TITLE: GCN CIRCULAR NUMBER: 19004 SUBJECT: GRB 160131A: TSHAO optical observations DATE: 16/02/08 22:04:39 GMT FROM: Alexei Pozanenko at IKI, Moscow E. Mazaeva (IKI), I. Reva (Fesenkov Astrophysical Institute), A. Volnova (IKI), A. Kusakin (Fesenkov Astrophysical Institute), A. Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration: We observed the Swift GRB 160131A (Page et al., GCN 18951) with Zeiss-1000 (East) 1-m telescope of Tien Shan Astronomical Observatory. We obtained several images in R filter on Feb. 06 and Feb. 07.The optical afterglow (Page et al., GCN 18951; Yurkov et al., GCN 18952; Guidorzi et al., GCN 18953; Xin et al., GCN 18954; Xin et al., GCN 18955; Watson et al., GCN 18956) is detected on Feb. 06 and not detected on Feb. 07. Preliminary photometry is following Date UT start t-T0 Filter Exp. OT Err. (mid, days) (s) 2016-02-06 13:45:54 6.26762 R 21*300 22.40 0.3 2016-02-07 13:30:04 7.25330 R 21*300 >22.40 (3sigma) Photometry is based on nearby USNO-B1.0 stars USNO-B.1_id R2 0829-0078223 15.70 0829-0078147 14.56 0829-0078167 17.71 0829-0078222 18.96 0829-0078226 18.69 0829-0078129 17.62