COMMISSION 27 OF THE I. A. U.
                INFORMATION BULLETIN ON VARIABLE STARS
                            NUMBER 786

                                           Konkoly Observatory
                                           Budapest
                                           1973 April 30


            PHOTOGRAPHIC OBSERVATIONS OF ECLIPSING VARIABLES



--------------------------------------------------
Var.        Min.helioc.  n         O-C_M     O-C_K
            J.D. 244...               
--------------------------------------------------
RT And 1    1605.412     8       -0.007d   -0.006d
            1717.372     9       +0.003    +0.004
WY Cnc      1765.4225   10       -0.0018   -0.0082
AB Cas      1570.390    10       +0.007    +0.022
ZZ Cyg      1596.396     9       -0.031    -0.016
            1601.425     8       -0.031    -0.016
BR Cyg      1595.415    13       -0.008    -0.008
TY Del      1594.407    10       -0.007    +0.008
UV Leo      1766.401    11        0.000    +0.012
            1772.403    11       +0.001    +0.013
ET Ori      1741.398    16       +0.001    +0.001
RT Per      1597.402    12       -0.051    -0.030
X Tri       1593.371    13       -0.025    -0.022
AW Vul      1602.4035    9       -0.0145   -0.0117
BE Vul      1573.406    10       +0.010    +0.001
--------------------------------------------------



        1 Last plate (.453) disturbed by clouds. C_M, from GCVS 1969/70,
        C_K from SAC 44 (1973). n= number of plates. Each plate has been
        observed in four positions, each turned 90deg.


        RR Lyr-star Max.helioc. n   O-C_M   O-C_K
        -----------------------------------------
        S Com       1395.504   13 -0.025d -0.014d


New elements and 3 earlier maxima give the following epochs and
O-C:  Max.= J.D. 2438851.480 + 0.5865852d E;
  Obs.max.         38851.432   n= 8   Ep.=    0 O-C= +0.002d
                   39918.477     14        1819      -0.001
                   41063.488     10        3771      -0.005
                   41395.504     13        4337      +0.004




                                      P. AHNERT
                                      Sonneberg




       INSTANTANEOUS ELEMENTS OF 4 ECLIPSING STARS


                AB CASSIOPEIAE

(I) Min.= J.D.2425404.419+ 1.366851d E ; sigma=+-0.006d
T   = J.D.2425404 to 2426693;    n=12
(II) Min.= J.D.2432673.391+ 1.3668729d E ; sigma=+-0.0037d
T   = J.D.2432673 to 2436540;    n=44
(III) Min.= J.D.2436868.325+ 1.3668813d E ; sigma=+-0.0038d
T   = J.D.2436868 to 2441570 ;   n=72
(Mean min.=J.D.2425404.388 + 1.3668708d E ; sigma=+-0.015d;


                   ZZ CYGNI

(I) Min.= J.D.2417442.419+ 0.6286185d E ; sigma=+-0.0033d
T   = J.D.2417442 to 2425763;    n=42
(II) Min.= J.D.2427955.422+ 0.6286167d E ; sigma=+-0.0026d
T   = J.D.2427955 to 2435240;    n=25
(III) Min.= J.D.2438920 to 2441601;   sigma=+-0.0021d
T   = J.D.2438920 to 2441601;    n=22
(Mean min.=J.D.2415020.372+ 0.6286167d;  sigma=+-0.0065d)


                 AB VULPECULAE

(I) Min. = J.D.2426319.342+ 0.8064522d E ; sigma=+-0.0029d
T   = J.D.2426319 to 2437940 ;   n=26
(II) Min.= J.D.2439376.596+ 0.8064498d E ; sigma=+-0.0030d
T   = J.D.2439376 to 2441602;    n=6
(Mean min.=J.D.2426319.342+ 0.8064512d E ; sigma=+-0.0064d)


                BO VULPECULAE

(I) Min.= J.D.  2432379.773 + 1.945910d E  ;  sigma=+-0.0069d
T   = J.D.2432379 to 2435742;     n=17
(II)Min.= J.D.2435989.431+ 1.945866d E ; sigma=+-0.0019d
T   = J.D.2435989 to 2441276;    n=15



Mean elements of BO Vul are unfit. The large scattering of the
minima computed by (I) is caused by the method of Ashbrook (n=12),
who has set single photographic observations into the mean 
lightcurve of Nassau.
Sigma is the scattering (m.e.) of the observed minima, T is the time-
interval, for which the instantaneous elements are valid and n
is the number of minima used for the calculation. Mean elements
have been given in parentheses.



                              P. AHNERT          
                              Sonneberg