COMMISSION 27 OF THE I.A.U.
              INFORMATION BULLETIN ON VARIABLE STARS
                           Number 1413

                                                     Konkoly Observatory
                                                     Budapest
                                                     1978 April 19


          PHOTOELECTRIC MINIMA AND LIGHT CURVES
        OF THE ECLIPSING VARIABLE DO CASSIOPEIAE

The variability of DO Cas (BD +59d529, HD 16506) was discovered 
by Hoffmeister (1947). Photoelectric light curves were
obtained by Schneller and Daene (1952), Winkler (1966) and Gleim
and Winkler (1969), Cester (1977). Mannino (1958) obtained 
spectroscopic elements. The photographic magnitude of the star varies
from 8m.60 to 9m.25. DO Cas was classified as a typical Beta Lyr type
eclipsing variable by Hoffmeister (1947). The light elements were
obtained by him as follow:

    Hel Min J.D. 2428 865.450 + 0d.684655*E.

   Photoelectric observations of DO Cas in B,V colours were
made with the 48 cm Cassegrain telescope at the Ege University
Observatory on 5 nights between September 1977 and January 1978.
The photometer was furnished with a 1P21 photomultiplier tube
and standard Johnson B,V filters. In the observations BD +59d548
was used as comparison star. 5 primary minima were obtained and
are given in the following Table.


                       Times of Minima

  Hel Min       Min   (O-C)_I   (O-C)_II  (O-C)_III   n   Fil

  2443408.3972   I    -0.0041   +0.0011    -0.0009    32   b
      425.5748   I    -0.0032   +0.0021       0       24   v
         .5155   I    -0.0025   +0.0028    +0.0007    24   b
      501.5126   I    -0.0035   +0.0020    -0.0001    62   B, V
      502.1960   I    -0.0047   +0.0008    -0.0014    26   V
         .1967   I    -0.0040   +0.0015    -0.0007    26   B
      512.4677   I    -0.0030   +0.0024    +0.0003    47   B, V

   (O-C)_I values GCVS 1974., (O-C)_II values SAC 1977., (O-C)_III values
were obtained with the elements of Cester (1977).

    Hel Min J.D. 2433 926.4573 + 0d.6846661*E.

   The light curve is shown in the Figure where the individual
magnitude differences between the variable and the comparison
star BD +59d548 have been plotted against the phases which were
calculated with the elements given by Cester.

                        [FIGURE 1]


                                    OKAN TUMER

                              Ege University Observatory
                              P.K. 21 Bornova-Izmir, Turkey



References:

1. Cester, B., Ciuricin, G., Mardirossian, F. and Pucillo 1977, Astron.
     Astrophys. Suppl. 30, 223 [BIBCODE 1977A&AS...30..223C ]
2. Chambliss, C.R. 1970, Astron. J. 75, 731 [BIBCODE 1970AJ.....75..731C ]
3. Glein, J.K. and Winkler, L. 1969, Astron. J. 74, 1191 [BIBCODE 1969AJ.....74.1191G ]
4. Kwee, K.K. and Woerden, H. van 1956, Bull. Astron. Inst. Neth. 12, 327 [BIBCODE 1956BAN....12..327K ]
5. Mannino, G., 1958, Mem. Soc. Astron. Ital. 29, 433 [BIBCODE 1958MmSAI..29..433M ]
6. Schneller, H. and Daene, H. von, 1952, Astron. Nachr. 281, 25 [BIBCODE 1952AN....281...25S ]
7. Winkler, L., 1966, Astron. J. 71, 40 [BIBCODE 1966AJ.....71...40W ]