TITLE: GCN CIRCULAR NUMBER: 22853 SUBJECT: GRB 180626A: ISON-MN optical observations DATE: 18/06/26 11:25:47 GMT FROM: Alexei Pozanenko at IKI, Moscow L. Elenin (KIAM), E. Mazaeva (IKI), A. Pozanenko (IKI), A. Volnova (IKI), I. Molotov (KIAM) report on behalf of larger GRB follow-up collaboration: We observed the field of the Swift GRB 180626A (Evans et al., GCN 22850) with ISON-NM observatory. Observation started 51 s after burst trigger. We do not find optical afterglow (Evans et al., GCN 22850) in a combined image of first 5 frames. Preliminary photometry of the filed is following. Date UT start t-T0 Filter Exp. OT Err. UL (mid, days) (s) 2018-06-26 08:22:07 0.00146 CR 5* 20 n/d n/d 17.3 The photometry is based on several nearby USNO-B1.0 stars.