[vsnet-chat 2167] Cordoba to GSC matching

[bas@lowell.Lowell.Edu (Brian Skiff)]

     It is straightforward but tedious to match any two catalogues using
the Strasbourg VizieR service.  The procedure would be "simply" to make a
file on your local machine of, for instance, the Cordoba catalogue, and using
the match-against-list feature in VizieR, run it against the GSC v1.2.  The
reasons this is not truly "simple" include the sheer number of stars (about
600,000), and the large number of special cases one will run into.  If you
want to do this right, so that no one will have to do it again, those special
cases must be dealt with one at a time.  Perhaps one approach would be to
make a pass thourgh the list and set aside the highly-certain match-ups, which
will be at least 90 percent of the cases, then make a separate list where
there are ambiguities that need to be looked at carefully using photometry,
spectral types, proper motion, DSS images, etc.
     Here is an example of the net output from VizieR for the sixteen CoD
stars of -89 zone versus GSC v1.2.  The positions are from GSC v1.2.  Because
the field is uncrowded there were no ambiguities here, the CoD positions all
being within 6" of the GSC v1.2.  This will certainly not be the case along the
galactic plane!  As you can see by my subsequent comparison in SIMBAD, each of
the stars is already in SIMBAD.  (The southern Cordoba zones were published
much later than the northern parts, and are not so complete.)  However, not all
the CoD names are included there.  In addition, there is a new identification,
whereby the red variable BQ Oct is shown in two entries in SIMBAD.  I'll report
this to the Strasbourg folks, so this will be taken of soon.



CoD      offset     RA   (2000)   Dec         GSC      SIMBAD
          (")
-89  1    1.5     0 12 31.09  -88 21 48.0  9502-0209   HD 1348
          2.8     0 12 33.93  -88 21 46.5  9502-0209
-89  2    3.9     0 33 53.85  -88 37 19.9  9502-0349   HD 5325
-89  3    2.5     0 48 49.82  -88 24 53.0  9502-0208   HD 7296
-89  4    3.8     1 07 28.87  -88 27 28.1  9502-0221   HD 10522
-89  5    5.5     0 45 23.88  -89 10 08.4  9502-0053   HD 12697
-89  6    1.5     2 09 19.13  -89 08 12.8  9503-0307   HD 29328
-89  7    3.4     4 52 20.88  -89 16 26.3  9504-0318   HD 63013
-89  8    3.4     8 58 35.02  -89 49 52.3  9518-0405   HD 98784
-89  9    3.3     9 56 42.91  -89 46 56.7  9518-0379   HD 99685
-89 10    2.5    14 35 26.74  -89 46 18.2  9521-0302   HD 110994 = BQ Oct
          2.7    14 35 25.73  -89 46 17.6  9521-0302   
-89 11    2.8    23 03 10.24  -89 39 40.9  9537-0207   HD 116751
-89 12    5.5    19 54 09.13  -89 16 16.6  9535-0263   HD 151667
-89 13    4.5    21 08 46.44  -88 57 23.4  9536-0384   HD 177482 (sigma Oct)
-89 14    2.6    22 23 40.45  -88 53 43.1  9537-0171   HD 199624
-89 15    3.9    22 45 28.53  -88 49 06.1  9537-0348   HD 206553 (CG Oct)
          6.1    22 45 37.21  -88 49 06.2  9537-0348   
-89 16    2.5     0 00 49.70  -88 19 42.0  9502-0308   HD 224697



New SIMBAD ID:  V* BQ Oct = S1* 453



\Brian

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