157  AY LACERTAE   (M/UG?)   Range: 14.5-<20p 
     Position:   22 22 23  +50 23 29    (GCVS)
     Magnitude: 

ID     RA (2000)    DEC       X    Y   N    V      ERR      B-V    ERR
 
a) Comparison star sequence
    
1    22 22 20.5  +50 24 36   -23   66  1  10.539  0.000   0.744  0.001   
2    22 21 55.8  +50 27 32  -259  242  1  11.079  0.001   0.125  0.001   
3    22 22 39.9  +50 21 00   161 -150  1  11.577  0.001   0.776  0.001   
4    22 22 31.4  +50 24 37    80   67  1  12.164  0.001   0.356  0.001   
5    22 22 16.6  +50 23 47   -62   17  1  12.950  0.001   0.470  0.001   
6    22 22 09.2  +50 19 22  -132 -248  1  13.520  0.002   0.432  0.003   
7    22 22 30.6  +50 24 28    72   58  1  13.948  0.002   0.756  0.004   
8    22 22 36.1  +50 20 17   126 -193  1  14.316  0.003   0.542  0.004   
9    22 22 26.8  +50 23 25    36   -5  3  14.722  0.005   0.723  0.004   
10   22 22 26.6  +50 23 54    34   24  3  15.005  0.006   0.982  0.004   
11   22 22 23.6  +50 23 26     5   -4  3  15.566  0.006   0.685  0.006   
12   22 22 23.8  +50 22 42     8  -48  3  16.273  0.011   0.652  0.016   
13   22 22 26.5  +50 23 41    34   11  2  16.590  0.000   0.873  0.009   
14   22 22 24.8  +50 23 30    17    0  2  17.345  0.008   0.846  0.006   
15   22 22 24.6  +50 23 44    15   14  2  17.863  0.008   1.049  0.011   
16   22 22 18.1  +50 23 08   -47  -22  2  18.352  0.011   0.975  0.018   
17   22 22 22.7  +50 23 54    -3   24  2  18.811  0.022   0.972  0.018   
18   22 22 22.2  +50 23 23    -8   -7  2  19.070  0.027   0.900  0.013   


b) Wide-colour extension for CCD calibration
 
     22 22 45.3  +50 24 01   213   31  1  12.317  0.001   0.292  0.001   
     22 22 24.5  +50 21 34    14 -116  1  12.333  0.001   1.453  0.002   
     22 22 46.1  +50 24 21   220   51  1  12.102  0.001   1.660  0.002   
     22 22 39.1  +50 20 30   155 -180  1  13.488  0.002   1.781  0.004   


Notes:

1. The first five bright stars in this sequence, all brighter than
magnitude 13, are saturated and their magnitudes are only approximate. 
They should be used for guidance only until their magnitudes are 
correctly determined. Star 1 has reliable Tycho-2 photometry: V=10.13 
+/-0.03.

2. This possible UG has been reclassified as a possible faint Mira variable 
in GCVS IV. However examination of five Schmidt plate images taken between 
1952 and 1990 show no varying object in this field. It could still be a 
UG variable.

3. The DWS catalog of 1997 locates this variable about 25 arcsec north of
the position given in GCVS IV. In fact the DWS position is very close to
that of star 18 in this sequence, but star 18, at magnitude 18.8V, appears
to be an ordinary field star. The exact position of AY Lac is thus
currently unknown.


Bruce Sumner
Posted 020119