TITLE: GCN CIRCULAR NUMBER: 12936 SUBJECT: GRB 120211A: MITSuME Okayama Ks-band Observation DATE: 12/02/12 13:28:43 GMT FROM: Kenshi Yanagisawa at OAO/NAOJ Kenshi Yanagisawa, Daisuke Kuroda, Yasuhiro Shimizu, Kiichi Okita (OAO/NAOJ), Michitoshi Yoshida (Hiroshima-U), Kouji Ohta(Kyoto-U), and Nobuyuki Kawai(Tokyo Tech.) report on behalf of the MITSuME collaboration: We observed the field of GRB120212A (Sonbas et al., GCNC 12930, Perri et al., GCNC 12934) in Ks-band with a wide-field NIR camera at Okayama Astrophysical Observatory (Japan). The camera has an effective aperture of 0.91m. Observations started from 10:01 UT on 12th February, 49.6 min after the BAT trigger, to 10:44 UT. The total exposure of 35 min was successfully obtained. In our co-add image, we found a single point source at R.A.(J2000) = 02:52:24.08 DEC (J2000) = -18:01:14.8 with an uncertainty of of about 2 arcsec. The position is consistent with the report by Guidorzi et al. (GCNC 12929) We estimate the magnitude Ks = 15.13 +/- 0.19 (Vega). The calibration was made against 2MASS field stars. T0+[min] MID-UT T-EXP[min] Ks ------------------------------------------------------------ +71.2 10:22: 35.0 15.13 +/- 0.19 (Vega) ------------------------------------------------------------ T0+ : Elapsed time after the burst [min] T-EXP: Total Exposure time [min]