COMMISSION 27 OF THE I. A. U.
        INFORMATION BULLETIN ON VARIABLE STARS
                    Number 1781

                                Konkoly Observatory
                                Budapest
                                1980 May 9


           IMPROVED EPHEMERIS, UX ERIDANI


UX Eridani (BD-7d553) is a W UMa-type eclipsing binary system which undergoes
partial eclipses. Photoelectric B, V observations were obtained with the 0.6
meter telescope at Cerro Tololo Inter American Observatory in December 1979.
BD-7d551 was observed as the comparison star. The observations define a
secondary eclipse curve. The following epoch of minimum light was determined
by an iterative technique based on the Hertzsprung (B.A.N. 4, 179, 1928)
method,

JD Hel. Min. II = 2444228.6458.

Table I lists all the photoelectric times of minimum light that have been
published for this system. The O-C's were calculated from the ephemeris
published by Binnendijk (A.J. 72, 82, 1966), namely,

JD Hel. Min. I = 2438700.7228+0.44528226d E.

An improved ephemeris for the system is

JD Hel. Min. I = 2441922.3195+0.44527942d E.

Table I

JD Hel.        Min.    O-C         Reference
2434358.101     II   -0.007        Annals Tokyo Obs. 5, 23, 1957
   4369.015     I    -0.002        "
   5097.053     I     0.000        "
   8700.7228    I     0.0000       A.J. 72, 82, 1966.
   8727.6635    II   +0.0011       "
2441922.5394    II   -0.0232       I.B.V.S. No. 937, 1974.
   4228.6458    II   -0.0336       - - - - -

A reanalysis of the system is underway.


BEVERLY B. BOOKMYER
P.A. BASILICO
Department of Physics and Astronomy
Clemson University
Clemson, SC 29631 USA