TITLE: GCN CIRCULAR NUMBER: 18721 SUBJECT: V404Cyg Swift Trigger 668097: TSHAO optical observations DATE: 15/12/24 18:31:34 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 V404 Cyg after Swift BAT trigger 668097 (Barthelmy et al., GCN 18716) with Zeiss-1000 (East) 1-m telescope of Tien Shan Astronomical Observatory. Observations started on Dec., 23 (UT) 12:19:13. We obtained 165 images in R-filter of 30 s exposure. Preliminary light curve http://grb.rssi.ru/V404_Cyg/v404Cyg_20151223_lc.pngof the V404 Cyg can be found in http://grb.rssi.ru/V404_Cyg/v404Cyg_20151223_lc.png Photometry is based on following USNO-B1.0 stars ID R2 USNO-B1.0_id R2 1238-0435152 15.98 1239-0424177 14.99 1239-0424179 15.61 1238-0435111 16.33