COMMISSION 27 OF THE I. A. U.
          INFORMATION BULLETIN ON VARIABLE STARS
                      Number 2597

                                           Konkoly Observatory
                                           Budapest
                                           1 October 1984

                                           HU ISSN 0374-0676

      TIMES OF MAXIMUM LIGHT OF THE BETA CMa STAR BW VULPECULAE

  An extensive study of the times of maximum light of BW Vul was carried
out by Valtier (1976). In it he considers all the available photometric and
spectroscopic data in view of the importance of establishing rates of period
increase for comparison with theoretical models of the stars. Valtier finds
that, in agreement with Cherewick and Young (1975), all the observations
can be fitted by a unique ephemeris if one considers that the period is
linearly increasing with a rate of 1.8 s/century.
  In view of the importance of this result, some additional observations
were carried out at the Observatorio Jose Arbol y Bonilla, Zacatecas, Mexico,
with the 50 cm. telescope in the UBV system with a 1P21 uncooled phototube.
The comparison stars were HD 199102 and HD 198527, except in 1982 when
HD 198820 and HD 198527 were utilized.
  Table I lists the new times of maximum light for BW Vulpeculae. The
photometric data and the analysis of periodicity will be published elsewhere.

Table I Times of maximum light of BW Vulpeculae
H.J.D.                   H.J.D.                     H.J.D.
44117.7225               44153.7070                 44475.7782
44142.6620               44155.7220                 44500.7160
44143.6560               44157.7378                 44505.7409
44144.6560               44159.7490                 45230.6945
44146.6773               44163.5651                 45231.6977
44149.6950

Acknowledgement. Two of us (MRH and MRB) would like to thank Dr. T.
Jarzebowski for suggesting the observations of this star.


                      M. RIOS HERRERA (1), M. RIOS BERUMEN (1),
                         J.H. PENA (2) and R. PENICHE (2)
                             
                      1 Universidad Autonoma de Zacatecas,
                        Apdo. Postal 275, Zacatecas, Zac., Mexico

                      2 Instituto de Astronomia
                        Universidad Nacional Autonoma de Mexico
                        Apdo. Postal 70-624, 04510 Mexico, D.F. Mexico

References:

Cherewick, T.A., and Young, A., 1975, Publ. Astron. Soc. Pacific, 87, 311. [BIBCODE 1975PASP...87..311C ]
Valtier, J.C., 1976, Astron. Astrophys., 51, 465. [BIBCODE 1976A&A....51..465V ]