COMMISSION 27 OF THE I. A. U.
            INFORMATION BULLETIN ON VARIABLE STARS
                         Number 3646   

                                                Konkoly Observatory
                                                Budapest
                                                31 July 1991

                                                HU ISSN 0374 - 0676


               NSV 13679: AS YET ONLY ONE MINIMUM


In the compilation of his first Zone Catalogue Frank Schlesinger^1 found the
star BD+49d 3511 at 21h 21m 07s +50d 17.7' (1950) lacking on one of the two
Allegheny plates on which it was to be measured.  The original Allegheny plates
are at Yale.  Besides the two on Schlesinger's program, I found a third where
the star was at the plate edge outside the region to be measured.  That plate
showed the star at maximum.  On the plate on which Schlesinger had reported the
star missing it is in fact visible, just above the plate limit, probably about
11.5 or 12th photographic magnitude.  Thus the star was normal brightness, 9.1
pg, on August 23 and September 18, 1915, but faint on September 16.

In the Yale Archives there is a copy of a letter from Schlesinger to Harlow
Shapley dated December 4, 1924, indicating that Schlesinger had asked Shapley to
check the Harvard plates of the region.  However, I find no evidence as to
whether or not such a search was actually made.  Hence, on a visit to Harvard
College Observatory, I first searched all the plates covering the region that
were taken in August and September 1915.  On none of the Harvard plates in this
interval (Table I, where A = Allegheny, H = Harvard) was the star fainter than
its normal brightness.)

          TABLE I. Observations Near Minimum, 1915

 Before minimum       Minimum           After Minimum

Aug.23 A             Sept.16 A           Sept.18H
Aug.25 H                                 Sept.19A
Aug.26 H                                 Sept.21H
Sept.9 H                                 Sept.22H
Sept.10H
Sept.11H

I then examined the star on about 200 patrol plates taken between 1898 and 1921
but found no further minima.  There are approximately a thousand more plates
available for a future visit to Harvard.  Meanwhile, can anyone at another
observatory find plates taken in the critical 1915 period, especially on
September 16, to verify the one minimum found?  On the Allegheny plate there is
no evidence that the image has been affected by any plate blemish.  From one
minimum among 200 plates examined, if the star is an eclipsing binary the
maximum duration of minimum would be approximately seven days (Sept. 11 to 18).
The maximum possible period would then be almost four years.

The Figure is a finding chart based on a Lick Atlas photograph.  Table II
identifies a number of the neighboring stars and gives their photographic
magnitudes from the AGK2 catalogue^2 (In the AGK3 the same magnitudes are
given, but with a few of the stars omitted.)


                                 [FIGURE 1]


TABLE II. NSV 13679 and Comparison Stars
            BD          pg    Sp
Var.   +49d 3511        9.3   A7
A           3513        8.4   F8
B           3516        8.9   K0
C           3514        9.4   K5
Dp          3510p      10.4   A5
Ds          3510s      10.9   -
E           3512       10.5   -



                       DORRIT HOFFLEIT
                       Department of Astronomy
                       Yale University
                       New Haven, CT 06511, U.S.A.

REFERENCES:
Schlesinger, F., 1925, Trans. Yale Univ. Obs., Vol. 4.
Schorr, R. and Kohlschutter, A., 1951, Zweiter Katalog d. Ast.
  Gesellschaft, Vol. 4.