COMMISSION 27 OF THE I. A. U.
        INFORMATION BULLETIN ON VARIABLE STARS
                     NUMBER 547

                               Konkoly Observatory
                               Budapest
                               1971 May 7


  UBV PHOTOMETRY OF THE COMPOSITE STAR DELTA SAGITTAE

      A few differential UBV observations were made of
the composite star Delta Sge (M2II? + B?) in an attempt to
detect an atmospheric eclipse which, as Koch (1969) pointed
out, might have occurred at the end of the calendar year
1969.
      The comparison star was Zeta Sge ABC, and all three
components were included in the diaphragm. The differential
magnitudes were corrected for differential extinction, both
principal and second-order, and transformed to the UBV
system. The telescope was a 24-inch reflector and a refrigerated 
1P21 photomultiplier was used. The observations are
listed in Table I, where the last three columns are the
differential UBV magnitudes in the sense variable minus
comparison.




                     TABLE I
            Differential UBV Observations
            (Delta Sge minus Zeta Sge ABC)
--------------------------------------------------------------------
Date               JD hel.           DeltaV      DeltaB       DeltaU
                   2,440,000+
--------------------------------------------------------------------
26-27   Sept. 1969   491.60          -1.19m      +0.13m       +0.99m
                        .61          -1.19       +0.13        +0.98
                        .62          -1.20       +0.13        +0.98
28-29   Sept.1969    493.57          -1.19       +0.13        +0.99
                        .58          -1.19       +0.13        +1.00
1-2     Dec.1969     557.53          -1.23       +0.13        +1.04
                        .54          -1.22       +0.12        +0.98
                        .55          -1.21       +0.10        +1.02
                        .56          -1.22       +0.13        +1.02
20-21   Feb.1970     638.96          -1.19       +0.15        +1.02
                        .97          -1.18       +0.16        +1.03
                        .98          -1.18        -            -
--------------------------------------------------------------------




      There is no indication that Delta Sge changed
significantly in brightness in any color, but these few
observations should perhaps be combined with any others
which were obtained during the 1969-70 season before it is
decided whether or not an atmospheric eclipse did occur.

April 26, 1971


                        DOUGLAS S. HALL
                       Dyer Observatory
                      Vanderbilt University
                   Nashville, Tennessee 37203
                           U.S.A.



REFERENCES:

Koch, R.H. 1969, I.A.U. Central Bureau for Telegrams, Circ.
   No. 2165.