COMMISSION 27 OF THE I. A. U.
          INFORMATION BULLETIN ON VARIABLE STARS
                      Number 2804

                                      Konkoly Observatory
                                      Budapest
                                      4 October 1985

                                      HU ISSN 0374 - 0676



      PHOTOELECTRIC EPOCHS OF MINIMUM LIGHT OF SY HOROLOGII


   The first photoelectric observations of SY Horologii (= S 4832 =
CoD - 46deg 1350) were obtained in January 1981 with the 0.6-m telescope
at Cerro Tololo Inter-American Observatory in Chile. Differential
measurements in B and V were made on seven nights resulting in 540
individual observations in each bandpass. Each observation is an
average of two ten second integrations.
   An iterative process based on the method of Hertzsprung (1928) was
applied to the present observations to determine the epochs of minimum
light listed in Table I. Earlier visual and photographic timings of
minimum light of SY Hor have been published by Hoffmeister (1956).
   The O-Cs were computed from the ephemeris

        Min I (Hel. J.D.) = 2444613.6335 + 0.31164361d E
                          +-       .0001 +- .00000005 (p.e.)  
                  
which was derived by a least squares analysis using all the available
data and weighting the times of minima 10 to 3 to 1, photoelectric to
photographic to visual.
   The observations, period study, and analyses of the light curves
are being published separately.

                     TABLE I


             TIMES OF MINIMA FOR SY Hor


HEL.J.D.        MIN   EPOCH       O-C      FILTER

2444609.58233     I  -13.0       -0.0002   B,V
2444611.60752    II   -6.5        0.0003   B,V
2444613.63385     I    0.0       -0.0004   B,V
2444615.65874    II    6.5        0.0004   B,V
2444618.62002     I   16.0       -0.0002   B,V
 
 
                            
                      J.R. KERN* and BEVERLY B. BOOKMYER
                      Dept.of Physics and Astronomy
                      Clemson University
                      Clemson, SC 29631, U.S.A.
                      
                       * Present Address:
                      Dept.of Physics
                      Rochester Institute of Technology
                      Rochester, NY 14623, U.S.A.

References:

Hertzsprung, E., 1928, Bull. Astr. Inst. Netherlands 4, 179. [BIBCODE 1928BAN.....4..172H ]
Hoffmeister, C., 1956, Veroeff. Sonneberg, 3, (1), 7, 17. [BIBCODE 1956VeSon...3....1H ]