GCN Circular 19680
E. Mazaeva (IKI), A. Kusakin (Fesenkov Astrophysical Institute), P. Minaev (IKI), I. Reva (Fesenkov Astrophysical Institute), A. Volnova (IKI), A. Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration: We observed the field of GRB 160625B (Dirirsa et al., GCN 19580; Burns et al. GCN 19581) with Zeiss-1000 (East) 1-m telescopes of Tien Shan Astronomical Observatory. We obtained several images in R filter on July 8 and 10. We detect optical afterglow of GRB 160625B (Troja et al., GCN 19588; Oates et al., GCN 19589). Preliminary photometry of a combined image is following Date UT start t-T0 Filter Exp. OT Err. UL (mid, days) (s) 2016-07-08 19:01:43 12.9172 R 30*300 21.60 0.15 22.7 2016-07-10 18:19:18 14.8713 R 29*300 21.64 0.08 23.3 Photometry is based on nearby USNO-B1.0 stars reported in GCN 19605 (Mazaeva et. al).