1  mas/yr   e_pmRA   Mean error on pmRA
 111-115  F5.1  mas/yr   e_pmDE   Mean error on pmDE
 117-122  F6.3  mag      Bmag     ?Blue magnitude
     123  A1    ---      r_Bmag   [BCMYTHo] Origin of Bmag (3)
 125-130  F6.3  mag      Vmag     ?Visual magnitude
     131  A1    ---      r_Vmag   [BCMYTH] Origin of Vmag (3)
 133-138  F6.3  mag      Rmag     ?Red magnitude
     139  A1    ---      r_Rmag   [BCMYTHe] Origin of Rmag (3)
 141-146  F6.3  mag      Jmag     ?Infrared J magnitude (from 2MASS)
 148-153  F6.3  mag      Hmag     ?Infrared H magnitude (from 2MASS)
 155-160  F6.3  mag      Kmag     ?Infrared K magnitude (from 2MASS)
 162-166  A5    ---      Xflags   [0-9a-f] Hexadecimal flags (4)
     167  A1    ---      R        [R*] Recommended (R) or Problematic (*) (4)
Note (1): NOMAD and USNO designations consist in 2 numbers
     separated by a dash of the form:  zone-number
     where zone (0000-1799) indicates a declination strip from the South
     Pole (0.1deg wide), and number is a sequential number increasing
     with right ascension.
Note (2): The Tycho-2 number (Cat. I/259) is made of 3 numbers separated
     by 2dashes, while Hipparcos (Cat. I/239) is a sequential number.
Note (3): Sources of the values are defined as follows:
      B = USNO-B1.0 (Monet et al., Cat. I/284)
      C = UCAC2 (Zacharias et al., Cat. I/289)
      M = 2MASS catalog of point sources (Cutri et al., Cat. II/246)
      Y = YB6 Catalog (USNO, unpublished)
      T = Tycho-2 Catalog (Hog et al., 2000, Cat. I/259)
      H = Hipparcos catalog (Table I/239/hip_main)
      o = Palomar-I blue (O) plate (for Bmag)
      e = Palomar-I red  (E) plate (for Rmag)
Note (4): Flags are written in hexadecimal (symbols 0-f) with the
          following meaning:
  00001 = UBBIT   : Fails Blaise's test for USNO-B1.0 star
  00002 = TMBIT   : Fails Roc's test for clean 2MASS star
  00004 = YB6     : Included in YB6 catalog (Y)
  00008 = 2MASS   : Included in 2MASS catalog (M)
  00010 = TYBIT   : Astrometry comes from Tycho2 catalog (T)
  00020 = XRBIT   : Alternative correlations for same (RA,Dec)
  00040 = ITMBIT  : Alternative correlations for same 2MASS ID
  00080 = IUCBIT  : Alternative correlations for same UCAC-2 ID
  00100 = ITYBIT  : Alternative correlations for same Tycho2 ID
  00200 = OMAGBIT : Blue magnitude from O (not J) plate (o)
  00400 = EMAGBIT : Red magnitude from E (not F) plate (e)
  00800 = TMONLY  : Object found only in 2MASS catalog (M)
  01000 = HIPAST  : Ast from Hipparcos catalog (H)
  02000 = SPIKE   : USNO-B1.0 diffraction spike bit set
  04000 = TYCONF  : Tycho2 confusion flag set
  08000 = BSCONF  : Bright star has nearby faint source
  10000 = BSART   : Faint source is bright star artifact
  20000 = USEME   : Recommended astrometric standard
      * = one of SPIKE|YCONF|BSCONF|BSART|XRBIT|ITMBIT|IUCBIT|ITYBIT set
      R = USEME (recommended astrometric standard)
History:
    Prepared by Dave Monet.
Acknowledgements:
    It is a pleasure to thank Dave Monet who forwarded a copy of the
    NOMAD catalog to CDS.
================================================================================
(End)                                   Francois Ochsenbein [CDS]    09-Nov-2005