COMMISSION 27 OF THE I. A. U.
         INFORMATION BULLETIN ON VARIABLE STARS
                      NUMBER 333


                                  Konkoly Observatory
                                  Budapest
                                  1969 March 5


        PHOTOELECTRIC OBSERVATIONS OF AD LEO,
  DURING THE 1969, 10-24 FEBRUARY INTERNATIONAL PATROL


      The photoelectric observations of the flare star
AD Leo (BD +20deg2465, m_V=9.4, m_B=10.9) carried out at Catania
Observatory during the planned period are reported.
      Two cassegrain reflectors of 91 cm and 30 cm apertures,
the former working at lambda_eq = 4300 A and the latter at
lambda_eq = 5150 A, were employed.
      The characteristics of our observations and the 
obtained data are given in Tables I and II.
      Few measurements of the comparison star BD +20deg2475
(m_V=8.91, m_B=9.16), which was occasionally checked with
BD +21deg2193 (m_V=7.73, m_B=9.07), were performed.
      Taking into account the overlapping coverages of
the two telescopes, we obtained a combined total coverage
(CTC) of 25.47 hours. The four flares observed during the
latter period are drawn in Fig. 1.




Catania Astrophysical Observatory
February 26, 1969
                             S. CRISTALDI
                             M. NARBONE
                             M. RODONO

		   Tab. 1

              Detailed Coverage     
N Feb.   Tl L                                                TC    Deltam_lim   CTC
08-09    91 B 01h31m-0255; 0258-0327; 0331-0452.           194m     -0.015      194m
13-14    91 B 2008-2142; 2147-2225.                        132      -0.035      132
14-15    91 B 1902-1948.                                    46      -0.034
         30 V 1916-1927; 1932-1948.                         27      -0.025       46
15-16    91 B 2026-2035; 2037-2205; 2212-2307; 2313-008;
              0013-0044.                                   239      -0.020
         30 V 1945-2032; 2053-2231; 2238-2330; 2339-2349.  177      -0.025      272
17-18    91 B 1938-1957; 1959-2035; 2041-2056; 2104-2134;
              2136-2147; 2153-2210; 2213-0040; 0048-0139;
              0142-0151; 0201-0220; 0224-0349.             442      -0.030      442
21-22    91 B 1911-2036; 2038-2134; 2141-0124; 0128-0300,  442      -0.018      442
                                                                             

                                                                             Tab.II
                   Observed Flares
                                                            
N       CTC  Nr Tl  L   t_b      t_max    t_e    Deltam_lim    (I_0+F-I_0/I_0)_max   P
Feb.
13-14   132m 1  91  B  21h26.9m 21h29.1m   ?      -0.035             0.147           ? 
14-15    46  2  91  B  19 08.0  19 08.8  19h10.6m -0.034             0.126          0m188
             3  91  B  19 10.6  19 12.2  19 17.0  -0.034             0.149          0.502
15-16   272  4  91  B  20 54.4  20 55.2  21 10.0  -0.020             0.222          0.574
             5  91  B  23 25.4  23 25.65 23 31.0  -0.020             0.142          0.092


                       [FIGURE 1]