COMMISSION 27 OF THE I. A. U.
         INFORMATION BULLETIN ON VARIABLE STARS
                      NUMBER 685

                                           Konkoly Observatory
                                           Budapest
                                           1972 June 20


          PHOTOELECTRIC OBSERVATIONS OF AD Leo


Photoelectric monitoring of the star AD Leo was carried out in the time
interval 10 - 22 February 1972 (IBVS 605). The observations were effectuated on
the 40 cm reflector of the Byurakan Observatory with a FJY-79
photomultiplier and a corresponding B filter. The pulse counting technique
with continuous registration on the recorder chart was applied.

The observational data (IBVS 488) are presented in Table I.

The light curves of the observed flares are given in the figures. The ordinate
is given in the units of Xf/Xs.

                         [FIGURE 1]

Table I


Date  Coverage   UT_max     t_b   t_a    X_fM    sigma   P    F(z)    Notes
UT      UT                               ----    -----
                                         _       _
                                         X_s     X_s

Feb.
1972
10    1730-1800    h m                           0.010
      1802-2300  18h21.6m    0.87  10.8  0.61    0.010    1.09  1.57
                 22 17.8     1.5    7.6  0.77    0.010    3.5   1.07

11    1800-1912                                  0.012
      1920-1930                                  0.012
      2015-2035                                  0.012
      2104-2330                                  0.012
      2332-2400                                  0.012

12    0000-0100                                  0.012
      1923-2052                                  0.023

13    2100-2400                                  0.015

14    0000-0200                                  0.014

15    1733-1837                                  0.015
      1933-2056  20 39.8      0.5   1.5   0.08   0.015   0.044   1.09
      2205-2214                                  0.015

19    2030-2400                                  0.035                   1

20    0000-0031                                  0.025                   1
      1809-2208  21 36.3     0.15   14.5  0.10   0.012   0.65    1.08
      2212-2253                                  0.012
      2256-2308                                  0.012
      2348-2400                                  0.012

21    0000-0032                                  0.012
      1744-1855  18 12.2     0.20    6.0  0.22   0.014   0.29    1.40
      1948-2037                                  0.014
      2045-2400                                  0.014

22    0000-0024                                  0.033           1
      1800-2005                                  0.032           1
      2104-2200                                  0.011
      2201-2900                                  0.010

23    0000-0130                                  0.008

Total coverage 2495 minutes.

Notes:

1.-Poor weather conditions. Clouds.


V.S. OSKANIAN
Byurakan Observatory
Armenia, USSR.