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SAO - Smithsonian Astrophysical Observatory Star Catalog

HEASARC
Archive

Overview

This database is based on the electronic version of the SAO catalog from the Astronomical Data Center, which is itself based on an original binary version of the Smithsonian Astrophysical Observatory Star Catalog (SAO, SAO Staff 1966). Subsequent improvements by T. A. Nagy (1979) included the addition of cross-identifications from the Table of Correspondences SAO/HD/DM/GC (Morin 1973). As a prelude to creation of the 1984 version of the SAO, a new version of the SAO-HD-GC-DM Cross Index was prepared (Roman, Warren, and Schofield 1983). The 1984 version of the SAO contained the corrected and extended cross identifications, all errata published up to January 1984 and known to the ADC, numerous errors forwarded to the ADC by colleagues, and errors discovered at the ADC during the course of this work. Clayton A. Smith of the U. S. Naval Observatory provided J2000.0 positions and proper motions for the SAO stars. Published and unpublished errors discovered in the previous version (1984) have been corrected (up to May 1991).

For this HEASARC representation, some parameters such as the RA and Dec in radians have been omitted.


Catalog Bibcode

<I/131A/sao>

References

   Smithsonian Astrophysical Observatory Star Catalog
    SAO Staff  <Smithsonian Astrophysical Observatory (1966)>
   Morin, D. 1973, Table of Correspondences SAO/HD/DM/GC, Obs. de Meudon,
      unpublished                                       =IV/12
   Nagy, T.A. 1979, Documentation for the Machine-Readable Version of the
      Smithsonian Astrophysical Observatory Catalog(ue) (EBCDIC Version),
      Systems and Applied Sciences Corporation R-SAW-7/79-34
   Roman, N.G., Warren Jr., W.H., and Schofield Jr., N.J. 1983, Documentation
      for the Machine-Readable Version of the SAO-HD-GC-DM Cross Index,
      Version 1983, NSSDC/WDC-A-R&S 83-17

Provenance

This online version of the SAO Catalog was created by the HEASARC in March 2001 based on ADC/CDS Catalog I/131A, which itself is originally derived from a character-coded machine-readable version of the Smithsonian Astrophysical Observatory Star Catalog (SAO, SAO Staff 1966) prepared by T.A. Nagy in 1979, and subsequently modified over the next decade or so. The first machine-readable version contained format modifications, cross identifications and other changes, and was the starting point of the version in this database. Additional changes were made to the SAO catalog over time (namely more cross identifications and corrections) which resulted in a new version in 1984. Finally, the most recent version of the catalog was published in 1989. It included J2000 positions for all the objects, and corrections to errors known as of May 1989.

Deleted Entries

53 entries marked as duplicates were removed from the HEASARC online version of the SAO Catalog. The SAO numbers of these deleted duplicates are as follows:
SAO 9949     SAO 24671    SAO 31219    SAO 58906    SAO 67452    SAO 92316
SAO 96663    SAO 100161   SAO 106477   SAO 133461   SAO 142402   SAO 172631
SAO 180619   SAO 181584   SAO 186717   SAO 192426   SAO 193213   SAO 193858
SAO 193896   SAO 201604   SAO 210293   SAO 210294   SAO 215182   SAO 216112
SAO 217746   SAO 218092   SAO 218513   SAO 219513   SAO 222076   SAO 222287
SAO 224194   SAO 225327   SAO 226938   SAO 227039   SAO 228027   SAO 228854
SAO 229059   SAO 229831   SAO 231638   SAO 231703   SAO 232935   SAO 234389
SAO 235962   SAO 235973   SAO 236668   SAO 238177   SAO 238511   SAO 240305
SAO 241167   SAO 241172   SAO 242605   SAO 242962   SAO 246009

Parameters

Name
The primary name given is the SAO number, a sequence number prefixed with 'SAO '.

RA
The Right Ascension in the selected equinox. This was given to a precision of 0.001 seconds of time in the originating table, and in both B1950 Equator and Epoch, and J2000 Equator and Epoch. For the Web Browse version of this database, we have ingested the J2000 Equator and Epoch position since this is its default equator, while for the xray account Browse version, we have ingested the B1950 Equator and Epoch position, since this is its default equator. While the HEASARC Browse systems do have built-in precession routines, they are not of astrometric accuracy and they do not include the effects of proper motion, and thus set the equinox to the particular default specified above to retain the full positional accuracy.

Proper_Motion_RA
The annual Proper Motion in the RA direction on the FK4 System, in seconds of time per annum (year).

Proper_Motion_RA_Error
The standard deviation in the Proper Motion in the RA direction on the FK4 System, in milliarcseconds per annum (year).

RA_Epoch
The Original Epoch of RA2 in years. All epochs lie between 1875 and 1955.

Dec
The Declination in the selected equinox. This was given to a precision of 0.01 arcseconds in the originating table, and in both B1950 Equator and Epoch, and J2000 Equator and Epoch. For the Web Browse version of this database, we have ingested the J2000 Equator and Epoch position since this is its default equator, while for the xray account Browse version, we have ingested the B1950 Equator and Epoch position, since this is its default equator. While the HEASARC Browse systems do have built-in precession routines, they are not of astrometric accuracy and they do not include the effects of proper motion, and thus set the equinox to the particular default specified above to retain the full positional accuracy.

Proper_Motion_Dec
The annual Proper Motion in the Declination direction on the FK4 System, in arcseconds per annum (year).

Proper_Motion_Dec_Error
The standard deviation in the Proper Motion in the Declination direction on the FK4 System, in milliarcseconds per annum (year).

Dec_Epoch
The Original Epoch of Dec2 in years. All epochs lie between 1875 and 1955.

Position_Error
The standard deviation of the position at epoch 1950.0, in units of arcseconds (converted from the units of 10 milliarcseconds that were used in the CDS/ADC table).

LII
The Galactic Longitude.

BII
The Galactic Latitude.

Pg_Mag
The photographic magnitude.

Vmag
The visual magnitude.

Spect_Type
The (one-dimensional) spectral type, where '+++'indicates that the spectrum was either composite, varying, or peculiar.

Ref_Vmag
A reference code for the source of the visual magnitude, as below. Always check the duplicity/variability code given in the remarks parameter when using magnitudes.

           Photo-
    Visual visual Magnitude source

      0           Does not appear in source catalog
      1      21   Determined by source catalog
      2      22   Determined by source catalog or by authority in footnote
      3      23   Source cited in source catalog introduction
             24   Source unspecified
      5           Taken from "Bonner Durchmusterung"
      8           Based on Durchmusterung magnitudes and visual estimates
      9           Taken from AGK1
     10           Taken from Cordoba Zones (Resultados)
     12           Taken from CGA (Perrine 1911a, b) or Cordoba Zones
     13           Taken from Harvard publications
     14           Taken from Harvard or San Luis photometry
     15           Taken from the "Henry Draper Catalogue"
     16           Combined magnitude of component stars
     17           Arithmetic mean of maximum and minimum magnitudes of a
                    variable star
  

Ref_Star_Number
A reference code for the source of the star numbers and footnotes information as follows:

      Footnote
    without with  Star Number

      0      16   Source catalog only
      1      17   Source catalog and BD
      2      18   Source catalog and CD
      3      19   Source catalog and CPD
      4      20   Cordoba B (Resultados) and CD
      5      21   Cordoba A (Resultados) and CD
      6      22   AGK1 and BD
      7           GC and BD
      8      24   Cordoba B (Resultados) and CPD
      9           Cordoba A (Resultados) and CPD
  
When blank, the code for DM is 0 or 16, footnote is 0 through 9, and field is all zeros. Footnotes and star numbers are those appearing in the source catalogs.

Ref_Pg_Mag
A reference code for the source of the photographic magnitude:

    Code  Source

      0   Does not appear in source catalog
      1   Determined by source catalog
      4   Taken from magnitudes of the CPD and diameters
          of the  Cape Astrographic Catalogue
      8   Source cited in source catalog introduction
      9   Columbia Contributions Numbers 30 and 31
          (Schilt and Hill 1937, 1938)
  
When blank, code is 0 and field is all zeros.

Ref_Proper_Motion
A reference code for the source of the proper motions:

    Code  Source

      1   Determined by source catalog
      3   Determined by comparison of catalog and Greenwich AC
      5   Determined by comparison of catalog and AGK1
      6   Determined by comparison of catalog and Greenwich AC
          on the basis of the smallest difference in positions
          (see page xiii of source reference)
      8   Determined by comparison of catalog and AGK1 on the
          basis of the smallest difference in positions
          (see page xiii of source reference)
  

Ref_Spect_Type
A reference code for the source of the spectral types:

    Code  Source
    ----------------------------------------------------------
      0   Taken from the Henry Draper Catalogue or no
          spectrum in source catalog
      1   Taken from the HD with M stars reclassified by Miss Cannon
      2   Classified by G. G. Cillie
      3   Classified by Goedicke
      4   Classified by D. Hoffleit
      5   Classified by M. W. Mayall
      6   Classified at Leander McCormick Observatory
      7   Classified by Nassau and Seyfert
  
If the spectrum is composite, "+++" is stored in the field and the code is 0.

Remarks
A referenc code for miscellaneous remarks on duplicity and variability:

    Code  Meaning

      0   No additional information
      1   Double star - see source catalog for source
      2   Double star in Aitken's Double Star Catalogue
          (Aitken 1932)
      3   Double star in Burnham's Double Star Catalogue
          (Burnham 1906)
      4   Variable star in visual magnitude in source catalog
      5   Variable star in photographic magnitude in source catalog
      6   Variable star in both magnitudes
      7   Both double and variable, in either visual or
          photographic magnitudes
  
When blank, code is 0, no field is involved.

Ref_Source_Cat
A reference code for the specific source catalog:

           No.      Abbreviated Title

           01       AGK2, Volume 1
           02       AGK2, Volume 2
           03       AGK2, Volume 5
           04       AGK2, Volume 6
           05       AGK2, Volume 7
           06       AGK2, Volume 8
           20       Yale Transactions 11
           21       Yale Transactions 12   Part I
           22       Yale Transactions 12   Part II
           23       Yale Transactions 13   Part I
           24       Yale Transactions 13   Part II
           25       Yale Transactions 14
           26       Yale Transactions 16
           27       Yale Transactions 17
           28       Yale Transactions 18
           29       Yale Transactions 19
           30       Yale Transactions 20
           31       Yale Transactions 21
           32       Yale Transactions 22   Part I
           33       Yale Transactions 22   Part II
           34       Yale Transactions 24
           35       Yale Transactions 25
           36       Yale Transactions 26   Part I
           37       Yale Transactions 26   Part II
           38       Yale Transactions 27
           40       Cape Annals 17
           41       Cape Annals 18
           42       Cape Annals 19
           43       Cape Annals 20
           48       Cape Zone
           60       Melbourne 3
           61       Melbourne 4
           70       GC
           71       FK3
           74       FK4
  

Num_Source_Cat
The star number in the specific source catalog specified in the ref_source_cat parameter.

DM
The Durchmusterung identification (BD, CD, or CP number), and component identification if there are two or more SAO stars having the same DM number.

HD
The Henry Draper Catalog (HD or HDE) Number.

HD_Component
The HD component and multiple code:

    Code   Meaning

      0    Single star or primary with a companion > 0.3 mag
           (visual) fainter.
      1    Brighter component with a companion <= 0.3 mag fainter.
      2    Fainter component with a companion <= 0.3 mag brighter.
      9    The "SAO Catalog" entry refers to two consecutive
           HD numbers, the lower of which is given.
  

Gc
The Boss General Catalog (GC) Number.

Proper_Motion_RA_FK5
The annual Proper Motion in the RA direction on the FK5 System, in seconds of time per annum (year).

Proper_Motion_Dec_FK5
The Annual Proper Motion in the Declination direction on the FK5 System, in arcseconds per annum (year).

Class
The HEASARC Browse object classification, based on the spectral type contained in the spect_type parameter.


Contact Person

Questions regarding the SAO database table can be addressed to the HEASARC User Hotline.

Page Author: Browse Software Development Team
Last Modified: 8-Nov-2004