TITLE: GCN CIRCULAR NUMBER: 20340 SUBJECT: GRB 161224A: TSHAO optical observations DATE: 16/12/26 13:04:31 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 161224A (Swift trigger=728268, Cholden-Brownet al., GCN 20333) with Zeiss-1000 (East) 1-m telescope of Tien Shan Astronomical Observatory. We obtained several images in R filter starting on Dec. 25 (UT) 00:13:31 and Dec. 25 (UT) 23:45:12. We do not detect any evident variable source in the BAT ground-calculated position (Ukwatta al., GCN 20337). Within enhanced XRT position (Cholden-Brownet al., GCN 20338) we not detected any source. Preliminary photometry of the field is following Date UT start t-T0 Filter Exp. OT Err. UL (mid, days) (s) 2016-12-25 00:13:31 0.10201 R 16*180 n/d n/d 21.1 2016-12-25 23:45:12 1.07646 R 11*180 n/d n/d 20.7 Photometry is based on nearby USNO-B1.0 stars 0719-0341418 17.14 0720-0349085 17.50 0720-0348989 16.94 0719-0341338 15.94 A finding chart can be found in http://grb.rssi.ru/GRB161224A/GRB161224A_20161225_TSHAO_fc.png