COMMISSION 27 OF THE I. A. U.
         INFORMATION BULLETIN ON VARIABLE STARS
                     Number 2310

                                    Konkoly Observatory
                                    Budapest
                                    11 April 1983

                                    HU ISSN 0374 - 0676



           PHOTOELECTRIC OBSERVATIONS OF TY Del


  The eclipsing binary TY Del (BD+12d4539) was discovered by Hoffmeister
(1934) who classified it as an Algol system. The best period to date has
been that of Ahnert (1973), who gives P = 1.1911204d. This variable has been
extensively observed photographically and visually, but the only photoelectric 
observations appear to be one time of minimum light reported by Pohl
and Kizilirmak (1972). Koch et al. (1979) called attention to the lack of
photoelectric observations to encourage further work on this system.
  For this reason TY Del was observed on five nights during the autumn of
1982 with the 40 cm telescope at the Morgan - Monroe Station of Goethe Link
Observatory. Differential measurements were made with standard UBV filters
along with a 1P21 photomultiplier tube cooled with dry ice. The comparison
star used was BD+12d4543 while BD+12d4542 was used as a check star.
  Unfortunately, only about half of the light curve was observed, giving
good definition of only primary eclipse. The Hertzsprung method was used to
determine three times of minimum light which are presented below. For each
eclipse a time of minimum light was determined for the observations in each
filter which were then averaged.



 JD Hel.   Min.   (O-C)
2445200+
------------------------
 16.6413   I     -.0002
 41.6545   I     -.0007
 53.5673   I      .0008
------------------------


These were combined with the minimum given by Pohl and Kizilirmak to form a
new set of light elements:

          Hel. Min. I= 2445216.6415 + 1.1911287d E
                                +-3         +-2

The residuals given above are computed for these light elements. This new
period agrees with previously published periods to the fifth decimal. It is
hoped that these revised light elements will assist others in planning 
observations of this star.



                         DANNY R. FAULKNER

                         Astronomy Department
                         Swain Hall West 319
                         Indiana University
                         Bloomington, IN 47405
                         U.S.A.



References:

Ahnert, P. 1973, I.B.V.S., No. 825.
Hoffmeister, C. 1934, Astron. Nachr., 255, 407. [BIBCODE 1935AN....255..401H ]
Koch, R.H., Wood, F.B., Florkowski, D.R., and Oliver, J.P. 1979, 
    I.B.V.S., No. 1709.
Pohl, E., and Kizilirmak, A. 1972, I.B.V.S., No. 647.