COMMISSION 27 OF THE I. A. U.
         INFORMATION BULLETIN ON VARIABLE STARS
                      NUMBER 281

                                   Konkoly Observatory
                                   Budapest
                                   1968 June 12


     TIMES OF MINIMUM AND DURATIONS OF ECLIPSE


In the fall of 1965 several eclipsing binaries were observed photoelectrically
at Kitt Peak with a 16-inch telescope. For each binary the table lists the
duration of totality (when it was observed) and the estimated uncertainty.
Also listed for each is the O-C time of minimum, calculated from the elements
in the Finding List.

Eclipsing      O-C              d
Binary       hrs:mins+-mins   hrs:mins+-mins
U Cep        2:28+-:15         2:00+-:25
X Tri         :36+-:01          :18+-:03
ST Per      -1:33+-:02          :52+-:05
RW Tau      -2:03+-:05*         ........
RW Per        :42+-:05         2:15+-:30
TW Dra        :19+-:07*         ........
U Sge         :07+-:01         1:50+-:05
SW Cyg       1:54+-:05          ........
W Del        2:20+-:03         1:42+-:10
RT Lac pri  -3:20+-:15          :45?
       sec  -3:35+-:15          :45?
AR Lac pri    :50+-:03*         ........
       sec    :55+-:10*         ........
TW And       1:02+-:03         2:06+-:10

For the four cases marked with *, only one internal contact was observed but
the O-C was determined nevertheless by assuming a value of d from another
source. U Cep is well known to have a variable duration of totality, so the
averaging of several minima observed during October caused the relatively large
uncertainty. For RT Lac it is not certain that the eclipses are complete, so
both values should be considered approximate upper limits.


                                DOUGLAS S. HALL
                                Dyer Observatory
                                      and
                         Kitt Peak National Observatory