COMMISSION 27 OF THE I. A. U.
        INFORMATION BULLETIN ON VARIABLE STARS
                    Number 2137

                                 Konkoly Observatory
                                 Budapest
                                 1982 May 4

                                 HU ISSN 0374-0676


       PHOTOELECTRIC MINIMA OF BW DRACONIS



  The short period variable BW Dra (SAO 166035) was
observed during 1980 and 1981. The observations were made
using a two-beam, multi-mode, nebular-stellar photometer
attached to the 48-inch Cassegrain reflector at Kryonerion
Astronomical Station of the National Observatory of Athens.
   The B and V filters used are in close accordance to the
standard ones and reduction of the observations has been
made in the usual way (Hardie, 1962).
   From our observations seven primary and five secondary
minima have been derived, From Yamasaki's (1979) and our
epochs the following ephemeris formula was found :

   Min I( Hel. J,D.)= 2443187.23973 + 0.292279163d.E     (1)
                          +- 0.0004  +-0.00000010



   In the following Table our minima times are represented.
The successive columns of the Table give. the heliocentric
J,D., the residuals (O-C)_I , (O-C)_II, ( O-C)_III and the type
of minimum.
   The times of minima have been calculated by Kwee and Van
Worden's method (1956) and are the mean values from B and V
observations. The ephemeris formulae used are those of
Kukarkin et al. (1969), Yamasaki (1979) and our as is given
by the foregoing equation (1),

                       Table I
Hel. J.D.     (O-C)_I  (O-C)_II    (O-C)_III   Min
2440000.+      days      days        days     Type

4728.4258    +0.0802    -0.0041    -0.0020     p
4732.3734    +0.0817    -0.0007    -0.0002     s
4732.5195    +0.0817    -0.0007    -0.0002     p
4754.4417    +0.0795    -0.0090    -0.0011     p
4754.5859    +0.0796    +0.0071    -0.0008     s
4755.3187    +0.0817    +0.0095    +0.0013     p
4755.4650    +0.0819    +0.0097    +0.0014     s
4756.3415    +0.0815    +0.0097    +0.0011     s  
4756.4876    +0.0814    +0.0098    +0.0010     p
4759.4094    +0.0801    +0.0099    +0.0001     p
4760.4319    +0.0797    +0.0098    -0.0004     s
4791.4551    +0.0798    +0.0104    -0.0002     p




References:

Hardie, R. H.: 1962, Stars and Stellar Systems, Vol. II,
                  Astronomical Techniques, ed. Hiltner, W.A., The
                  University of Chicago Press, Chicago. pp. 178-208
Kukarkin, B. J. et al.: 1969, General Catalogue of Variable Stars,
                  Moscow. [BIBCODE 1969gcvs.book.....K ]
Kwee, K, K. and   Van Woerden,  H.: 1956, Bull. Astron.  Inst, Neth, 92,
                  327. [BIBCODE 1956BAN....12..327K ]
Yamasaki, A.: 1979, Astrophys. Space Sci. 60, 173, [BIBCODE 1979Ap&SS..60..173Y ]


P. ROVITHIS                      H. ROVITHIS - LIVANIOU
National Observatory of          Astronomy Dept., Athens University
Athens, Athens 306               Panepistimiopolis, Athens 621
GREECE                           GREECE