TITLE: GCN CIRCULAR NUMBER: 5828 SUBJECT: GRB 061121: Optical observation at the KANATA 1.5m telescope DATE: 06/11/21 17:42:48 GMT FROM: Makoto Uemura at Hiroshima U M. Uemura, A. Arai, and T. Uehara (Hiroshima Univ.), report on behalf of the KANATA GRB team: We started optical imaging of the field of GRB061121 using the TRISPEC attached to the KANATA 1.5-m telescope at Higashi-Hiroshima Observatory, Japan. We detected the optical afterglow reported in GCN 5823 and 5824 in our images taken with the exposure time of 123 s and the Rc filter. Using the comparison star USNOA2.0 0750-0732588 assuming Rc=14.2, our preliminary analysis yielded the following photometric result: UT Time after the burst (s) Rc mag Nov. 21.71928 6797 18.539 +/- 0.074 We keep time-series observations.