COMMISSION 27 OF THE I. A. U.
          INFORMATION BULLETIN ON VARIABLE STARS
                       Number 2895


                                        Konkoly Observatory
                                        Budapest
                                        14 May 1986

                                        HU ISSN 0374-0676



    BEHAVIOUR OF THE X-RAY BINARY V 1727 CYGNI = 4U 2129+47 IN 1985


   In monitoring the behaviour of V 1727 Cyg the star was inspected on 60
blue-sensitive plates (ORWO-ZU21+GG13+BG12) from 35 nights obtained with the
Schmidt camera 50/70/172 cm of Sonneberg Observatory covering the time interval
between 22 March 1985 and 31 December 1985. The individual estimates, which are
summarized in Table I, are linked to the sequence of comparison stars given by
Wenzel (1983). On most of the plates the star is below the limiting magnitude.
The object is visible only on 19 plates. There, its brightness varies between
mB = 18.0m and mB = 18.4m. The behaviour given here characterizes the low or
inactive state of the star which probably started near 7 September 1983 (Wenzel,
1983).
   The observations listed in Table I are shown in Figure 1.
They are reduced to one common epoch by means of the elements:

          Min(hel.) = 2444403.743 + 0.2182579d E

given by McClintock et al. (1982). The arrows indicate "fainter than" observations


                               [FIGURE 1]


	Table I


J.D. hel.    m(B)     Rem.    
244....

6147.591    18m0:	
6147.610  > 17.5	iv
6173.569  > 17.9	iv
6173.587  > 17.5	iv
6175.550  > 17.5	iv
6175.569  > 17.5	iv
6177.558  > 17.9	iv
6177.575  > 17.9	iv
6200.496  > 17.9	iv
6200.515    18.3	
6210.502  > 17.9	iv
6260.475    18.1
6260.495    18.2
6260.514  > 17.5	iv
6269.597  > 17.9	iv
6261.536    18.2
6264.529    18.3
6264.540    18.3
6270.548  > 17.9	iv
6271.520  > 17.9	iv
6271.538  > 17.9	iv
6272.516  > 17.9	iv
6272.536    18.3
6272.554  > 17.9	iv
6288.411  > 17.9	iv
6288.430    18.2
6291.434  > 17.9	iv
6292.423  > 17.5	iv
6292.443    18.3
6293.505  > 17.9	iv
6296.469  > 17.9	iv
6296.488  > 17.9	iv
6298.490  > 17.9	iv
6298.509  > 17.9	iv
6299.477  > 17.9	iv
6299.497  > 17.9	iv
6320.477  > 17.9	iv
6320.496  > 17.9	iv
6321.486  > 17.9	iv
6329.505    18.1
6327.441    18.4
6327.459    18.4
6328.438    18.4
6328.458  > 17.9	iv
6351.376  > 17.9	iv
6355.383  > 17.9	iv
6358.324  > 17.9	iv
6360.371    18.4
6373.271    18.4
6373.291    18.3
6374.273    18.3
6374.295    18.4
6385.293  > 17.5	iv
6386.294  > 17.9	iv
6387.398  > 17.9	iv
6404.233  > 17.9	iv
6404.253  > 17.9	iv
6405.250  > 17.9	iv
6431.225  > 17.9	iv
6431.238  > 17.9	iv

iv = invisible


                                   W. GOTZ
                                 Akademie der Wissenschaften
                                 der DDR, Zentralinstitut fur
                                 Astrophysik, Sternwarte Sonneberg
                                 DDR




References:

Wenzel, W., 1983, I.B.V.S., No. 2452
McClintock et al., 1982, Astrophys. J. 258, 245 [BIBCODE 1982ApJ...258..245M ]