COMMISSIONS 27 AND 42 OF THE IAU
               INFORMATION BULLETIN ON VARIABLE STARS
                            Number 4038

                                                  Konkoly Observatory
                                                  Budapest
                                                  1 June 1994

                                                  HU ISSN 0374 - 0676

                   CALL FOR OBSERVATIONS OF BH Cas

  Observations of BH Cas were collected on 19 February 1994 from the Steward 
Observatory 0.91-meter telescope on Kitt Peak. Nine frames were obtained over a period of
~ 1.3 hours using a Tektronics 2048 x 2048 CCD (no filter). The IRAF routine imexamine
was used to gather the background-subtracted fluxes of BH Cas and of the reference and
check stars, GSC 01629 and GSC 01134 respectively. The data is given in Table I.


           Table I : Flux Values

   UT      BH Cas  GSC 01629   GSC 01134
02:48:40   265568   121795      96509
02:59:24   262178   118351      93634
03:08:06   265406   116603      93170
03:17:21   272431   116974      93379
03:25:54   280967   118128      93628
03:33:31   270747   113479      90062
03:44:07   281462   116563      92990
03:52:19   268233   111837      88710
04:05:38   262414   108613      86909

  Plots of flux ratio against time were made in order to detect any possible variation
in the brightness of BH Cas. In Figure 1 the ratio of the flux of BH Cas to that of the
reference star is shown; in Figure 2 the ratio of the flux of the reference star to that of
the check star is shown. Both figures are plotted to the same vertical scale.


                              [FIGURE 1]

                  Figure 1. BH Cas / GSC 01629

                              [FIGURE 2]

                 Figure 2. GSC 01629 / GSC 01134


 The discovery observations of the variability of BH Cas were made by Beljawsky ( 1931 )
and were confirmed by Kukarkin (1938) who concluded that the star was possibly of
W UMa type with period ~0.5d and amplitude ~0.4m. A later paper by Ahnert and
Hoffmeister (1943) concluded that no star in the given area showed variation in brightness.
No published observations of BH Cas have appeared since that time until this paper.
Although further investigation is necessary, it is questionable whether the conclusion of
Ahnert and Hoffmeister is valid.
 The presence of a star of appreciable brightness within 10 arcseconds of BH Cas poses
a potential problem for accurate photoelectric observations. An attempt will be made
to use a CCD with filters designed to produce a standard (U,B,V) response in order to
reconstruct the entire light and color curves. Please contact the undersigned for finder
charts or additional information.


                          T.S. METCALFE
                          Department of Astronomy
                          University of Arizona
                          Tucson, Arizona, USA
                          tmetcalf @ astro.as.arizona.edu



References:
Ahnert, P., Hoffmeister, C., 1943, K.V.B.B., 28, 4
Beljawsky, S., 1931, A.N., 243, 115 [BIBCODE 1931AN....243..115B ]
Kukarkin, B.W., 1938, N.N.V.S., 5, 195