COMMISSION 27 OF THE I. A. U.
            INFORMATION BULLETIN ON VARIABLE STARS
                         Number 3408

                                               Konkoly Observatory
    	                                       Budapest
        	                               27 December 1989

                	                       HU ISSN 0374 - 0676


TIMES OF MINIMUM LIGHT FOR 16 ECLIPSES OF 8 APSIDAL MOTION BINARIES

    We report here on the continuation of a program of observing
eclipsing binary systems suggested by Gimenez and Delgado (1980),
and by Giminez (1985), as candidates for possible detection of
general-relativistic apsidal motion.
    The observations were made with the 46-cm reflector at
Appalachian State University's Dark Sky Observatory. The
photometer is a Kitt Peak National Observatory single-channel
design employing a thermoelectrically cooled EMI 9865QB
photomultiplier tube with matching UBVR filters. An Astronomical
Time Mechanisms Model 240V amplifier provides a voltage-to-
frequency output that is integrated by a microcomputer.
    The observations for a given eclipse were made through one
filter only, to maximize the number of data points. The
observations have not been transformed to the Johnson system,
since they were only intended for timing analysis. The
observations are available from the IAU Archives, file number
212.

    The times of minimum light and standard errors given in
Table I were calculated using the method of Kwee and van Woerden
(1956), using a program written by Ghedini (1982). This
algorithm has been shown by Caton (1989) to give the most
accurate estimation of time of conjunction for asymmetric light
curves.


                   Table I.

 System Type of Heliocentric JD Comparison Filter
        Eclipse   -2400000      Star
TV Cet  Primary 47147.58576     BD +01d566   V
                 +/-0.00022


EK Cep  Primary 46724.79762     BD +68d1239  R
                 +/-0.00013

        Primary 47499.66257      " " "       V
                 +/-0.00012


CO Lac Primary  47084.64270     (see Note 2) V
                 +/-0.00050

       Secondary 47097.74215     " " "       V
                  +/-0.00015

       Secondary 47495.63488     " " "       V
                  +/-0.00022

       Primary  47502.57676      " " "       V
                 +/-0.00019

RR Lyn Secondary 47220.67251     BD +56d1136 V
                  +/-0.00049

       Secondary 47568.75226     " " "       V
                  +/-0.00038


V451 Oph Primary 47307.73282     BD +10d3526 V
                  +/-0.00035

       Primary  47654.79386      " " "       V
                 +/-0.00028

FT Ori Primary  47132.84835     BD +21d1161  V
                  +0.00024

       Primary  47507.74782     " " "        V
                 +/-0.00012


AG Per Secondary 97480.67474    BD +33d776   V
                  +/-0.00024

       Primary  47495.79985     " " "        V
                 +/-0.00030

IQ Per Primary  47102.72767     BD +47d923   V
                 +/-0.00029


Notes
1)    It was noted in preparation for observing EK Cep that this
    system is misidentified in A Finding List for Observers of
    Interacting Binary Stars (Wood, et al., 1980). EK Cep is
    incorrectly identified as BD +69d1197 (their entry number
    N = 3255), with BD +69d1191 entered as entry number N =
    3254, a system of unknown period. Apparently these are the
    same system EK Cep = BD +69d1191.

2)    For CO Lac, the star marked "C" in the finding chart,
    (Figure 1), was used for the comparison. It also appears
    that CO Lac itself is incorrectly identified in A Finding
    List for Observers of Interacting Binary Stars (Wood, et
    al., 1980), with BD +56d2857, which is a few minutes to the
    north-west of the variable. This star was initially tried
    as a comparison but seemed to be varying on a short time
    scale. The star marked "K" was used for the check.


                         [FIGURE 1]


   We gratefully acknowledge the assistance of F. B. Wood and
G. Fitzgibbons in providing reference material from the
University of Florida Card Catalogue of Eclipsing Binaries. We
also thank J. T. Pollock for the CCD image used for the finder
chart production and in the identification of CO Lac. This
project was also partially supported by NSF Grant AST-8705770.



            DANIEL B. CATON
            R. LEE HAWKINS
            WANDA C. BURNS


            Dark Sky Observatory
            Department of Physics and Astronomy
            Appalachian State University
            Boone, North Carolina 28608 U.S.A.



References:

Caton, D. B. (1989), Bull. A. A. S. 21, No. 1, 714. [BIBCODE 1989BAAS...21R.714C ]
Ghedini, S. (1982). Software for Photometric Astronomy, Willman-
    Bell, Richmond, VA, p. 46. [BIBCODE 1982spa..book.....G ]
Gimenez, A. (1985). Astrophys.J. 297, 405. [BIBCODE 1985ApJ...297..405G ]
Gimenez, A. and Delgado, A. (1980), IAU Inf. Bull. Var. Stars, No. 1815.
Kwee, K. and van Woerden, H. (1956). B.A.N. 12, 327. [BIBCODE 1956BAN....12..327K ]
Wood, F.B., Oliver, J.P., Florkowski, D.R., and Koch,
    R.H. (1980). A Finding List for Observers of Interacting
    Binary Stars, University of Pennsylvania Press.


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