COMMISSION 27 OF THE I. A. U.
      INFORMATION BULLETIN ON VARIABLE STARS
                   NUMBER 410

                               Konkoly Observatory
                               Budapest
                               1969 December 30


       PHOTOELECTRIC OBSERVATIONS OF EV Lac

     The photoelectric monitoring of the flare star
EV Lac in the B photometric system was carried out in september 
1969 according to the cooperative programme. The
84 cm meniscus telescope of the Crimean Astrophysical Observatory 
was used. The dates and UT of coverage are given
in Table I. Table II contains the characteristics (I) of
eight flares observed: moments of maxima (UT); durations or
the flares before and after maxima t_b and t_a (in minutes);
amplitudes of flares delta(m_B) in stellar magnitudes; standard
deviations sigma/I_o; integrated intensities P (in minutes) and
the air masses M(z). The light curves of flares in relative
intensities are given on the figures. It must be noted that
EV Lac was observed always with its optical companion.
Therefore the delta(m_B) values refer to the variation of the
combined light of both stars.

                        


                                Table 1

      Date                    UT of coverage

Sept.   4       19h07m-21h29m, 2150-2200, 2207-2323, 2339-2350,
        5       1847-1904, 1926-1931, 1934-1938,
        6       1729-1900,
        8       1723-2031, 2041-2324, 2326-2400,
        9       0000-0009, 0026-0048, 0050-0148, 0149-0157,
                0159-0200, 1905-1922,
       10       1728-1813, 1816-1900, 1904-1920, 1921-2004,
                2037-2100, 2105-2147, 2151-2311, 2328-2400,
       11       0000-0041, 0053-0137, 1723-1738, 1741-1750,
                1755-1811, 1812-1828, 1831-1919, 1921-1936,
                1939-2000, 2003-2038, 2039-2119, 2123-2231,
                2246-2339, 2341-2400,
       12       0000-0021, 0024-0410, 0142-0200, 1718-1736,
                1737-2101, 2108-2220, 2222-2330, 2357-2400,
       13       0000-0101, 0102-0200, 1739-1930, 1932-2037,
                2039-2101, 2107-2119, 2123-2400,
       14       0000-0035, 0047-0200,
       15       1703-1733, 1741-2017, 2024-2027, 2052-2102,
                2147-2211, 2218-2255,
       16       2145-2208, 2213-2237.


                                Table 2


Date and UT
of flare                t_b     t_a     m_B     sigma/I_0     P       M(z)
maximum                                                      

Sept. 10   19h16.0m     0.1     0.7     0.08    0.01         0.02    1.02
      10   19 24.8      0.3     3.9     0.19    0.01         0.20    1.01
      11   00 17.1      6.7    10.0     0.52    0.02         3.59    1.31   
      11   20 05.9      0.2     0.4     0.25    0.02         0.04    1.00
      12   22 14.7      0.7     4.7     0.26    0.01         0.21    1.06
      13   20 31.9      0.8     2.1     0.15    0.01         0.15    1.00
      14   00 20.0      0.6     1.0     0.08    0.01         0.06    1.32
      14   01 14.3      1.9    10.7     0.16    0.01         0.62    1.58


                           [FIGURE 1a] 
                           [FIGURE 1b] 
                           [FIGURE 2a] 
                           [FIGURE 2b] 


                      P.F. CHUGAINOV
                      N.I. SHAKHOVSKAYA
                 Crimean Astrophysical Observatory

[References]
(I) A.D. Andrews, P.F. Chugainov, R.E. Gershberg, V.S. Oskanjan,
   I.B.V.S., No. 326, 1969

Correction to IBVS 399: For Sept. 15 the time of maximum
                        should be read 17h01m8 (instead of
                        17h31m8).