COMMISSION 27 OF THE I. A. U.
       INFORMATION BULLETIN ON VARIABLE STARS
                    NUMBER 461


                             Konkoly Observatory
                             Budapest
                             1970 August 28

  COOPERATIVE OBSERVATIONS OF THE FLARE STAR V 1216 Sgr

    According to the observing schedule prepared by the Working
Group on Flare Stars (Andrews and Chugainov, 1969), the star V 1216
Sgr was observed at the Catania Astrophysical Observatory from June 26
to July 10. A photometer equipped with an EMI 6256 photomultiplier
(spectral response S 13) and the Schott filters combination BG 12/1 +
+GG13/2 were used. The photometer was attached to the 91 cm Cassegrain 
telescope.
    In Table 1 the detailed coverage and in Table 2 the characteristics 
of the observed flares are presented.
    Some observations made outside the suggested period are also
included.
    The accompanying figure shows the light curves of the observed
flares, three of which are uncertain.
    R. Barbagallo and F. Spinella have collaborated in the observations.
    
    August 15th, 1970           
                                R. COSTA
                                S. CRISTALDI
                                M. RODONO
                          Catania Astrophysical
                           Observatory, Italy
Reference
Andrews, A. D., Chugainov, P. F. 1969, Comm.27. IAU, 
                           Inf. Bull. Var. Stars, No. 416




                        Table 1.
                                                                  ----------
   m  d         Coverage (U.T.)                       TC          m_lim -m_0

1970
May   9 02h17m-02h35m;0237-0242.                    0^h32^m       +4.22
June 27 2315-0400;
     28 0000-0044; 0046-00556; 0102-0126.           2 03           4.1
     28 2131-2158;
     29 0038-0042; 0049-0219.                       2 01           3.5
     29 2200-2218; 2222-2400; 
     30 0000-0005; 0025-0032; 0034-0124; 0126-0208. 3 40           3.9
     30 2202-2336; 2340-2400;
July  1 0000-0003; 0005-0100; 0103-0125; 0127-0210. 3 57           3.7
      1 2202-2220; 2224-2334; 2336-2349; 2354-2400;
      2 0000-0020; 0030-0053; 0126-0150; 0153-0200; 
        0203-0213.                                  3 10           3.8
      2 2053-2123; 2130-2344;
      3 0017-0207;                                  4 34           3.7
      3 2138-2203; 2206-2217; 2220-2236;
        2239-2308; 2318-2334;
      4 0011-0048; 0051-0200.                       3 23           3.7
      4 2301-2317; 2322-2335; 23337-2348; 2353-2400;
      5 0000-0056; 0114-0118.                       1 47           3.8
      5 2137-2257; 2314-2341; 2343-2348;
      6 0004-0058                                   2 46           4.0
      6 2215-2236; 2238-2315; 2320-2324;
        2330-2334; 2338-2346; 2349-2351; 2353-2400; 2 26           3.6
      7 0000-0029; 0114-0148.
      7 2121-2230; 2249-2322; 2330-2340; 2345-2400;
      8 0000-0002; 0005-0009; 0017-0050;
        0052-0104; 0149-0211.                       3 20           3.5
      8 2112-2345;
      9 0005-0009; 0011-0115; 0119-0128; 0155-0200. 3 55           3.7
      9 2020-2034; 2258-2345; 2347-2356;
     10 0000-0012; 0015-0021; 0044-0053; 0059-0107;
        0109-0119; 0121-0130; 0133-0210.            4 41           3.8
     10 2116-2220; 2224-2230; 2331-2322.            1 11           3.1
     12 2308-2400;
     13 0000-0012; 0031-0129; 0131-0139; 0143-0224. 1 59           3.0
     16 2006-2212.                                  2 06           3.0
     20 2052-2120; 2122-2138; 2139-2154; 2156-2209;
        2211-2216; 2218-2232.                       1 31           3.0
     21 2018-2120; 2123-2211; 2215-2258; 2300-2314;
        2316-2400.                                  3 31           3.1


m = month; d = day; TC = total coverage per night;

m_lim - m_0 = -2.5 log (3 sigma / I_0), where sigma represents the standard 
deviation of the random noise fluctuation for a night, and I_0
represents the mean intensity of the quiet star during the same night.


                         [FIGURE 1]

                        Table 2.

no        t_max      d_b   d_a   m_lim-m_0  (m_f-m_0)_max   P      M    a  b


    1970

1 May   9, 02h17.8m  0.3m  1.7m   +4.22     +1.62          0.11  2.118  -  2
2 June 30, 22 14.1   0.3   4.9    +3.94     +2.66          0.11  2.214  1  1
3 July  1, 22 44.0   0.2   6.7    +3.84     +1.29          0.22  2.137  -  4
4 July  2, 00 56.9   0.2   1.2    +3.74     +1.30          0.14  2.512  -  4
5 July  7, 00 05.5   0.2   0.9    +3.75     +2.60          0.04  2.288  1  1
6 July  9, 22 01.2   0.5   5.3    +4.06     +2.50          0.14  2.143  4  0
7 July  9, 22 11.8   0.1   0.2    +4.06     +2.83          0.01  2.122  1  0
8 July  9, 23 31.4   0.2   0.3    +3.68     +1.86          0.03  2.190  -  0
9 July 12, 23 42.6   0.3   2.6    +3.34     +0.95          0.24  2.292  2  0 

no. = order number; t_max = date and U.T. at maximum of the flare;
d_b = duration of the flare before maximum; d_a = duration of the flare
after maximum including whatever post-maximum activity; m_lim - m_0 =
-2.5 log (3 sigma / I_0) where sigma and I_0 indicate the standard noise 
fluctuation and the mean intensity of the quiet star near the observed flare,
respectively; (m_f - m_0)_max = -2.5 log[(I_0+f - I_0)/I_0]_max, where I_0+f is
the intensity deflection due to the quiet star (I_0) plus that of flare (I_f)
at maximum; P= Integral ( I_0+f - I_0)/I_0 dt, integrated intensity (in 
minutes); M = air masses to sea level; a = flare feature: 1=uncertain, 2=double,
3 = multiple, 4 = complex structure; b = sky condition with the following
standard: 0 = very clear, 1 = clear, 2 = with some cirrus, 3 = extended cirrus,
4 = with some clouds, 5 = cloudy.