[vsnet-sequence 26] V446 Her sequence

["Bruce Sumner" <b.sumner@bom.gov.au>]

The current VSNET campaign on V446 Her might benefit from an
accurate comparison star sequence. Such a sequence follows. 
Visual observers only need use the stars listed in Part a.
Regards,
Bruce Sumner
---------------
156  V446 HERCULIS   (NA)   Range: 2.8-18.8p
     Position:   18 57 21.61  +13 14 28.9 (J2000, from .dat file)
     Magnitude:  V=16.121  B-V=0.472      (from .dat file)

ID     RA  (2000)   DEC       X    Y   N    V      ERR     B-V    ERR 

a) Comparison star sequence
 
1   18 57 31.2  +13 16 46   139  137  7  12.518  0.054   1.282  0.075 
2   18 57 23.6  +13 13 16    30  -73  7  12.586  0.045   0.614  0.053 
3   18 57 09.4  +13 16 11  -178  102  7  13.236  0.016   0.891  0.013 
4   18 57 02.7  +13 12 11  -276 -138  7  13.419  0.014   1.213  0.015 
5   18 57 40.2  +13 17 11   271  162  7  13.777  0.019   0.526  0.012 
6   18 57 22.8  +13 14 17    18  -13  7  14.048  0.019   0.941  0.018 
7   18 57 15.7  +13 15 11   -86   42  7  14.459  0.011   0.872  0.017 
8   18 57 26.4  +13 14 53    70   24  7  15.173  0.022   0.878  0.011 
9   18 57 20.9  +13 14 13   -10  -16  7  15.693  0.015   2.132  0.058 
10  18 57 20.4  +13 13 55   -18  -34  7  16.103  0.019   1.674  0.029 
11  18 57 17.3  +13 13 46   -63  -43  7  16.506  0.032   1.868  0.080 
12  18 57 27.1  +13 14 17    81  -12  7  17.414  0.043   1.270  0.036 
13  18 57 20.2  +13 14 20   -20   -9  7  18.028  0.073   1.459  0.379 
  

b) Wide-colour extension for CCD calibration

    18 57 37.9  +13 09 38   238 -291  5  12.947  0.016   0.492  0.014 
    18 57 25.1  +13 08 56    51 -333  4  14.329  0.017   0.499  0.010 
    18 57 44.6  +13 10 55   336 -214  2  12.511  0.058   0.519  0.058 
    18 57 15.2  +13 16 13   -93  104  7  14.263  0.013   2.272  0.021 
    18 57 38.7  +13 17 13   249  164  7  14.511  0.027   2.295  0.023 
    18 57 31.8  +13 13 02   150  -87  7  13.319  0.011   2.333  0.015 


Notes:

1. Stars 1 and 2 are saturated, and their magnitudes should be used 
for guidance only.

2. There is a photoelectric sequence of some of the brighter stars in 
this field in a paper by Stienon, PASP,75,45S,1963. The stars common 
to the two sequences are:

                           Henden         Stienon
                    Star   V     B-V      V     B-V
                      1  12.518  1.282   12.49  1.46
                      2  12.586  0.614   12.65  0.61
                      3  13.236  0.891   13.31  0.91
                      4  13.419  1.213   13.46  1.39

3. The bright star HD 175959 is located only 1.7 arcmin north of the
variable. It was measured by Stienon as follows: V=8.90 B-V=1.55.

4. This field is predominantly populated with red stars, and it is
impossible to create a sequence composed of stars of similar colour.
Observers should be aware that the bright half of this sequence are 
mostly blue stars, whereas the fainter half of the sequence are 
mostly red stars.

5. V446 Her is the NE optical member of a very tight quadruple 
cluster of 18 and 19 magnitude stars, all located inside a circle of 
5 arcsec diameter. Magnitudes of the individual components will be 
reported later.

Bruce Sumner
6 September 2000

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