COMMISSION 27 OF THE I. A. U.
         INFORMATION BULLETIN ON VARIABLE STARS
                        Number 943

                                   Konkoly Observatory
                                   Budapest
                                   1974 November 15


      MULTI-COLOUR PHOTOMETRY OF V1216 SAGITTARII

The flare star V1216 Sgr was observed photoelectrically using the
24" Cassegrain reflector of the Ruhr-University of Bochum at La Silla
(ESO), Chile. The photometer used is a one channel type with computer
controlled filter switching. Since the switching time lowered the 
detection efficiency, the instrument has been operated just in two 
colours. In practice this is accomplished by two subsequent observations,
the first measurement is done with an U-filter followed by an observation 
either in B, or V, or H_{beta} respectively.
Once each five seconds data from the blue-sensitive photomultiplier
are stored in the computer's memory which has been adjusted of 
retaining up to 45 minutes of data. After this time the data are 
subject to be printed when the maximum of the intensity shows a 
departure from the steady level of greater than 0.1 magnitudes.
The transformation from the instrumental to standard UBV-system has
been determined by differential measurements.
The mean standard magnitude of one recommended comparison star of
Andrews (1968, IBVS No. 265) has been used. This star with the code
letter d has nearly the same colour as V 1216 Sgr, thus extinction
does not affect seriously the amount of

               m_{Sgr} - m_d,

whereas the difference of the differences
       Delta{m} = (m_{Sgr}-m_d)_{UBV-Standard}- (m_{Sgr}- m_d)_{Instrument}
contains the transformation to the standard system.

Thus, we have
                                            U      B       V
Andrews (IBVS No.265,1968) m_{Sgr}-m_d =   0.2    0.2    -0.15
this report                            =   0.3   -0.2    -0.06

Except in B the deviation from the standard system is equal or less
than 0m.1.
The result that may be drawn can be summarized as
V 1216 Sgr               U     B     V
                   m = 12.8  12.1  10.1

Error rate : +- 0m.1


Below the peak magnitudes of the total number of events are listed
and presented along with four light curves (Fig. 1 and Fig. 2) of the
most significant events.

                          Table
                    Flares of V1216 Sgr

    Date     U.T.       U          B       H_{beta}      V
June,1974    Max     Delta{m}   Delta{m}   Delta{m}   Delta{m}
    14.     3h21m    >1                                <0.1
    15.     2 57      1.45                             <0.1
    17.     4 08      1.34       0.13
    21.     2 36      0.67       0.09
            5 23      1.07       0.11
    22.     2 55      1.43       0.17
    23.     4 17      1.20                  0.18
    28.     7 32      1.77                  0.89

Total Observing Time : 54h



                                 G. FEIX
                            Ruhr - Universitat
                            Bochum, Astron. Inst.
                            463 Bochum, FRG


                       [FIGURE 1]
                       [FIGURE 2]