COMMISSION 27 OF THE I. A. U.
           INFORMATION BULLETIN ON VARIABLE STARS
                      Number 2784

                                        Konkoly Observatory
                                        Budapest
                                        30 August 1985

                                        HU ISSN 0374 - 0676


                    MINIMUM TIMING OF RZ Cas


 Primary minimum of the eclipsing binary RZ Cas was observed through HalphaN
and HalphaW filters, during 3 nights 17, 23, and 29 December 1984, using the 20"
cassegrain telescope of Biruni Observatory and an RCA4509 phototube.

 The variable star was observed against BD+67deg 215, and BD+69deg 171 was used as the
check star. Differential observations were corrected for extinction, and the
HalphaW light curve is shown in the Figure. Phases were calculated 
according to the ephemeris (Parenago, 1952):

        HJD 2417355.4233 + 1.1952519d E

  Time of minimum was found to be 2446028.2601 by fitting a parabola to the
observations within 0.05 phase of the primary minimum. An O-C of -0.0610 days
was added to the calculated JDs to bring the primary minimum to the zero phase.
This O-C together with the minimum given by Parenago suggest a period of
1.1952494 days.
  As reported by other observers, an approximately flat bottom with a
duration of about 15 minutes exists.

  Results for HalphaN are not offered, because of large scattering of data, and
low precision of results.





                       N. RIAZI, S. NASIRI, and M.R. AHMADY
                       Biruni Observatory
                       Physics Department
                       Shiraz University
                       Shiraz, Iran





 Reference:
 Parenago, P.P., 1952, Variable Stars 9, 125.



                               [FIGURE 1]