The International Supplement (SAC - Supplemento ad Annuario Cracoviense) contains ephemerides for one year that include 880 stars recognized as eclipsing binaries (of Algol, beta Lyrae, or W Ursae Maioris type), satisfying the following conditions:

1. a given star is included in the third edition of the General Catalogue of Variable Stars, Moscow 1969, (GC 69), or in the Supplements to GC 69;
2. the period of light variation and the time of primary minimum are well determined;
3. brightness in maximum exceeds 8.0 magnitudo, with any light variation amplitude, or maximal brightness is greater than 10.7 magnitudo and the amplitude is no less than 0.7 magnitudo.

Some other eclipsing binaries have been also taken into consideration, following the requirements submitted by observers.

The additional list of eclipsing binaries, compiled by Mrs. E.Danielkiewicz-Krosniak, has been further supplemented and updated.

In order to avoid undue enlarging the book, which would make its use much less convenient, the ephemerides containing all minima to occur in the year are arranged, as in the previous issues of SAC, into three schemes, according to period length.

The ephemerides provide heliocentric moments of minima, predominantly primary ones, expressed in Universal Time in units of 0d01. Secondary minima, indicated by underlining, are given for the following 46 stars: XZ Ant, BW Aqr, V 337 Aql, V 889 Aql, V 539 Ara, RS Ari, WW Aur, ZZ Boo, AS Cam, UU Cnc, SW CMa, UW CMa, GL Car, PV Cas, NP Cen, V 498 Cen, WX Cep, AI Cep, CW Cep, EI Cep, TV Cet, V 454 CrA, Y Cyg, V 380 Cyg, V 477 Cyg, V 541 Cyg, RX Dra, UZ Dra, DI Her, SS Lac, CO Lac, GG Lup, RR Lyn, RU Mon, Z Nor, EW Ori, GG Ori, AG Per, YY Sgr, V 526 Sgr, V 1647 Sgr, V 2283 Sgr, V 457 Sco, CD Tau, CV Vel, and DR Vul.

Half-times of eclipse duration (1/2D) or variability type designations are given at the bottom of each ephemeris table (beta = beta Lyrae-type, W = W Ursae Maioris-type).

A table for converting decimal fractions of day into hours and minutes is enclosed in the form of a separate doubled card, which can well be used as a book-mark. The card contains also Julian Dates (JD) as well as Modified Julian Dates (MJD) for the year.

The ephemerides for 415 binaries of short period (less than 2d00) are given in the special pattern introduced by Dr. K.Kordylewski in SAC 5 in 1926. Any required moment of minimum can be obtained by taking the number corresponding to the day of month from the upper part of the table (term a) and adding it to the number corresponding to the month from the lower part of the table (term b). The upper part contains multiples of period calculated for each day of each particular month, while the lower part yields the first day of month in units of 0d01.

The ephemerides for 135 binaries of long period (more than 7d00) include explicitly all minima of those stars to occur in the year.

In the case of binaries of extremely long period (epsilon Aur, dzeta Aur, AZ Cas, VV Cep, EE Cep, V 695 Cyg, V 1488 Cyg, BL Tel) the phase values are expressed as a fraction of period at the beginning and at the end of the year respectively, as well as the date of the middle of eclipse if it is to occur during the year.

The last two columns contain half-times of eclipse duration (1/2Dh) and half-times of least light duration (i.e. half of the flat bottom part of light curve - 1/2dh).

This section includes 330 binaries of intermediate period (between 2d00 and 7d00). Ephemerides for one month cover 4 pages.

The first column on each page contains succesive days of month. The last column in the last table for each month contains Julian Dates corresponding to the days of the month, the first three figures being given in the heading.

The list of binaries included in the ephemerides b, l, and m is given, its columns containing respectively:

1. a star's name or designation; the stars are arranged in the alphabetical order of their contellation names, the stars with Bayer and Flamsted designations being listed last of all;
2. and
3. mean equatorial coordinates for the epoch 2000, alpha2000 and beta2000, which are convenient for setting the coordinate circle of observation instrument;
4. the moment of minimum assumed in calculating the ephemeris, expressed in JD; secondary minima are indicated by underlining;
5. the value of period used in calculating the ephemeris; due to period variability, the elements given in columns 4 and 5 are not appropriate for any long-term calculating of observations. In the cases that ephemerides were based on elements involving terms in higher order of E or periodic terms (GL Car, RX Cas, SV Cen, Y Cyg, V 380 Cyg, RT Lac, AR Lac, CO Lac, beta Lyr, AT Peg, RW Per, V 526 Sgr, V 2283 Sgr), mean linear elements were determined, so the moment given in Column 4 for the those stars has not been derived from observations and the value of period in Column 5 is a theoretical value for the given epoch. Also in the case of A.D. Mallama's elements, the moments of minima given in Column 4 are theoretical ones.
6. the authority for the ephemeris basis; when more than one source is given, the former one will pertain to the moment of minimum and the latter to the period; in most cases, the elements and other data were taken from the General Catalogue of Variable Stars; all the abbreviations used are explained; due to space limitation, the author's name is cited explicitly only for single authorship;
7. maximum brightness, M, in stellar magnitude units;
8. and
9. light variation amplitude in the primary minimum A1, and in the secondary minimum A2, in stellar magnitude units;
10. designation of the photometric system used; the letters v, p, and B, V, denote that both the maximum brightness and the light variation amplitude were obtained through visual, photographic, or photoelectric measurements respectively;
11. total duration time of primary eclipse, D, in hours, or, in particular cases, in days; the stars of beta Lyrae type, for which D cannot be determined from their light curve, are denoted as beta, while the cases of almost equal A1 and A2, the period being shorter than one day (as in W Ursae Maioris), are denoted as W;
12. duration of stationary phase (flat bottom of light curve, i.e. total eclipse phase), in hours, or in particular cases, in days;
13. the year in which the most recent minimum available was published;
14. the scheme in which the ephemeris has been calculated.

We offer due thanks to all who by sending us data from new observations of eclipsing binaries contributed to SAC, enabling us to introduce more element modifications.

Cracow, November 1997
E.Danielkiewicz-Krosniak
M.Kurpinska-Winiarska
Jagiellonian University
Observatory

For computing the ephemerides, the stars were selected along the following principles:

1. a given star is not fainter than 11.6 magnitudo at maximum (except 4 stars);
2. amplitude of light variation is greater than 0.3 magnitudo.

The ephemerides are accompanied by a revised catalogue containing elements of 237 stars. The source of data concerning physical properties of stars is the 4th edition of General Catalogue of Variable Stars (Moscow 1985). The last column of the list gives the year of the last observations used in revising the elements. The minus sign (-) denotes that the revision of the elements was not possible due to insufficient observational data. Those stars deserve particular attention from observers.

In the revision of elements, stars with considerable period changes have been detected. For these stars, the list gives elements from which a reliable ephemeris can be computed for a short time ahead. The stars showing secular changes in period are marked with +, and those manifesting the Blazhko effect with x.

Cracow, June 1995
B.Zakrzewski
Institute of Physics
Pedagogical University
ul. Podchorazych 2
30-084 Cracow

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