COMMISSION 27 OF THE I. A. U.
        INFORMATION BULLETIN ON VARIABLE STARS
                     NUMBER 512

                       		        Konkoly Observatory
                        		Budapest
                        		1971 January 28


          A LONG-PERIOD ECLIPSING BINARY

     MMO 705 at 18h 45m.0, -8d 35' (1900) was observed
on 149 24-inch Bruce plates by V.M. Swain and on 47 48-inch
Palomar Schmidt plates by L.J. Robinson. These yielded only
three minima, indicating an eclipsing star of long period.
Several hundred Harvard patrol plates were then examined to
establish the period. All minima are given in the table, 
together with O-C's computed from these elements:

     Hel. JD = 2,427,805.94 + 31.9384d E.

                Photographic magnitudes of the
                comparison stars identified in Fig. 1
                (4' by 3 1/2' in size) were derived
                from photoelectric standards:
                A, 12.14; B, 13.03; C, 13.91;
 [FIGURE 1]  
                D, 14.23; E, 15.01; F, 15.60.
                Means of magnitude estimates are
                plotted in Fig. 2, the large dots
                representing more than five observations.
                In the phase interval 0.57-
                0.66, some individual estimates are
                also included.


                 [FIGURE 2]


--------------------------------------------------------------------------
   JD         E           O-C  Camera        JD         E       O-C Camera
--------------------------------------------------------------------------
2420304.77   -235       +0.35   MC      2429849.64     + 64   -0.39   BM
25889.53     - 80       -0.11   MC,RH     30521.56     + 85   -0.14   RB
26177.49     - 51       +0.41   MF        30553.32     + 86   +0.68   RB
28208.43     - 50       -0.59   MF        30872.62     + 96   +0.59   A
26240.35     - 49       -0.61   MF        30999.26     +100   -0.52   RB
26815.60     - 31       -0.25   MF,RB     31670.40     +121   -0.09   RB
27933.82     + 4        +0.13   RH        32021.57     +132   -0.24   RB
28700.74     + 28       +0.52   BM        32054.24     +133   +0.49   RB
28731.59     + 29       -0.58   A         32404.66     +144   -0.41   RH
29434.57     + 51       -0.23   RB        33938.28     +192   +0.17   RB
29466.41     + 52       -0.33   RB        35279.86     +234   +0.33   PS
29818.68     + 63       +0.62   BM        
--------------------------------------------------------------------------

A 24-inch Bruce, BM 3-inch Ross-Lundin, RB 3-inch Ross-
Fecker, RH 3-inch Ross-Fecker, MC 16-inch Metcalf,
MF 10-inch Metcalf,  PS 48-inch Palomar Schmidt.

     The photographic range of MMO 705 was found to be
13.3-15.6. The eclipses last about 3 1/4 days with about 1 1/2
days of constant light at mid-minimum. These durations are
somewhat uncertain due to poor distribution in phase of the
plates.
     For the length of its period, this star is notable
for the long duration of primary eclipse and of mid-minimum.



                         L.J. ROBINSON
                          M. HARWOOD
                       Cambridge, Mass, USA