COMMISSION 27 OF THE I. A. U.
         INFORMATION BULLETIN ON VARIABLE STARS
                      Number 631

                                   Konkoly Observatory
                                   Budapest
                                   1972 February 21


                MINIMA OF ECLIPSING VARIABLES


Some eclipsing variables were observed in order to obtain precise timings of
minima. Except for one case, namely AI Dra, all observations were carried out
with a photoelectric photometer attached to the 12" Clark-refractor of the
University Observatory of Vienna. Measures were made in the yellow spectral
region. I am very indebted to Prof. Hermann Haupt, who made the use of this
instrument possible.

AI Dra however was observed by a photographic method introduced by K.
Schwarzschild in Publ. v. Kuffner'sche Sternwarte, Bd. V. This procedure
makes use of extrafocal star images and is considerably more accurate than the
usual photographic-photometric methods based on focal exposures. The
photographic observations were carried out at Kuffner Observatory.
Panchromatic plates were used.

The times of minima were then determined with the aid of Pogsons curve (S.
Table, the O-C values are according to the elements in SAC 1969).

Star      Min.hel     m.e       O-C    Type of   n
          2440000+  +-.0001d            min.

SV Cam   528,3615     4       +0,0025    P       81
VW Cep   511,3453     9                  S       31
VW Cep   512,3255    10       -0,0114    P       68
VW Cep   544,3294    10       -0,0140    P       49
VW Cep   547,2478     7                  S       69
AI Dra   082,4064     8       +0,0095    P       25
SW Lac   542,3457     4                  S       58

Matematisches Institut der Universitat


HERBERT MUTHSAM
Strudlhofgasse 4
A-1090 Wien