COMMISSION 27 OF THE I. A. U.
          INFORMATION BULLETIN ON VARIABLE STARS
                       NUMBER 892

                                  Konkoly Ohservatory
                                  Budapest
                                  1974 May 27


     UBV OBSERVATIONS OF 31 CYGNI DURING THE 1972 ECLIPSE




   On eight nights between May and July, 1972, photoelectric 
observations of 31 Cygni were made at the Fernbank Science Center 
Observatory using the 91 cm reflector. An unrefrigerated EMI 6256 
photomultiplier tube was used with standard UBV filters. All observations 
of 31 Cygni were made differentially with respect to 26 Cygni, 
and have been transformed to the standard UBV system. Each table 
entry is an average of four separate observations.

JD (Hel) DeltaV   DeltaB    DeltaU       JD (Hel)  DeltaV   DeltaB   DeltaU
2441000+                                  2441000+
442.7128 -1.208   -0.799    -0.187        501.7581 -1.253   -1.020   -1.109
   .7495 -1.212   -0.785    -0.148        502.6217 -1.266   -1.090   -1.379
   .7879 -1.212   -0.766    -0.118           .6431 -1.267   -1.084   -1.376
   .8065 -1.207   -0.760    -0.114           .6638 -1.257   -1.079   -1.394
442.8279 -1.197   -o.744    -o.102        502.6753 -1.243   -1.065   -1.404
490.6643 -1.184   -0.729    -0.045        504.6261 -1.243   -1.042   -1.554
   .7446 -1.195   -0.738    -0.049           .6477 -1.230   -1.068   -1.554
   .7933 -1.184   -0.747    -0.052        504.6587 -1.225   -1.055   -1.546
490.8143 -1.185   -0.751    -0.067        510.7091 -1.257   -1.145   -1.743
491.6071 -1.167   -0.735    -0.071           .7381 -1.255   -1.138   -1.758
   .6463 -1.195   -0.748    -0.075           .7657 -1.259   -1.146   -1.771
   .6878 -1.190   -0.767    -0.073        510.8049 -1.261   -1.154   -1.775
   .7491 -1.199   -0.747    -0.058        519.7415 -1.257   -1.131   -1.785
491.7785 -1.180   -0.728    -0.039           .7688 -1.243   -1.116   -1.758
501.6569 -1.269   -1.041    -1.052           .7953 -1.243   -1.116   -1.752
   .6820 -1.261   -1.013    -1.058        519.8163 -1.239   -1.102   -1.760
   .7214 -1.253   -1.015    -1.091

It is noted that during the total phase of the eclipse (JD 2441490 and
491) and also outside of eclipse, variations as large as 0.03 were
found in the ultraviolet. This variation is significantly greater than
observational scatter would indicate, and has been previously reported
by others (Lovell and Hall, PASP 85, 131, 1973; Bloomer and Wood,
PASP 85, 348, 1973).





                           RICHARD M. WILLIAMON
                           Fernbank Observatory
                           Atlanta, Georgia 30307
                           U.S.A.