COMMISSION 27 OF THE I. A. U.
         INFORMATION BULLETIN ON VARIABLE STARS
                     Number 2615

                                   Konkoly Observatory
                                   Budapest
                                   26 October 1984

                                   HU ISSN 0374 - 0676




           ON POSSIBLE OPTICAL COUNTERPARTS OF THE
        GAMMA BURST SOURCES GB 790 325 AND GBS 1703 +01



   GB 790 325
   The position of this source is approximately identical with that of the
small-range slowly varying M giant V669 Herculis (= 104 Herculis). Although
this coincidence might easily be purely spurious it should be mentioned
because obviously it has escaped attention so far.

   GBS 1703 + 01
   Altogether 669 Sonneberg sky patrol plates of the years 1956 to 1983 and
31 plates taken with the 17/120 cm astrographic camera in the years 1932 to
1935 were examined for eruptions in the optical region at the error box of
the burst position. The exposure times of the plates range from  30 ...60
minutes (sky patrol) to 1 ... 3 hours (astrographic camera).
   On the plate Te2 7679 of 1947 May 17.981 (middle of exposure time,
heliocentric UT) a clearly visible star-like image has been found very near the
position of the source. Just like Schaefer's well-known case of GBS 0117-29
(Nature 294, p. 722, 1981) the image differs slightly in shape from "ordinary"
stars, the latter being elongated by a small guiding error. The photographic
brightness was determined as ~~11.2m (Mt. Wilson system) by comparing with
SA 108, the threshold of the respective plate being 13.0m. On a simultaneously
taken mpv exposure (limiting magnitude ~~12.0m) no sign of any image can be
perceived at the given position. It should be noted that both Schaefer's and
our object can be explained also as being plate faults. Therefore many more
observations are needed.
This work was done under the supervision of Drs. W. Gotz and W. Wenzel
of Sonneberg Observatory.



                            M. SCHOLZ
                     Guest student at Sternwarte Sonneberg
                     Zentralinsitut fur Astrophysik der
                     Akademie der Wissenschaften der DDR
                        DDR - 6400, Sonneberg