COMMISSION 27 OF THE I. A. U.
         INFORMATION BULLETIN ON VARIABLE STARS
                     Number 1875

                                   Konkoly Observatory
                                   Budapest
                                   1980 December 3

                                   HU ISSN 0374-0676

        PHOTOELECTRIC TIMES OF MINIMA OF TT Her


  On years 1978 and 1979, about 4500 U-B-V photoelectric observations 
of the eclipsing binary TT Her (BD +17d3117)were performed 
at the Teramo Observatory. The observations will be published
elsewhere.
  The photometric equipment is a single-channel pseudo-multiband 
photon-counting photometer which is controlled by a DEC PDP
11-minicomputer.
  The photometer is attached to the Nasmith focus of the 50 cm
Askania reflector of the Capodimonte Astronomical Observatory in
Naples stationed at Teramo. An EMI 6506 photomultiplier has been
used with Schott filters GG14+GG13 (2mm) for V, BG12 for B and
UG2 for U.
  Six times of minima have been calculated by means of the Kwee
and Van Woerden method (1956) from the data at our disposal. By
a differential correction procedure it was computed a linear ephemeris, 
taking also into account other data from the literature
(van Genderen, 1969; Pohl and Kizilirmak, 1972). The linear ephemeris 
we obtained is:

       Hel. J.D. Min.I = 2444025.4596 + 0.91207838 E         (1)
                                  +-7         +-11
   In the Table below are listed the times of minima, their
(O-C)'s from (1) and the standard deviation sigma of each time of
minimum:

J.D.2400000+     E     O-C        sigma
44015.4245     -11   -0.0023  +-0.0013
44015.4262     -11   -0.0005    0.0004
44015.4254     -11   -0.0013    0.0007
44025.4547     0     -0.0049    0.0025
44025.4599     0     +0.0004    0.0010
44025.4574     0     -0.0022    0.0011


                    A. D'ORSI, S. MARCOZZI, L. MILANO
         Capodimonte Astronomical Observatory, Naples, Italy

References:
Genderen van, A.M.: 1962, Bull. Astron. Neth. 16,151 [BIBCODE 1962BAN....16..151V ]
Kwee, K.K., van Woerden, H.: 1956, Bull. Astron. Neth. 12,327 [BIBCODE 1956BAN....12..327K ]
Pohl, D., Kizilirmak, A.: 1972, I.B.V.S. No. 647