147  V2051 OPHIUCHI   (UGSU)   Range: 11.7-15.8V
     Position:   17 08 19.08  -25 48 31.7 (J2000, from .dat file)
     Magnitude:  V=15.791  B-V=-0.345     (Henden, single night

ID     RA (2000)    DEC       X    Y   N    V      ERR     B-V    ERR  
 
a) Comparison star sequence
  
1    17 08 15.0  -25 48 26   -56    6  4  10.978  0.161   0.309  0.185   
2    17 08 22.4  -25 51 50    45 -198  3  11.190  0.051   0.496  0.058   
3    17 08 13.9  -25 48 25   -70    7  3  11.920  0.023   0.758  0.008   
4    17 08 15.7  -25 49 57   -46  -85  3  13.686  0.065   1.920  0.031   
5    17 08 21.7  -25 48 35    35   -3  3  13.794  0.031   1.554  0.017   
6    17 08 11.2  -25 48 19  -107   13  3  14.283  0.031   1.000  0.013   
7    17 08 22.0  -25 48 51    40  -19  3  14.344  0.024   1.528  0.009   
8    17 08 23.9  -25 48 53    65  -21  3  15.154  0.033   0.972  0.011   
9    17 08 20.6  -25 48 48    21  -16  3  15.478  0.020   1.812  0.015   
10   17 08 17.2  -25 47 46   -26   46  3  15.749  0.034   0.815  0.020   
11   17 08 13.7  -25 49 08   -72  -36  3  16.159  0.032   0.865  0.016   
12   17 08 09.6  -25 52 57  -128 -265  3  16.616  0.030   1.170  0.039   
13   17 08 20.6  -25 48 39    21   -7  3  17.228  0.049   1.826  0.041   


b) Wide-colour extension for CCD calibration
 
     17 08 43.1  -25 44 09   324  263  3  12.472  0.029   0.472  0.005   
     17 08 20.3  -25 42 26    16  366  3  16.109  0.043   0.531  0.015   
     17 08 36.7  -25 51 53   238 -201  3  14.354  0.044   2.020  0.009   
     17 08 23.4  -25 46 23    58  129  3  13.950  0.022   2.048  0.048   
     17 08 00.0  -25 47 53  -258   39  3  16.380  0.019   2.091  0.122   

Notes:

1. Stars 1 and 2 are saturated, and their magnitudes and colours are
approximate.

2. There is a VSS RASNZ chart with the following magnitudes. The same
magnitudes are also on the preliminary AAVSO (g) chart for this variable.

                       ID   Henden    RASNZ
                              V         V
                       1    10.978    10.3
                       2    11.190    11.0
                       3    11.921    11.9
                       4    13.686    13.5
                       5    13.794    13.8
                       6    14.283    14.3
                       7    14.344    14.1 

3. This variable has apparently been observed as faint as V=19.60, 
possibly indicating extremely deep eclipses. However more normal 
minima are around V=15.0 to V=15.8. A superoutburst observed in May 
1998, possibly the first superoutburst observed for the variable, 
leads to a probably classification as a SU UMa-type dwarf nova (Kato 
1998, vsnet-chat 1796.


Bruce Sumner
19 August 1999