COMMISSION 27 OF THE I. A. U.
           INFORMATION BULLETIN ON VARIABLE STARS
                        Number 2599

                                             Konkoly Observatory
                                             Budapest
                                             8 October 1984

                                             HU ISSN 0374-0676

   PHOTOELECTRIC OBSERVATIONS OF THE RECENT ECLIPSE OF 22 VULPECULAE

   The spectroscopic binary 22 Vulpeculae (BD +23d3944) was. noted by Parsons
and Ake (1983 Inf. Bull. Var. Stars No. 2334) to have recently undergone an
eclipse. Their conclusion was based upon IUE spectra from April 1983 in which
the spectrum of the hotter companion was absent and the FES magnitude 
(lambdaEFF 5200 A) was 0.12 magnitude fainter than on previous occasions. With a
revised period they gave the approximate ephemeris:
                2445442.2 + 249.099E.
   To confirm 22 Vul as an eclipsing binary, it was observed on seven nights
during August and September 1984 with the 41 cm. reflector of the Morgan-Monroe
station of the Goethe Link Observatory. All observations were made with standard
UBV filters and a 1P21 photomultiplier tube cooled with dry ice. Differential
measurements were made in the pulse counting mode using BD +24d4075 as a 
comparison star and BD +23d3935 as a check star. A neutral density filter was
used to reduce the brightness of the stars involved. Calculation showed that
the largest dead time correction was less than 0.5%, hence dead time corrections
were not applied. Because the variable and comparison stars are separated by
more than 1deg, corrections for differential extinction were applied. No attempt
was made to transform to the standard system. The check star varied by less than
+-0.01m in B and V and less than +-0.02m in U.
   The differential magnitudes are plotted in Figure 1. From this plot several
conclusions can be drawn:
   1. An eclipse did occur.
   2.The depth of the eclipse was approximately 0.05m in V, 0.10m in B and
     0.30m in U.
   3. Duration of totality was at least eight days, as noted by Parsons and Ake.
   4. Mid-eclipse occurred no earlier than J.D. 2445941.6, more than a day
     later than predicted by the above light elements.


                             [FIGURE 1]




                                      DANNY R. FAULKNER
                                      Astronomy Department
                                      Swain West 319
                                      Indiana University
                                      Bloomington, IN 47405 U.S.A.