COMMISSION 27 OF THE I. A. U.
        INFORMATION BULLETIN ON VARIABLE STARS
                     NUMBER 501

                                Konkoly Observatory
                                Budapest
                                1970 December 28

           MINIMA OF ECLIPSING VARIABLES

      A photoelectric study of the eclipsing binaries
U Cep and RZ Cas was carried out in yellow light with the
8-inch refractor or the Kourovka observatory at the Urals
University. The comparison stars were HD 6006, m_v = 7.89m,
Sp A0 for U Cep and BD 69d171, m_v = 8.0m, Sp A0 for RZ Cas.
Two newly observed primary minima are given.



-----------------------------------------------------------------
Star     JD hel        E                O-C          n  method
         2400000+                                       of obs.
-----------------------------------------------------------------
U Cep    36466.6013   11463            +0.1872d^1         pg
         541.3858     11493            +0.1847            pg
         576.2872     11507            +0.1855            pg
         581.2729     11509            +0.1854            pg
         825.5791     11607            +0.1873            pg
         40273.4695   12990            +0.3959       35   pe
         779.551      13193            +0.419        15   vis
         789.529      13197            +0.426        11   vis
RZ Cas   36816.4975   16282            -0.017^2           pg
         37912.5334   17199            -0.0274            pg
         38676.2915   17838            -0.0352            pg
         40274.3375   19175            -0.0410       14   pe
         789.490      19606            -0.042        15   vis
AQ Peg   37882.491    2367             +0.079^3           pg
         40096.335    2766             +0.108        18   vis
UX UMa   40777.4117   68318            -0.0057^4     16   vis
         779.3779     68328            -0.0062        9   ivs
--------------------------------------------------------------

n: total number of estimates of brightness;
1. C = Min.hel. JD = 2407890.2957+ 2.4929005d E;
2. C = Min.hel. JD = 2417355.4233+ 1.1952519 E;
3. C = Min.hel. JD = 2424749.3305+ 5.548408 E;
4. C = Min.hel. JD = 2427341.2221+ 0.196671379 E;



      Photographic moments of minima obtained with sky
patrol plates at the Odessa observatory are also presented.
      Finally visual observations were made with the
19-inch reflector on UX UMa, AQ Peg, and with a binocular on
U Cep and RZ Cas for the determination of minima and for
studying their period-variations.

                         L.P. SURKOVA

                     The Pedagogical Institute
                           Gorky