COMMISSION 27 OF THE I. A. U.
          INFORMATION BULLETIN ON VARIABLE STARS
                      Number 2720


                                          Konkoly Observatory
                                          Budapest
                                          14 May 1985

                                          HU ISSN 0374 - 0676




             PHOTOELECTRIC OBSERVATIONS OF PW Vul



 A set of photoelectric observations of Nova Vul 1984. No. 1 (now designed
as PW Vul) was carried out at the University Observatory in Brno on 4 nights
during August - September 1984. The observations were made with the 60 cm
reflector and photoelectric photometer equipped with UBV filters and EMI
6256S photomultiplier. The data of the comparison stars are given in Table I.
The UBV data of all comparison stars were derived in the usual way from UBV
standards near PW Vul. From our measurements it follows that all these 
comparisons are constant.

                             Table I

    Object                    BD        SAO     V     B-V   U-B
Comparison star A         +27deg3391    87213 7.460 +0.550 -0.040
Comparison star B         +27deg3400    87257 8.987 +0.153 -0.158
Comparison star C         +27deg3390    87211 9.675 +0.210 -0.325

The mean errors of the photometry are 0.007 mag for comparisons A and B, and
0.011 mag for comparison C, respectively.

  The Nova PW Vul was measured differentially to comparison A. The means of
individual observations were grouped into normal points and are listed in
Table II. Our measurements in V colour are plotted in Figure 1, where other
published UBV observations are plotted too.

  From Figure 1 it is clear that after the first outburst the brightness of
PW Vul changed with an amplitude of about 1.5 mag on the time scale 6-7 days.

  Individual observations in V colour (on the night 28/29.8) are plotted in
Figure 2. Two different changes in brightness are present here:
  1. small fluctuations in the range 0.03-0.04 mag during 5-6 minutes
  2. changes in the range 0.15-0.20 mag during 2-3 hours (observed by Noskova
    (1984) and Schult (1984), too).

The character of the light variations in B and U colours is the same as in V.


                               [FIGURE 1]

          Figure 1   The light curve of PW Vul in V colour

                               [FIGURE 2]

    Figure 2   The light changes of PW Vul during one observational night





                   Table II
J.D.
2440000+   V       B-V      U-B       N
5940.384   8.146   +0.543   -0.476   13
    .392   8.265    -        -       14
    .411   8.257   +0.431    -       22
5941.299   7.931   +0.410   -0.544   27
    .361   7.898   +0.413   -0.540   32
    .375   7.902    -        -        5
    .396   7.927   +0.404   -0.551   21
    .433   7.912    -        -        7
    .453   7.789   +0.422   -0.493   15
    .489   7.818   +0.406   -0.514   14
5945.299   7.605   +0.430   -0.512   21
    .325   7.643   +0.444    -       17
    .333   7.643    -        -        9
5948.299   8.178   +0.375   -0.550   34
    .317   8.214   +0.356    -       18
    .371   8.182   +0.370   -0.600   26
    .442   8.160   +0.361   -0.570   22




J. PAPOUSEK

Department of Astronomy
Brno University
Kotlarska 2
611 37 Brno, CSSR



References:
IAU Circ. 3976 (1984) [BIBCODE 1984IAUC.3976....1R ]
Noskova, R.I.: 1984, Astron Tsirk. No. 1348, 1. [BIBCODE 1984ATsir1348....1N ]
Schult, R.H.: 1984, I.B.V.S. No. 2578
Taranova, O.G. et al.: 1984, Astron Tsirk. No. 1348, 3. [BIBCODE 1984ATsir1348Q...3T ]