COMMISSION 27 OF THE I. A. U. INFORMATION BULLETIN ON VARIABLE STARS NUMBER 871 Konkoly Observatory Budapest 1974 February 28 OBSERVATIONS AND PRELIMINARY PERIODS FOR VARIABLE STARS IN NGC 1261 Two series of B(103aO + GG 385) plates of the globular cluster NGC 1261 were taken in December 1971 and November 1972 with the 24-inch (60 cm) telescope of the University of Toronto at Las Campanas, Chile. In addition, the authors were lent two plates of the same cluster taken with the same telescope in September 1971 by W. Harris of the University of Toronto. The plates were measured with the Becker iris photometer of the University of Western Ontario and the magnitudes determined using the photoelectric sequence of Alcaino and Contreras (Astr. Astroph., 11, 14, 1971) are listed in Table I. Combining these magnitudes with those published by Bartolini, Grilli and Morisi (IBVS 662, 1972) preliminary periods were determined for seven of the variables. Light curves are shown in Figure 1. Because there were so few observations from which to determine the periods it is possible that the periods given here may later require adjustments. The value P_ab determined from the six ab-type variables is 0.569 days which would place the cluster in the Oosterhoff type I category and since the ratio n_c/n_ab as determined by Bartolini et al. seems to be small, NGC 1261 seems to be an AI type globular cluster using the classification of Castellani et al. (Aph.Space Sc. 9, 418, 1970). The authors plan to take additional plates of this cluster which they hope will verify these periods and allow the determination of periods for the other variables in the cluster. They would like to express their gratitude to Mr. Harris for the loan of his plates and to Dr. D. A. MacRae for allowing us to use the University of Toronto telescope at Las Campanas. We also wish to thank the National Research Council of Canada for its support of this program. [FIGURE 1a] [FIGURE 1b] [FIGURE 1c] Table I Hel. J.D. 2441000 1 2 3 4 5 6 7 8 207.851 17.6 16.70 17.1 : - - 16.25 16.55 17.05 209.787 17.0 17.05 16.42 - - 17.32 17.3 17.15 299.543 17.24 16.90 16.38 16.16 16.1 17.40 - 17.70 300.550 17.17 16.48 16.30 15.5 16.1 17.12 16.70 17.4 301.551 17.32 15.98 16.38 15.18 16.6 16.58 16.76 17.4 302.543 17.5 : 17.5 : 16.1 15.6 16.25 17.8 : 17.3 : 17.3 : 304.543 17.3 16.98 16.42 15.4 16.22 17.4 17.07 15.95 305.545 17.4 16.72 16.5 15.30 16.10 16.80 16.70 17.8 625.852 17.6 : 17.2 : 16.0 : 16.0 : 16.2 : 16.2 16.4 : 15.8 : 626.796 17.3 16.02 15.72 16.4 15.44 17.3 16.67 17.4 627.694 17.22 17.08 16.58 16.5 16.5 : 17.16 17.4 17.5 627.723 17.6 17.18 16.60 16.21 15.96 16.91 17.00 17.44 Hel. J.D. 9 10 11 12 13 14 15 2441000 207.851 17.25 17.45 16.70 17.6 16.87 17.35 14.84 209.787 16.48 17.6 17.02 17.50 17.30 16.22 15.1 299.543 16.38 17.40 17.30 16.40 17.21 17.21 15.38 300.550 16.92 17.23 16.72 17.4 17.15 16.50 15.32 301.551 16.20 16.38 17.4 17.04 17.21 17.38 15.35 302.543 16.5 17.9 : 17.2 : 17.9 : 17.3 : 17.3 : 15.4 304.543 16.09 16.73 16.80 16.77 16.80 16.36 15.48 305.545 16.85 16.59 17.3 17.7 16.80 17.7 15.30 625.852 16.4 : 16.2 : 17.4 : 17.5 : 16.6 : 17.2 : 15.43 626.796 16.66 17.3 17.6 16.93 16.42 17.4 15.44 627.694 16.50 16.48 16.17 17.35 17.1 16.38 15.45 627.723 16.66 16.33 16.80 17.56 17.20 16.30 15.41 A. WEHLAU, L. DAVIS S. DEMERS Department of Astronomy Institute of Astronomy University of Western Ontario Laurentian University London, Canada. Sudbury, Canada.