COMMISSION 27 OF THE I. A. U.
         INFORMATION BULLETIN ON VARIABLE STARS
                     Number 2274

                                     Konkoly Observatory
                                     Budapest
                                     1983 February 1

                                     HU ISSN 0374-0676



       PHOTOELECTRIC OBSERVATIONS OF AT Cam AND AZ Cam



  B,V light curves of the eclipsing binary systems AT Cam and AZ Cam
(BD +82deg0263) were observed photoelectrically in December 1981 and January
1982 with the 60 cm telescope at Peking Astronomical Observatory.

  The comparison star and check star are given in Table I.

                    Table I

            Comparison star and check star

                     BD No.    R.A.(1981)   Dec.(1981)
Comp. star of AT Cam           5h36m21s     67deg01'37"
Check star of AT Cam           5 38 41.5    66   59 02
Comp. star of AZ Cam 82deg0264
Check star of AZ Cam 82deg0261

  All the observations for these binaries were corrected for differential
extinction. The Kwee and Van Woerden's method was used to determine the
times of minimum light. Table II lists the times of minimum light of AT Cam
and AZ Cam.

                   Table II

        The times of minimum light of AT Cam and AZ Cam

  Star   JD Hel.      m.e.     Filter   rem.
         2400000+

AT Cam   44959.2884   0.0005   V        I
         44959.2875   0.0006   B        I
         44983.0155   0.0004   V        I
         44983.0220   0.0004   B        I
AZ Cam   44985.1908   0.0005   V        I
         44985.1908   0.0005   B        I
         44987.1744   0.0005   V        II
         44987.1688   0.0005   B        II

  The B light curves are shown in the accompanying diagrams (Fig. 1 and Fig. 2).
These light curves of AT Cam and AZ Cam are similar, the primary and 
secondary minima have practically the same depth.

                           [FIGURE 1]

             Figure 1: B light curve of AT Cam

                           [FIGURE 2]

             Figure 2: B light curve of AZ Cam


  On the basis of earlier and our observations we have computed the new
elements of AZ Cam, obtaining:

            JD Hel. Min I = 2444985.908 + 1.3192299d E
  The probable errors obtained from a least squares solution for these
quantities were +/- 0.0005 for the initial epoch and +/- 0.0000004 for the period.

  These light curves should be analysed in more detail subsequently.


         ZHAI DI SHENG, ZHANG RONG XIAN and ZHANG JI TONG

             Peking Astronomical Observatory

                    CHINA




           [Corrigenda from IBVS 2651]

		Corrigenda

---------------------------------------------------
IBVS No.   Page   Line	 incorrect     correct
---------------------------------------------------
2274	   2	  3	 2444985.908   2444985.1908
2275	   1	  7	 four times    three times
2275	   1	  8	 four times    three times
---------------------------------------------------




		  ZHAI DI-SHENG, ZHANG RONG-XIAN,
		  ZHANG JI-TONG,
		  Beijing Astronomical Observatory, China