168  V1316 CYGNI   (UGSU:)   Range: 14.1-17.6V
     Position:   20 12 13.67  +42 45 51.4  (J2000, in .dat file)
     Magnitude:  V=17.583    B-V=0.252    (in .dat file) 
         
a) Comparison star sequence
                                                            
ID      RA  (2000)   DEC       X    Y  N    V      ERR    B-V    ERR

1    20 11 56.3  +42 42 48  -192 -183  3  12.387  0.017   0.496  0.028   
2    20 11 45.1  +42 51 06  -315  315  3  12.796  0.017   0.512  0.005   
3    20 12 27.1  +42 43 09   148 -163  3  13.057  0.016   0.637  0.005   
4    20 12 36.2  +42 48 32   247  161  3  13.251  0.014   0.816  0.003   
5    20 12 06.8  +42 48 50   -76  179  3  13.840  0.016   0.706  0.004   
6    20 12 10.3  +42 45 59   -38    8  3  14.108  0.013   0.850  0.005   
7    20 12 08.3  +42 48 04   -60  133  3  14.314  0.013   0.974  0.014   
8    20 12 12.7  +42 45 54   -11    2  3  14.779  0.014   0.865  0.006   
9    20 12 18.7  +42 44 23    55  -88  3  15.120  0.016   0.944  0.027   
10   20 12 13.2  +42 43 38    -6 -133  3  15.683  0.011   0.883  0.009   
11   20 12 13.9  +42 47 56     3  125  3  16.085  0.018   0.979  0.017   
12   20 12 12.6  +42 44 45   -12  -67  3  16.394  0.013   0.999  0.062   
13   20 12 11.9  +42 46 32   -20   41  3  16.970  0.063   1.346  0.060   
14   20 12 15.9  +42 45 20    24  -31  3  17.738  0.307   1.239  0.398   
15   20 12 20.6  +42 47 08    76   77  2  18.261  0.000   0.982  0.152   


b) Wide-colour extension for CCD calibration

     20 12 35.6  +42 51 04   241  313  3  13.713  0.014   0.581  0.004   
     20 11 57.0  +42 41 38  -184 -253  3  13.866  0.019   0.626  0.005   
     20 12 27.0  +42 44 49   147  -62  3  11.521  0.171   1.786  0.169   
     20 12 01.7  +42 47 17  -132   86  3  12.131  0.054   2.051  0.057   
     20 11 47.5  +42 44 18  -289  -93  3  15.732  0.006   2.421  0.061   


Notes:

1. The position of V1316 Cygni shown in Downes and Shara, PASP, 1993 
is incorrect. The real variable is in fact the faint star some 12 
arcsec east of the indicated star. This has been determined from 
B and V photometry (the candidate is very blue) and magnitude
fluctuations in quiescence, using photometric data obtained by Henden 
and Honeycutt for their paper Secondary Photometric Standards for 
Northern Cataclysmic Variables and Related Objects, PASP,109,441,1997.

2. The D&S candidate is star 8 in this sequence, and extreme care will be 
necessary not to confuse this constant star with the variable, particularly 
when the variable is faint.


Bruce Sumner
5 September 2000