COMMISSION 27 OF THE I. A. U.
           INFORMATION BULLETIN ON VARIABLE STARS
                       Number 2556

                                        Konkoly Observatory
                                        Budapest
                                        20 July 1984

                                        HU ISSN 0374-0676

         PHOTOGRAPHIC OBSERVATIONS OF AT Cnc IN 1983/84

 Photographic observations of AT Cnc were carried out in November, 1983
through March, 1984, with 18-cm Schmidt camera in two colours. 103a-O emulsion 
with sharp cut filter at 3900A, and Tri-X emulsion with yellow-green
filter were used for photographic and visual magnitudes, respectively. The
photographic magnitudes of comparison stars by Gotz (1983) were used, and
their visual magnitudes were determined by the author. The results are shown


                                [FIGURE 1]


in Figure 1, in which photographic magnitudes are by dots and visual 
magnitudes by crosses.
  The light curve shows fairly regular variation with the period of 12.5d.
The amplitudes are 12.5m-16.0m (visual) and 12.5m-16.5m (photographic). I like
to point out that the light curve is very much similar to that of the dwarf
nova and X-ray emitting star, HL CMa, in their amplitude, period and the
behavior of variation, having broad and narrow maxima irregularly.


                   M. HURUHATA
                   Hodozawa 88,
                   Gotemba-shi,
                   412 Japan

Reference:
Gotz, W., 1983, I.B.V.S. No. 2363