TITLE: GCN CIRCULAR NUMBER: 10198 SUBJECT: GRB 091127: CAHA 1.23m I-band observations DATE: 09/11/28 03:25:55 GMT FROM: Javier Gorosabel at IAA-CSIC J. Gorosabel (IAA-CSIC), A. de Ugarte Postigo (INAF/OAB), V. Terron (IAA-CSIC), M. Fernandez (IAA-CSIC), P. Kubanek (IAA-CSIC), M. Jelinek (IAA-CSIC), report on behalf of a larger collaboration: "We have detected the GRB 091127 optical afterglow (Smith et al. GCNC 10192; Immler et al. GCN 10193) by means of a single I-band frame (Texp=120s) taken with the CAHA 1.23m Telescope. The observations, carried out on Nov. 28.03862-28.04000 UT (~1.5 hours post burst) under poor weather conditions, yielded a preliminary I-band magnitude of I~16.4, assuming I=13.62 for the USNO-B1.0 star located at (RA,DEC) = (02:26:21.063,-18:57:19.02; J2000)."