TITLE: GCN CIRCULAR NUMBER: 18035 SUBJECT: GRB 150711A: Burakan-ISON optical observations DATE: 15/07/18 22:00:01 GMT FROM: Alexei Pozanenko at IKI, Moscow E. Mazaeva (IKI), V. Nevskiy (ISON) I. Molotov (KIAM), A. Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration: We observed the field of GRB 150711A (Bernardini et al. GCN 18011) with the 40 cm telescope of Burakan-ISON observatory starting on Jul., 11 (UT) 18:36:16, i.e. ~13 min after burst trigger. We obtained several unfiltered images. In a combined image we do not detect any source within the XRT error box (Osborne et al. GCN 18012) down to a limiting magnitude of R = 16.9 Date UT start t-T0 Filter Exp. OT UL(3 sigma) (mid, days) (s) 2015-07-11 18:36:16 0.01250 none 9*60 n/d 16.9 The photometry is based on nearby USNO-B1.0 stars.