COMMISSION 27 OF THE I. A. U.
             INFORMATION BULLETIN ON VARIABLE STARS
                         Number 2815

                                             Konkoly Observatory
                                             Budapest
                                             4 November 1985

                                             HU ISSN 0374 - 0676


             THREE-COLOUR PHOTOELECTRIC LIGHT CURVES
              OF THE ECLIPSING BINARY RS VULPECULAE


  The eclipsing binary RS Vul (BD+22deg3647) was observed photoelectrically
between 19 June and 12 November, 1982 on 50 nights with the 30 cm Maksutov
telescope of Ankara University Observatory. A total of 178 (181 in U colour)
observations was obtained in ultraviolet, blue, and yellow lights. An RCA 1P21
photomultiplier and UBV filters, which are close to the standard UBV system, 
were used.
  BD+21deg3740 and BD+21deg3719 were used as comparison and check stars, 
respectively. The light curves are shown in the Figures 1, 2, 3, where the individual
magnitude differences were formed in the sense comparison minus variable, have
been plotted against the phases which were calculated with the light elements
given below :

         Min I = JD Hel. 2445 229.298+4.4776635d E

where the value of T0 was determined from the present observations, and the
period was taken from G.C.V.S. (1969).

  A glance at the light curves clearly indicates that the depth of the 
secondary minimum becomes more pronounced towards longer wavelengths. The 
observations are relatively deficient at about phases 0.94, 0.04, and 0.52. 
The depths of the primary minima are about 1.10m, 1.07m, and 1.00m in the U, 
B, V colours, respectively. Due to the relative scattering of the observations 
at U, the depth of the secondary minimum could not be determined properly. 
However, the depths of the secondary minima at B and V were observed to 
be 0.10m and 0.11m, respectively. The observed depths of the primary 
minima of the system
from the present light curves are in good agreement with the earlier ones
except given by Popper (1957) (DeltaB and DeltaV approx. 0.65).

  Figures 4 and 5 show the colour variations of RS Vul with respect to the 
comparison star.

  I would like to express my many thanks to Dr. Zeki Aslan, for his helpful
suggestions and valuable advice.


                              [FIGURE 1]

             Figure 1. The U light curve of RS Vul

                              [FIGURE 2]

             Figure 2. The B light curve of RS Vul

                              [FIGURE 3]

             Figure 3. The V light curve of RS Vul

                              [FIGURE 4]

             Figure 4. The (U-B) variation of RS Vul

                              [FIGURE 5]

             Figure 5. The (B-V) variation of RS Vul



                           V. KESKIN
                           1746 Sokak No. 8
                           Kat. 2, Daire 4
                           Karsiyaka, IZMIR
                           Turkey




References:

Hutchings, J.B., and Hill, G., 1971, Ap. J., 166, 373. [BIBCODE 1971ApJ...166..373H ]
Popper, D.M., 1957, Astrophys. J., Suppl., 3, 107. [BIBCODE 1957ApJS....3..107P ]