COMMISSION 27 OF THE I. A. U. INFORMATION BULLETIN ON VARIABLE STARS NUMBER 485 Konkoly Observatory Budapest 1970 November 7 PHOTOELECTRIC OBSERVATIONS OF EV Lac DURING INTERNATIONAL CAMPAIGN 23 AUGUST - 9 SEPTEMBER 1970 The results of photoelectric observations of the flare star EV Lac made at the Crimean Astrophysical Observatory during the International Campaign 23 August- 9 September 1970 are given. The observations were made in the photometric system B using the 64-cm meniscus telescope. The time intervals covered with observations are given in Table I. Table II. contains the characteristics of the flares observed. The light curves are given on Figures. [FIGURE 1] [FIGURE 2] [FIGURE 3] Table I. Date, 1970 Coverage (U.T.) Aug. 23. 19 51-20 44, 20 45-21 02 24. 18 20-18 29, 20 10-20 19, 20 20-20 23, 20 28-21 00, 21 01-21 33, 21 34-21 55, 22 01-22 41, 22 42-22 58, 23 01-23 06, 23 55-24 02 27 21 55-22 33, 22 37-22 53, 22 55-23 08, 23 10-23 56, 23 57-24 00 28 00 00-00 22, 00 23-00 50, 00 51-01 16, 01 17-01 30, 18 55-19 32, 19 33-20 03, 20 04-20 34, 20 35-21 05, 21 06-21 37, 21 38-22 16, 22 17-22 52, 22 53-23 23, 23 24-24 00 29 00 00-00 30, 00 31-01 03, 01 04-01 38, 18 16-18 49, 18 51-19 04, 19 06-19 28, 19 34-20 15, 20 19-20 39, 20 50-21 03, 21 16-21 22, 21 28-21 57, 22 03-23 30 30 18 05-18 14, 18 16-18 26, 18 27-19 56, 19 57-21 49, 21 55-22 20, 22 21-22 42, 22 43-24 00 31 00 00-00 16, 00 18-01 15, 18 03-18 13, 18 14-18 38, 18 39-18 47, 18 48-19 10, 19 13-21 39, 21 45-23 48, 23 54-24 00 Sept. 1 00 00-00 17, 00 19-01 20, 19 39-19 52, 20 45-21 13, 21 14-21 27, 21 32-23 08 2 18 00-18 07, 19 00-19 23, 19 33-19 42, 19 47-20 06, 20 07-20 42, 20 46-21 53, 22 01-23 23, 23 33-24 00 3 00 02-01 30, 17 48-19 09, 19 15-19 33, 19 53-20 01, 20 07-20 30, 20 34-20 41, 21 40-22 39, 22 49-23 03 4 18 15-18 47, 18 48-19 30, 22 13-24 00 5 00 00-00 08, 00 09-01 30 8 17 30-17 44, 17 47-18 01, 18 04-18 29, 18 30-19 00, 19 04-19 26, 19 28-20 00, 20 02-20 29, 20 40-20 58, 21 03-21 32, 21 33-22 18, 22 22-24 00 9 00 00-01 30, 17 27-17 35, 17 36-17 56, 17 57-18 20, 18 31-18 44, 18 54-19 03, 19 05-19 33, 19 35-20 00, 20 02-20 51, 21 03-21 52 Table II Date U.T. Durations P Air 1970 of flare before and Delta mB sigma/I_0 minutes mass maximum after max., M(z) minutes tb ta Aug.24 20h11.4m 0.2 0.4 0.12 0.02 0.03 1.09 24 21 46.0 1.3 7 0.34 0.02 0.91 1.04 24 22 33.1 0.7 5 0.22 0.02 0.44 1.00 27 22 24.6 0.4 2.5 0.28 0.03 0.18 1.01 29 19 52.3 0.2 0.8 0.09 0.02 0.02 1.08 30 18 39.0 1.2 2.5 0.29 0.02 0.40 1.16 30 19 43.8 0.5 8.2 0.36 0.03 1.06 1.06 30 23 00.3 0.5 0.5 0.05 0.02 0.02 1.02 Sept.1 00 14.9 0.7 1.3 0.10 0.02 0.09 1.10 1 21 25.0 - - 0.4: - - 1.00 2 23 30 - >25 > 0.3 0.02 >24 1.05 3 00 27.5 0.5 1.0 0.13 0.02 0.06 1.14 5 00 04.2 0.5 1.2 0.19 0.02 0.07 1.12 5 00 35.7 0.2 0.5 0.05 0.02 0.02 1.19 8 18 44.5 0.6 1.5 0.13 0.02 0.05 1.04 8 23 22.0 0.1 1.5 0.08 0.02 0.03 1.01 9 18 25 - >19 > 0.3 0.03 >1.9 1.19 9 20 49.5 1.0 2.5 0.23 0.03 0.25 1.13 9 21 40.2 1.6 7 0.07 0.02 0.29 1.01 P.F. CHUGAINOV N.I. SHAKHOVSKAYA Crimean Astrophysical Observatory K.L. MASLENNIKOV Leningrad State University