TITLE: GCN CIRCULAR NUMBER: 22929 SUBJECT: GRB 180705A: RTT150 optical upper limit DATE: 18/07/08 16:42:54 GMT FROM: Rodion Burenin at IKI, Moscow I. Bikmaev, E. Irtuganov, N. Sakhibullin (KFU/AST), R. Burenin, M. Pavlinsky, R. Sunyaev (IKI), I. Khamitov, S. Ozdemir (TUG), E. Gogus (Sabanci Uni.) report: We observed the field of GRB 180705A (Stamatikos et al., GCN 22902) with the Russian-Turkish 1.5-m optical telescope (RTT150, Bakirlitepe, TUBITAK National Observatory, Turkey) using the TFOSC instrument. We obtained series of Rc exposures in July 05, 2018 (6 frames x 600 sec, UT = 19:12 - 20:19), ~ 4 hours after the burst. Within enhanced Swift-XRT position (Goad et al., GCN 22906) we have not detected any object down to Rc =~ 23.5 mag in the combined image (calibrated against SDSS secondary standard stars). Our result confirms OT non-detections as published in other GCNs (Lipunov et al., GCN 22904, Watson et al., GCN 22911, Breeveld et al., GCN 22912, Mazaeva et al., GCN 22913).