TITLE: GCN CIRCULAR NUMBER: 15189 SUBJECT: GRB 130831A: optical observation in Chuguev AO DATE: 13/09/07 23:56:01 GMT FROM: Alexei Pozanenko at IKI, Moscow A. Volnova (IKI), Yu. Krugly (IA KhNU), I. Slyusarev (IA KhNU), I. Molotov (KIAM), A. Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration: We observed the afterglow (Hagen et al., GCN 15139; Guidorzi et al., GCN 15140) of the Swift GRB 130831A (Hagen et al., GCN 15139) with AZT-8 (0.7m) telescope of Institute of Astronomy, Kharkiv National University in R filter starting on Sep. 01 (UT) 19:37:49. A preliminary photometry of combined images is based on SDSS DR9 stars T_start T0+ Filter, Exposure, OT, OT_err (UT) (mid, d) (s) 2013-09-01T19:37:49 1.29474 R 28x120 21.26 0.07 Reference stars SDSS-DR9, (R mag, transformation by Lupton 2005) N SDSS id R(Lupton)errR 1 J235443.71+292539.3 13.491 0.016 2 J235438.60+292547.3 14.136 0.015 3 J235423.64+292452.8 17.120 0.016