COMMISSION 27 OF THE I. A. U.
        INFORMATION BULLETIN ON VARIABLE STARS
                    Number 1660

                                   Konkoly Observatory
                                   Budapest
                                   1979 August 10




      PHOTOELECTRIC PHOTOMETRY OF THE VARIABLE ST Com




Photoelectric observations of ST Com, an RR Lyrae type star, were
performed at Abastumani Astrophysical Observatory over 10 nights
from April 30, 1976 till May 22, 1977 with the AZT-14A telescope
(diameter 48 cm). About 170 light measurements in each region of
the UBV system have been obtained: The r.m.s. errors of observations 
are sigma_U=+-0.019m,sigma_B=+-0.013m, sigma_V=+-0.010.
V, B-V and U-B curves are shown in the Figure. The Table lists
the extreme values of the light and colour curves.

                      [FIGURE 1]


Magnitude   Maximum   Minimum   Amplitude
U           11.30     12.31     1.01
B           11.17     12.28     1.11
V           10.96     11.82     0.86
U-B         +0.13     +0.03     0.10
B-V         +0.21     +0.46     0.25


Asymmetry of the B light curve equals to 0.21p. The elements
Max_hel=2427862.585+ 0.5989795*E yield an O-C value of -0.022 day.




                          I. PH. ALANIA
                          O.P. ABULADZE
                      Abastumani Astrophysical
                      Observatory, Georgia, U.S.S.R.