COMMISSION 27 OF THE I.A.U.
       INFORMATION BULLETIN ON VARIABLE STARS
                    NUMBER 198


                                       Konkoly Observatory
                                       Budapest
                                       24 April 1967


Correction to IBVS No. 193. Prof. Tempesti cabled: The announcement 
of the variability of the star BD +18d2304 is erroneous,
the variable concerned is identical with XY Leo. Teramo Observatory.


                 PHOTOELECTRIC MINIMA FOR SW LAC

Since a long time it is known that this eclipsing variable has
a variable period. Photoelectric observations, made at the Nurnberg
observatory in the years 1963 till 1966, show large, increasing positive 
O-C's against the elements given in GCVS (I) and SAC 38 (II), 
respectively:

Min: JD2423372.7974+0.32071483day x E+ 0.023day x sin (0.0053deg x E -76deg) (I)
                                    - 0.0022day x sin (0.0086deg x E -60deg)

Min: JD 2435667.474 + 0.320722day x E                                (II)

From five photoelectric minima I derived the new elements:

Min: JD 2438235.518 + 0.32072829day x E                              (III)

The minima obtained at the Nurnberg Observatory are given in
the following Table together with the O-C's computed with formulas (I)
to (III).

Minima           O-C (I)   O-C (II)   O-C (III)

2438235.518     -0.011day  +0.023day   0.000day
    708.271     +0.012     +0.032      0.000
    709.393(m)  +0.011     +0.032     -0.001
  39059.468     +0.027     +0.038     -0.001
    443.381     +0.047     +0.047      0.000

(m) = secondary minimum.


Nurnberg Observatory,
                                     E. POHL

                            85 Nurnberg, Lutzowstr. 10
                                Western Germany