COMMISSION 27 OF THE I. A. U.
         INFORMATION BULLETIN ON VARIABLE STARS
                      NUMBER 575

                                 Konkoly Observatory
                                 Budapest
                                 1971 August 23

Rosemary Hill Observatory, Department of Physics and Astronomy,
       University of Florida, Gainesville, Florida
                Contribution No. 25


                 PERIOD OF AQ TUCANAE


       The eclipsing binary AQ Tucanae (BV 423) was 
observed by the author on six nights in September, 1969, with
the number 1 16-inch telescope at the Cerro Tololo Inter-
American Observatory. The observations were made in three
colors with the use of standard UBV filters and a refrigerated 
1P21 photoelectric photometer.


----------------------------------------
Minima                Epoch       O-C
----------------------------------------
2438257.502(K&S)     -3732.5    -0.022
    263.490          -3722.5    +0.018
    297.364          -3665.5    -0.014
    309.322          -3645.5    -0.047
    314.322          -3637.0    -0.010
    314.367          -3637.0    +0.035
    339.293          -3595.0    -0.022
    641.497          -3087.0    +0.002
    695.294          -2996.5    -0.034
    695.340          -2996.5    +0.012
    701.258          -2986.5    -0.019
2440477.7731 (C)         0.0    -0.0012
    477.7737             0.0    -0.0006
    477.7761             0.0    +0.0018
    478.6656             1.5    -0.0010
    478.6658             1.5    -0.0008
    478.6686             1.5    +0.0020
    480.7482             5.0    -0.0003
    480.7483             5.0    -0.0002
    483.7230            10.0    +0.0003
    483.7223            10.0    -0.0004
    483.7229            10.0    +0.0002
    485.8040            13.5    -0.0007
    485.8052            13.5    +0.0005
---------------------------------------



       Koehler and Schoeffel published a list of minima in
IBVS no. 91 (1965) and obtained a period of 0.59480d. After
reducing the Cerro Tololo data a refined, compatible set of
light elements was found to be:

              JD 2440477.7743 + 0.59484267d
                          +-2         +-27

The two minima of AQ Tucanae are nearly equal and about
0.50m in V. The primary is about 0.48m and the secondary is
about 0.45m in B. Because of this identification of primary
and secondary eclipses is a problem. The identities of
primary and secondary of the observations of Koehler and
Schoeffel (or the authors) had to be reversed in order to
get a compatible set of light elements. The light curves
are currently being analyzed.



1971, August 9           THOMAS F. COLLINS

                      Rosemary Hill Observatory
                        University  of Florida