TITLE: GCN CIRCULAR NUMBER: 23308 SUBJECT: GRB 181002A: Mondy optical upper limit DATE: 18/10/05 07:28:44 GMT FROM: Alexei Pozanenko at IKI, Moscow E. Mazaeva (IKI), A. Pozanenko (IKI), E. Klunko (ISTP), A. Volnova (IKI) report on behalf of of larger GRB follow-up collaboration: We observed the field of the GRB 181002A (Gropp et al., GCN 23290) with AZT-33IK telescope of Sayan observatory (Mondy). We obtained several images in R-filter starting on Oct. 02 (UT) 16:31:56. We do not detect any object within enhanced Swift-XRT position (Beardmore et al., GCN 23292). Preliminary photometry of the field is following. Date UT start t-T0 Filter Exp. OT Err. UL(3sigma) (mid, days) (s) 2018-10-02 16:31:56 0.23281 R 58*60 n/d n/d 22.9 The photometry is based on nearby SDSS-DR12 stars SDSS-DR12_id R(Lupton) J041903.61+151252.8 18.69 J041903.16+151309.7 18.40 J041848.32+151242.2 16.52 J041904.57+151201.2 17.35 J041857.89+151107.8 17.14