COMMISSIONS 27 AND 42 OF THE IAU
             INFORMATION BULLETIN ON VARIABLE STARS
                         Number 3929

                                               Konkoly Observatory
                                               Budapest
                                               20 August 1993

                                               HU ISSN 0374 - 0676


            A NEW W UMa VARIABLE IN THE FIELD OF AN Gru^1


  In the course of a CCD photometric investigation on AN Gru, a Cataclysmic Variable
candidate (Steiner, Cieslinski and Jablonski 1988) we discovered a new W UMa variable
among the comparison stars. The object, labeled V in Fig. 1, has approximate coordinates
alpha =23h05m04s, delta = -47d43.1' (epoch=1950.0). Offsets with respect 
to AN Gru are 6" to the West and 111" to the South.
  The differential V magnitudes for several stars in the field of AN Gru were obtained
from 1989 to 1993 with a Wright Instruments camera using a P8603 GEC chip (385 x 578
pixels, 0.58"/ pixel) at the 0.6 m telescope of CNPq/Laboratorio Nacional de Astrofisica
Brazil. The data were reduced using the aperture photometry tasks of the APPHOT
package of IRAF^2. In some selected nights we calibrated the system with the aid of the
photometric sequences of Graham (1982). This gives V=13.32+-0.02 for the star labeled
C 1 in Fig. 1.
  The period of the new eclipsing binary was obtained by means of standard power
spectrum analysis followed by CLEAN deconvolution of the effects of an irregular sampling
window. Fig. 2 shows 254 V measurements folded on the orbital period. 

                            [FIGURE 1]

     Figure 1:   Finding chart for the new eclipsing binary.


 1 Based on observations made at CNPq/LNA, Brazil
 2 IRAF is distributed by National Optical Astronomy Observatories, which is
   operated by the Association of Universities for Research in Astronomy, Inc.



 As one can see in Fig. 2, it is impossible to tell from the available data which minimum
is deeper, so we arbitrarily chose the better observed one to be set as a reference epoch.
With this convention an ephemeris for the subsequent times of primary minimum can be
written as

           T_min =HJD 2,448,724.8689 + 0.33885744d x E
                            +-0.0003 +-0.00000016


where E denotes the cycle number from the reference epoch. The uncertainties are quoted
at the 1 sigma level.

                            [FIGURE 2]

     Figure 2:   The phase diagram for the 0.33885744 orbital period




                           D. CIESLINSKI
                           F. J. JABLONSKI
                           e-mail: deo@das.inpe.br
                           chico @ das.inpe.br
                           Astrophysics Division
                           Instituto Nacional de Pesquisas
                           Espaciais
                           P.O. Box 515
                           12201-970 Sao Jose dos Campos/SP,
                           Brazil



  References:

Graham, J. A.,1982, PASP, 94, 244  [BIBCODE 1982PASP...94..244G ]
Steiner, J. E., Cieslinski, D., Jablonski, F. J., 1988, in Progress and 
    Opportunities in Southern Hemisphere Optical Astronomy, Vol. 1, p. 67, 
    eds. V. M. Blanco and M. M. Phillips [BIBCODE 1988ASPC....1...67S ]