TITLE: GCN CIRCULAR NUMBER: 19102 SUBJECT: GRB 160225A: TSHAO optical afterglow detection DATE: 16/02/27 21:44:21 GMT FROM: Alexei Pozanenko at IKI, Moscow E. Mazaeva (IKI), A. Kusakin (Fesenkov Astrophysical Institute), I. Reva (Fesenkov Astrophysical Institute), A. Volnova (IKI), A. Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration: We observed the Swift GRB 160225A (Siegel et al., GCN 19075) with Zeiss-1000 (West, East) 1-m telescopes of Tien Shan Astronomical Observatory. We obtained several images in R filter starting on Feb. 25 (UT) 14:45:56. In the first images we do not detect any optical source (Mazaeva et al., GCN 19078). In combine images we detect afterglow (Yoshiiet al., GCN 19080; Kuroda al., GCN 19081; Wiersema al., GCN 19082). Preliminary photometry of combined images is following Date UT start t-T0 Filter Exp. OT Err. UL (mid, days) (s) *2016-02-25 14:45:56 0.07022 R 87*90 20.75 0.16 21.4 2016-02-25 15:30:59 0.09576 R 77*90 21.36 0.20 21.9 2016-02-25 17:58:10 0.18146 R 52*90 n/d n/a 21.7 *) Zeiss-1000 West telescope observations Photometry is based on SDSS-DR9 nearby stars SDSS-DR9_id R(Lupton) J105614.20+533500.1 15.35 J105714.63+533304.9 14.36 J105658.91+533304.1 15.77