TITLE: GCN CIRCULAR NUMBER: 13988 SUBJECT: GRB 121123A: optical observations DATE: 12/11/24 01:50:55 GMT FROM: Alexei Pozanenko at IKI, Moscow A. Volnova (SAO MSI, IKI), A. Stepura (UAFO), A. Matkin (UAFO), D. Erofeev (UAFO), I. Molotov (KIAM), A. Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration: We observed the field of the Swift GRB 121123A (Helder et al., GCN 13982) with VT-50 (0.5-m) telescope and GAS-250 of UAFO/ISON-Ussuriysk observatory starting on Nov. 23 (UT) 10:10:15, i.e. 6 minutes after burst trigger. We took several unfiltered images of 30 s. We do not detect detect afterglow (Helder et al., GCN 13982; Zhao et al., GCN 13983) in a stacked images. Preliminary photometry of a stacked image obtained with VT-50 is based on USNO-B1.0 stars (R2): T_start T0+, Filter, exposure, UL (3 sigma) (UT) mid (d) (s) 10:10:15 0.02793 none 90x30 18.1