TITLE: GCN CIRCULAR NUMBER: 10248 SUBJECT: GRB 091127: GAO 150cm telescope Optical Observation DATE: 09/12/05 08:59:45 GMT FROM: Kenzo Kinugasa at Gunma Astro. Obs/Japan K. Kinugasa, S. Honda, O. Hashimoto, H. Takahashi, H. Taguchi (Gunma Astronomical Observatory) report: The position of GRB 091127 (Troja et al., GCN 10191) was observed with the 150 cm telescope of Gunma Astronomical Observatory. Starting at 13:45:44 and 14:04;55 UT on Nov.28 ( about 14.3 and 14.7 hours after the trigger), Ic and Rc frames were acquired for sets of 5 x 3-min and 5 x 3-min exposures, respectively. We detected the optical counterpart (e.g., Smith et al., GCN 10192; Immler et al., GCN 10193) in all frames. We estimated the Rc and Ic magnitudes relative to USNO-B1.0 R2 and I magnitudes, respectively. mid-UT T0+(d) exp mag. ----------------------------------------------- 13:54:51 0.6035 5x3min Rc=18.37+-0.13 14:16:39 0.6187 5x3min Ic=18.62+-0.32 ----------------------------------------------- The R magnitude is well fitted with the fading trend from the other observations (e.g., Xu et al. GCN 10205; Sndreev et al. GCN 10207; Haislip et al. GCN 10219).