TITLE: GCN CIRCULAR NUMBER: 19980 SUBJECT: GRB 161004A: TSHAO optical observations DATE: 16/10/04 17:44:41 GMT FROM: Alexei Pozanenko at IKI, Moscow E. Mazaeva (IKI), I. Reva (Fesenkov Astrophysical Institute), A. Kusakin (Fesenkov Astrophysical Institute), A. Volnova (IKI), A. Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration: We observed the field of GRB 161004A (Evans et al., GCN 19979) with Zeiss-1000 (East) 1-m telescope of Tien Shan Astronomical Observatory. We obtained several images in R filter starting on Oct. 04 (UT) 13:36:52. In the XRT error circle we do not detect any new object. Wa do not detect also candidate afterglow (Evans et al., GCN 19979). Preliminary photometry of a combined image is following Date UT start t-T0 Filter Exp. OT Err. UL (mid, days) (s) 2016-10-04 13:36:52 0.04321 R 15*180 n/d n/d 21.9 Photometry is based on nearby SDSS-DR9 stars (Lupton transformations): SDSS-DR9_id R(Lupton) J173243.09-005731.3 17.04 J173250.91-005842.7 16.77 J173251.94-005803.2 15.75 J173253.88-005801.6 15.62 J173253.02-005938.3 16.02 J173232.00-005640.3 16.34 J173227.11-005646.8 16.41 J173227.04-005816.8 16.51 J173227.48-005856.9 16.62 J173236.27-010018.1 16.96 J173241.54-005823.1 16.26 A finding chart can be found at http://grb.rssi.ru/GRB161004A/GRB161004A_TSHAO_161004_XRT_UVOT.png