COMMISSION 27 OF THE I. A. U.
      INFORMATION BULLETIN ON VARIABLE STARS
                   NUMBER 147



                                       Konkoly Observatory
                                       Budapest
                                       25 July 1966



               THE ECLIPSE OF AZ CAS



        Photoelectric observations of the present year eclipse of the
long period eclipsing binary AZ Cas (P~ 3400 days; mpg = 9. 9) are
carried out with the 40 cm refractor of the Teramo Observatory. 
Unfavorable weather conditions together with the occurrence of night
lower culmination of the star prevented the observation of the beginning 
of the eclipse which has been entered between April 14 and
May 18, 1966: according to Ashbrook (ApJ Suppl. 15) the beginning of
the partial phase was expected to occur April 24, whereas Richter
(MVS 331) foresaw the phenomenon for March 24.

        At present the star is 0.30m weaker (V magnitudes) than at
the maximum of light and appears to be very red (provisional value
of B - V: +2.20m). The end of the eclipse is to be expected to occur
next August. Accurate photometric and spectographic observations of
the partial phase, whose length would range from 5 to 10 days, should
be of fundamental importance for the derivation of the light elements
and for the study of the phenomena related to the filtering of the light
of the blue component through the outer envelopes of the red giant.


  Teramo Observatory
  July 20, 1966.

                                      P. TEMPESTI