COMMISSION 27 OF THE I. A. U.
        INFORMATION BULLETIN ON VARIABLE STARS
                     NUMBER 439

                             Konkoly Observatory
                             Budapest
                             1970 June 5

    PHOTOELECTRIC PATROL OF THE FLARE STAR BD +13 2618

      During the period (April 15-18,1970) of cooperative
observations planned by the Working Group on Flare Stars
(Andrews and Chugainov, 1970), the flare star BD +13 2618
was observed photoelectrically at our Observatory with a
91 cm and a 30 cm cassegrain telescope feeding similar
photometers equipped with EMI 6256 photomultiplier (Spectral
response S 13). As a rule, the observations were carried out
in b light using the Shott filters combination BG 12/1
+ GG 13/2. A few measurements in v light were also made
using a GG 14/2 Shott filter.
      No flare activity was detected during the 17.2
hours of patrol of b light and the 0.5 hour of patrol of
v light. The Table overleaf contains the intervals of effective 
monitoring time and, for each night, the difference
between the limiting magnitude (m_lim) and the magnitude of
the quiet star (m_o), as defined by m_lim-m_o=-2.5*log(3*sigma/I_0),
where sigma reprsents the standard deviation of the mean random
noise fluctuation and I_o the mean intensity of the quiet
star.
      F. Spinella and V.Stancanelli have collaborated in
the observations.

                     S. CRISTALDI and M. RODONO
                     Osservatorio Astrofisico
                       Citta Universitaria
May 9th, 1970            95123 Catania



Reference:
Andrews, A.D, Chugainov, P.F., 1970, Comm. 27 IAU, 
      Inf.Bull. Var.Stars, No. 416
	
		

Date	  F  Telescope
1970	       		Coverage (U.T.)				m_lim -m_0

Apr. 19   b    91 cm	20h 19m-20h38m				+4.42m
Apr. 23   b    91	1924-1925; 1926-1932; 2015-2017;	
          v		2013-2015;				+5.61
Apr.24/25 b    91	2221-2226; 2236-2240; 2258-0032;
			0033-0047; 0055-0058; 0103-0107;
			0107-0205				+4.15
Apr.25/26 b    30	1944-2106.				+4.35
	  b    91	2306-2308; 2338-0040; 0058-0233;	
			0238-0244; 0246-0248.			+5.12
Apr.26/27 b    91	2001-2003; 2009-2104; 2115-2153;
			2156-2204; 2207-2210; 2219-2241;
			2243-2245; 2246-2336; 2346-0024;
			0027-0038; 0041-0052; 0106-0140;
			0143-0209				+6.30
           v		2003-2008; 2111-2114; 2216-2218;
			2344-2346; 0104-0107.			+5.32
Apr.27/28  b   91	2005-2007; 2063-2101; 2117-2227;
			2237-2252.				+5.00
	   v		2007-2012; 2112-2116.			+5.13
Apr.28	   b   91	2324-2341.				+3.55