TITLE:   GCN CIRCULAR
NUMBER:  17834
SUBJECT: GRB 150518A: SAO RAS optical observations
DATE:    15/05/20 18:42:42 GMT
FROM:    Moskvitin Alexander at SAO RAS  <mosk@sao.ru>

A. S. Moskvitin (SAO RAS) report on behalf of larger GRB follow-up
collaboration:

The field of GRB 150518A (Kawamuro et al.,  GCNC 17825; Sbarufatti et al.,
GCNC 17827) was observed with the Zeiss-1000, 1-m telescope of SAO RAS.
The observations were carried out on the May, 19, 20:10:25 -- 21:26:30 UT
(T - T0 ~ 23 hours). 12 x 300 sec frames in Rc filter were obtained.

We clearly detect the source mentioned by the other teams (Xu et al.,
GCNC 17829, 17832; Mao et al., GCNC 17830; Littlejohns et al., GCNC 17831).
The magnitude of the object is R = 21.2 +/- 0.1 is almost equal
to the magnitude of SDSS J153648.25+161946.9 (within the errors),
probable host galaxy of GRB, so we can not find a significant excess from
the
possible OT.

Photometry is based on the nearby stars, whose SDSS magnitudes were
transformed to UBVRI system. The magnitude of object is not corrected
for the Galactic extinction.