TITLE: GCN CIRCULAR NUMBER: 8629 SUBJECT: GRB081203A: Optical observations at Ishigaki DATE: 08/12/06 13:25:53 GMT FROM: Mizuki Isogai at NAOJ M. Isogai (IAO, NAOJ) and N. Kawai (Tokyo Tech) report with support of MITuME collaboration: We observed the field of GRB 081203A(Parsons, et al., GCN Circ. 8595) with the optical 3-color imager attached to the 105cm Murikabushi Telescope at Ishigakizima Astronomical Observatory in Japan from UT 19:52, 5.9 hours after the trigger. In the co-added images of Ic, Rc, and g' bands, we detected a fading point source and measured its magnitude. Photometric calibration was performed using the GSC2.3 catalogs. The results are following: MID-MJD MID-UT EXP-T g' Rc Ic ---------------------------------------------------------------------- 54803.837345 20:05:46 720.0 18.50+/-0.09 54803.837345 20:05:46 900.0 19.43+/-0.11 18.76+/-0.06 54803.847273 20:20:04 720.0 19.39+/-0.11 54803.848363 20:21:38 900.0 18.83+/-0.06 18.49+/-0.08 54803.859451 20:37:36 900.0 19.57+/-0.11 18.96+/-0.06 18.67+/-0.09 54803.870356 20:53:18 900.0 19.77+/-0.11 18.94+/-0.07 18.72+/-0.10 54803.881257 21:09:00 900.0 19.71+/-0.12 19.04+/-0.07 18.71+/-0.10