COMMISSION 27 OF THE I.A.U.
              INFORMATION BULLETIN ON VARIABLE STARS
                           Number 1259

                                                    Konkoly Observatory
                                                    Budapest
                                                    1977 April 5


         PHOTOELECTRIC OBSERVATIONS OF DELTA CETI

Delta Ceti, a beta CMa variable, was observed photoelectrically 
in colours (B) and (V) for a total of seven nights at Ege 
University Observatory in December 1974, January 1975 and November
1976. The observations made in December 1974, January 1975  and
their results were published by Tunca (1975).
   The observations were carried out with the 48 cm Cassegrain
telescope with an unrefrigerated 1P21 photomultiplier. The 
properties of the filters used are given in Table 1.

                   Table 1

Colour   Wavelength   Max. Per.   HW    Thickness
              (A)        (%)      (A)     (mm)

B            4350        64       920      8
V            5550        53       860      7

   BD -0d378 was again used as the comparison star.
   In this work all observations made in November 1976 and
the previous ones, Tunca (1975), were again plotted and max.
times calculated for each light curve.
   The necessary reduction and corrections were made in all
observed values. Moreover the systematic errors made in previous
observational results were also removed.
   The calculated average amplitudes and the (UBV) magnitudes
measured on December 11, 1974 were found to be the same as those
given by Tunca (1975) and are as follows:

         A(B) = 0.034m    m(B) = 3.939m
                 +- 2     m(V) = 9.144m
         A(V) = 0.032     (B-V)=-0.205m
                 +- 2

   Jerzykiewicz (1970) has given the light element for this
star as:

   Max. Blue Light JD Hel.=2438385.6860+0.16113800.E:
                                    +-8       +-25

   The calculated max. times due to Jerzykiewicz (1970), our
observed max. times and the (O-C)_max.t. values in colour (B)
are given in Table 2.

                        Table 2

Obs.max.times          Calc.max.times      (O-C)_max.t.

2442393.3472            2442393.3492        +  0.0021d
    419.2921                419.2924        -   .0003
    428.3146                428.3161        -   .0015
    430.2497                430.2498        -   .0001
    431.2182                431.2166        +   .0016
2443101.3885            2443101.3897        -   .0012
    113.3121                113.3139        -   .0018

   We found no regular variation in the (O-C) values, because
there were no sufficient observations available. However, it can
be seen that the (O-C) values scatter irregularly about calculated 
max. times given by Jerzykiewicz (1970) with an approximate
amplitude of 0.0025 day.


                                  ZEYNEL TUNCA

                            Ege University Observatory
                                  Izmir, Turkey



References:

Jerzykiewicz, M. 1970, Lowell Obs. Bull. No 155, 7, 198
Tunca, Z. 1975, I.B.V.S. No. 1103