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database stuffing finished, UBVRI vs. Dayton mags, etc.




  This brief note mentions several items.

     1. The database is stuffed -- but it may not be very useful yet.
        I'm currently running a procedure which will calculate the 
        mean magnitude in V and I for all stars observed at least
        10 times.  That table will be the one to query most often,
        I think.
     
     2. I tested the "chart-generation" software, and it does a fair
        job.  It does require the table with mean V and I magnitudes,
        so it won't be ready for use until Saturday or Sunday. 
        
     3. After I made a sample chart, I noticed that there are still
        some entries in the "tass_cat" table which belong to the
        same actual star -- that is, the table contains 2 entries,
        with nearly the same position and catalog.  I'll have to 
        come up with some way of merging these entries later.
 
        Using a catalog "seed" will avoid this problem, I think.

     4. I made a plot of (RA, Dec) for 1 of every 50 stars in the catalog.
        Look at the "Pretty Pictures" section of the TASS home page.

              http://a188-l009.rit.edu/tass/pretty.html
 
        I get the feeling I've omitted some of the TASS datafiles 
        which people have sent to me.  There's a huge gap between
        RA = 196 degrees and RA = 254 degrees -- a section of the
        sky which passes over the meridian in October and November.
        
        When I look at TN 41, I see that Glenn's data, alone, has a 
        number of observations in this area.  I must have failed to
        import some of his data.  Rats.

     5. Glenn asked about the offset I find between magnitudes of 
        stars in the Dayton compilation and magnitudes in Arne
        Henden's "UBVRI" catalog.  I may be using a larger version
        of the UBVRI catalog than Glenn.  I append below the
        comparison, for all 18 stars in common.

     6. Arne warns us not to claim to have discovered variable stars
        prematurely.  I agree.  I was going to start with candidates
        from the Dayton data and see if there were other observations
        from other sites which I could add to the candidate light
        curves ... but now it looks like I may have to import some
        more data instead.  Sigh.

        I'll produce a list of candidates, with (RA, Dec) positions
        and some sample data in tabular form, by the end of today.
        

  That's all for now.

                                                 Michael Richmond

 
 -------------------- comparison Dayton vs. UBVRI follows ----------------- 

       Pairs of objects within 15 arcsec of each other from

         A.  Arne Henden's "UBVRI" catalog (version with 730 stars)
         B.  Glenn Gombert's "photom3.out" catalog (92512 stars)

       18 pairs:  difference in V-band: mean = 0.24 mag, stdev = 0.64
                                I-band: mean = 0.52 mag, stdev = 0.95

       Of the 18 pairs, 7 have absolute value of (deltaV) <= 0.10 mag
                        5 have absolute value of (deltaI) <= 0.10 mag

       The "pos" lines below contain information on
              - difference in RA (arcsec)
              - difference in Dec (arcsec)
              - overall difference in position (arcsec)
              - difference in V-band magnitude
              - difference in I-band magnitude
           
 
                         star name     RA      Dec       V     I
   ----------------------------------------------------------------------

   cat  star              NSV1754:  73.3296  -3.4512   10.35 12.41 
   TASS star                21125:  73.3299  -3.4509   10.40  9.46    
           pos:  -1.1  -1.0    1.5   dV: -0.05    dI:  2.95
  
   cat  star              NSV1754:  73.3409  -3.3818   11.35 11.02 
   TASS star                21127:  73.3413  -3.3825   11.57 11.23    
           pos:  -1.5   2.7    3.1   dV: -0.22    dI: -0.21
  
   cat  star              NSV1754:  73.4225  -3.4351   11.56 10.99 
   TASS star                21151:  73.4222  -3.4372   12.05 11.06    
           pos:   1.1   7.7    7.7   dV: -0.49    dI: -0.07
  
   cat  star                RU152: 112.4079  -2.1646   11.48 10.94 
   TASS star                25342: 112.4084  -2.1644   11.47 10.99    
           pos:  -1.8  -0.8    2.0   dV:  0.01    dI: -0.05
  
   cat  star                RU152: 112.4182  -2.0704   12.46 11.37 
   TASS star                25343: 112.4192  -2.0668   12.44 11.50    
           pos:  -3.6 -12.8   13.3   dV:  0.02    dI: -0.13
  
   cat  star                RU152: 112.4666  -2.1181   11.60 10.98 
   TASS star                25347: 112.4676  -2.1183   11.56 10.91    
           pos:  -3.4   0.7    3.5   dV:  0.04    dI:  0.07
  
   cat  star                RU152: 112.5038  -2.1636   10.88 10.71 
   TASS star                25351: 112.5037  -2.1646   11.75 10.60    
           pos:   0.5   3.7    3.7   dV: -0.86    dI:  0.11
  
   cat  star                RU152: 112.5093  -2.1360   14.87 14.18 
   TASS star                25352: 112.5093  -2.1341   12.76 11.21    
           pos:   0.0  -6.9    6.9   dV:  2.11    dI:  2.97
  
   cat  star                RU152: 112.5118  -2.1335   13.12 11.71 
   TASS star                25352: 112.5093  -2.1341   12.76 11.21    
           pos:   9.0   2.1    9.3   dV:  0.37    dI:  0.50
  
   cat  star                RU152: 112.5251  -2.0773   11.07 10.16 
   TASS star                25353: 112.5256  -2.0766   11.15 10.22    
           pos:  -1.9  -2.7    3.3   dV: -0.07    dI: -0.06
  
   cat  star                RU152: 112.5435  -2.0194   13.16 12.07 
   TASS star                25355: 112.5410  -2.0207   12.73 11.24    
           pos:   9.0   4.6   10.1   dV:  0.44    dI:  0.83
  
   cat  star             V910_AQL: 305.7236  -1.6516   11.87 11.06 
   TASS star                62089: 305.7243  -1.6519   11.76 11.01    
           pos:  -2.5   1.0    2.7   dV:  0.11    dI:  0.05
  
   cat  star             V910_AQL: 305.7553  -1.6298   13.33 12.65 
   TASS star                62107: 305.7564  -1.6308   12.61 12.04    
           pos:  -4.0   3.5    5.3   dV:  0.72    dI:  0.61
  
   cat  star             V910_AQL: 305.7565  -1.6333   13.27 12.45 
   TASS star                62107: 305.7564  -1.6308   12.61 12.04    
           pos:   0.3  -9.2    9.2   dV:  0.66    dI:  0.41
  
   cat  star             V910_AQL: 305.7816  -1.6307   13.22 12.28 
   TASS star                62134: 305.7831  -1.6300   12.75 11.98    
           pos:  -5.3  -2.7    5.9   dV:  0.47    dI:  0.30
  
   cat  star             V910_AQL: 305.7851  -1.6276   13.82 13.01 
   TASS star                62134: 305.7831  -1.6300   12.75 11.98    
           pos:   7.2   8.7   11.3   dV:  1.07    dI:  1.02
  
   cat  star             V910_AQL: 305.8545  -1.6022   13.02 11.65 
   TASS star                62191: 305.8533  -1.6021   12.99 11.39    
           pos:   4.4  -0.4    4.4   dV:  0.03    dI:  0.26
  
   cat  star             V910_AQL: 305.8809  -1.6551   12.31 11.80 
   TASS star                62216: 305.8806  -1.6549   12.30 12.07    
           pos:   1.2  -0.6    1.3   dV:  0.01    dI: -0.27