COMMISSION 27 OF THE I. A. U.
          INFORMATION BULLETIN ON VARIABLE STARS
                       NUMBER 836

                          	        Konkoly Observatory
                                	Budapest
                                	1973 October 20

  PHOTOELECTRIC OBSERVATIONS OF EV Lac DURING THE 1973 AUGUST 22 - 
               SEPTEMBER 4 INTERNATIONAL PATROL


   According to the observation schedule proposed by the I.A.U.
Working Group on flare stars (Chugainov, IBVS 744, 1972) EV Lac
has been observed at the Catania Astrophysical Observatory using
   i) a synchronous UBV photometer fed by a 61 cm universal time
reflector, or
   ii) three similar one-channel photometers fed by a 91 cm
Cassegrain reflector and two 30 cm cassegrain reflectors, 
respectively. The 30 cm reflectors were fixed on a common mounting.

              		Table 1. Detailed Coverage

Date    Tel. Light   		Coverage (U.T.)                    Total     __________
1973                                                   		  coverage   3sigma/I_o
Aug.
23      91 	u              00h23m-0045                           22         .04
        91/30/
        /30 	u/b/v          0045-0134,0148-0247,0254-0303;  	    117         .04/06/05
24      91 	u              0027-0134.                            67         .04
       91/30/
        /30 	u/b/v          0134-0305;                            91         .04/07/02
24-25  61 	u/b/v          2158-2301,2307-2347.            	    103         .17/03/02
       30/30 	b/v            0010-0114.                            64         .04/03
       91/30/
        /30 	u/b/v          0114-0139.                            25        .08/04/03
25-26   61 	u/b/v          2110-2228,2238-2324,2333-2338.       129        .13/03/02
26-27   61 	u/b/v          2104-2139,2213-2245,2250-2354.       131        .16/03/03
        30/30 	b/v            0041-0050,0053-0259.            	    135        .03/03
29-30   61 	u/b/v          2109-2152,2222-2324.            	    105        .15/03/03
        30/30 	b/v            2333-2400,0000-0122.            	    109        .05/03
30-31   91 	u              2152-2249.                            57        .08
        91/30/
         /30 	u/b/v          2254-2302,2306-2333,2357-2400,
			       0000-0315.                           233        .08/05/04
Aug. 31-
Sep.1    61 	u/b/v          2109-2123.                            14        .16/03/03
Sep.
3-4      61 	u/b/v          2101-2202.                            61         .14/03/03
        30/30 	b/v            2145-2216,2239-2251.            	     43         .07/04
        91/30/
        /30 	u/b/v          2254-2338,0056-0218,0221-0309. 	    174         .12/07/04

   D.C. amplifiers and strip chart records with a time-constant
of 1 sec.f.s. were used.
   Some preliminary results of the observations are here presented.
   Table 1 gives the detailed coverage in U.T. Patrol interruption
longer than one minute are noted. During 28.0 hours of effective 
coverage 4 flares were observed. Some characteristics of these flares
are given in Table 2. Their light curves, as relative intensities
in the instrumental photometric system versus U.T. are shown in the
accompanying figures. The error bars indicate the maximum noise
fluctuations of the recordings.
   The explanation of symbols and further details both on the 
observing equipment and on the reduction procedure can be found in
Cristaldi and Rodono Astr.Astrophys.Suppl. 10, 47. 1973.
   R. Barbagallo, A. Cali and C. Lo Presti have cooperated in this
work.

             Table 2
No. Tel. Light  tmax(U.T.) J.D.hel.  d_b  d_a  3sigma/I_or(I_f/I_o)max 	Energy          Air
                1973 	   2441...        			       p     erg        mass
        	August 23					
1   91   u  							  		
             00 27.9 	   917.5226  0.4  5.1     0.04     5.09      5.80  1.83x10^31	0.827
2   91   u   24,(0049.3)   918.5375   -  13.6     0.04    (0.40)    (1.75) 5.53x10^30 	 .841
3   91   u   30,2223.7     925.4366  0.2  8.8     0.08     1.78      1.52  4.82x10^30	 .826
             September
4   91   u   03,2256.9     929.4598  0.4  38.6    0.12    13.86     26.23             	 .817
    30   b      2256.9               0.4  18.6     .07     2.91      4.68
    30   v      2256.9               0.4   9.5     .04     0.72      0.97
         
         U                                         	  15.80     29.90  9.45x10^31
         B               				   1.89      3.03  6.68x10^31
         V                                                 0.62      0.84  4.13x10^31


Catania Astrophysical Observatory
95125 Catania, Italy



                              S. CRISTALDI
                              M. RODONO


                       [FIGURE 1]

                       [FIGURE 2]