COMMISSION 27 OF THE I. A. U.
        INFORMATION BULLETIN ON VARIABLE STARS
                     NUMBER 657

                                      Konkoly Observatory
                                      Budapest
                                      1972 April 10


             THE ECLIPSING BINARY BD +16deg516



We have observed the eclipsing binary, BD +16deg516, of which one component
is a white dwarf, during the 1970-71 and 1971-72 seasons, and present here
our solution for the heliocentric light elements:

Min.=JD 2440896.715678+0.52118372d * E
                  +-26        +-5 (s.e.)

These elements are based upon 16 primary minima for which both the beginning
and the end of each eclipse were observed. The observations were made with the
40 cm reflector at the Morgan-Monroe station of the Goethe Link Observatory
near Bloomington, Indiana, and with the similar telescope at the Joseph R.
Grundy Observatory in Lancaster, Pennsylvania. The star was always observed
through a filter similar to the U filter of Johnson's UBV system; the eclipse
phases were measured on stripchart recordings with time marks obtained from
radio time signals. We define the time of minimum as 1/2(t_1+t_2), where t_1,
is that time Between first and second contact when the brightness is midway
between the brightnesses before and after the partial phase; similarly t_2 is
the time of mid-brightness occuring between third and fourth contact. We
estimate that the times of minimum determined in this way are accurate to 5s
for most minima. The time interval t_1-t_2 appears to be practically constant
at 48m08s +-7s. On the other hand, the duration and slope of the partial
phases definitely seem to be variable; we expect to study this variation
further.

As can be seen in the following table, the residuals are mostly consistent with
the accuracy estimate quoted above, and we conclude that no period changes are
indicated by the present material. We note, however, that these elements
disagree somewhat with those of Nelson and Young (PASP 82, 699, 1970); the
discrepancy amounts to 51s at their zero epoch.

  E   O-C   Remarks     E    O-C   Remarks
      sec                    sec
  0    2     B         689    -4     B
  4    0     B         752     0     L
 21    2     B         769   -14     L
 29   -4     B         773     6     L
228   -3     B         783     8     B 1
253    6     B         817     2     L
276  -10     B 1       823     2     L
278   -1     B 1       842   -10     L 1
599    9     B         888     3     L
614   13     B 1       894     2     B 1
618    2     B         917    -3     B 1
645    1     B

Remarks:

B observed at Bloomington
L observed at Lancaster

1 only one partial phase observed, minimum time calculated assuming
  t_2-t_1=48m08s. Not included in the solution for the elements.

We thank Dr. Martin S. Burkhead and Mr. Anthony J. Distasio for assistance
in obtaining several of the minima.


LEIF E. ANDERSON
Goethe Link Observatory
Indiana University
Bloomington, Indiana 47401
U. S. A.

MICHAEL A. SEEDS
Joseph R. Grundy Observatory
Franklin and Marshall College
Lancaster, Pennsylvania 17604
U. S. A.

Goethe Link Publication No. 136