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

                    NUMBER  422

                           Konkoly Observatory
                           Budapest
                           1970 March 4


    ON FOUR VARIABLE STARS IN THE GLOBULAR CLUSTER M 2

    Four variable stars  (V18, 19, 20 and 21) were
discovered in 1967 by R.Margoni and R.Stagni (1)  and preliminarily 
investigated  by myself (2). According to 160
estimates on Moscow plates obtained in 1960,1963,1968 and
1969 and about 170  estimates in B and 90 in V by R.Margoni
and R.Stagni (3) (1965-1968)  the following  results were
established:

V18 Very interesting  star with strong variable period and
    light curve. The following  four systems of linear
    elements were obtained:
    I. Before JD 2437450         t0 =2437162.392+0d36201.E
    II. From 2437450 to 39250    t0=2438282,1?8+0.36189.E
    III. From 2439250 to 39950   t0=2439351.255+0.36205.E
    IV. From 2439950 to          t0=2440088.467+0.36226.E
                   
V19 Two systems of  linear elements represent all observations 
    very well.
    I. Before JD 2438850         t0=2437162.373+0d.319299.E                              
    II. After JD 2438850         t0=2439089.384+0d.319403.E
    
V20 The following linear elements represent satisfactorily
    all available observations from JD 2437087 to 2440478:
		t0 =  2437162.281 + 0d.2883224.E.

V21 Two systems of linear elements were determined:
    I. Before JD 2439700         t0 = 2437162.376+0d.712154.E
    II. After JD 2439700	 t0 = 2439789.516+0d.712178.E
                         
    The symbol t0  denotes  the moment of the median
    magnitude on the ascending branch of the light curve.
  
    References:
    1. R.Margoni, R.Stagni, IBVS 239, Dec.9, 1967
    2. B.Kukarkin, IBVS 253, Febr.8, 1968 and 254, Febr.16, 1968.
    3. R.Margoni, R.Stagni, Asiago Contr. 213, 1969.

    Crimean Station of Sternberg Astronomical Institut
    February 1970
                                             B.KUKARKIN