271  V660 HERCULIS   (UG)    Range: 16p-18.5V
     Position:   17 42 09.17  +23 48 30.1  (J2000, from .dat file)
     Magnitude:  V=18.488  B-V=0.144       (Henden, single night)
                                                            
 ID     RA  (2000)   DEC       X    Y  N    V     ERR      B-V    ERR 

a) Comparison star sequence

1    17 41 53.4  +23 48 19  -218  -11  1  11.352  0.000   0.595  0.000   
2    17 41 50.5  +23 49 40  -257   70  1  12.257  0.001   0.513  0.001   
3    17 42 04.9  +23 48 57   -59   27  1  12.826  0.001   0.689  0.001   
4    17 42 08.9  +23 43 13    -5 -317  1  13.224  0.001   0.731  0.001   
5    17 42 29.4  +23 50 06   276   96  1  13.767  0.001   0.577  0.001   
6    17 42 23.0  +23 43 51   190 -279  1  13.978  0.002   0.919  0.003   
7    17 41 53.8  +23 52 42  -211  252  1  14.265  0.002   1.050  0.004   
8    17 42 10.3  +23 50 20    16  110  1  14.925  0.003   0.767  0.004   
9    17 41 55.6  +23 51 57  -186  207  1  15.176  0.003   0.830  0.005   
10   17 42 23.2  +23 44 29   192 -241  1  15.683  0.005   0.855  0.007   
11   17 42 13.0  +23 51 20    52  170  1  15.880  0.005   0.965  0.009   
12   17 42 07.3  +23 49 46   -26   76  1  16.082  0.006   0.685  0.008   
13   17 42 13.3  +23 47 31    56  -59  1  16.880  0.011   0.748  0.016   
14   17 42 12.7  +23 49 31    48   61  1  17.966  0.028   0.907  0.052   


b) Wide-colour extension for CCD calibration

     17 42 04.8  +23 48 37   -60    7  1  14.967  0.003   0.530  0.004   


Notes:

1. The bright magnitude 6 star at 17h 41m 49.7s +23d 45' 11" is a possible
small amplitude variable, although it was not found to be variable during
the Hipparcos mission. However the Tycho experiment did find suspected
variability, with a median magnitude of V=6.94+/-0.01 and a total range of
0.11 mag. This is  NSV 9547, which GCVS Volume 4 lists as magnitude 6.4p
and of unknown type and range.

2. Another faint variable star, V439 Her, is located at 17h 42m 03.1"  
+23d 47" 07", with a GCVS range of 14.7p-15.6p and of type RRab. During 
the determination of this sequence it was measured at V=16.211.
                                                  

Bruce Sumner
27 March 2002