TITLE: GCN CIRCULAR NUMBER: 11392 SUBJECT: GRB 101030A : MOA optical observation DATE: 10/11/06 18:06:59 GMT FROM: Suzuki Daisuke at MOA-II D. Suzuki, K. Omori, S. Kobara, H. Naito and T. Sako (STE Lab, Nagoya Univ.) on behalf of the MOA Collaboration report: We searched for an optical afterglow of GRB101030A (GCN 11386, Melandri et al.) starting from 15:59:39 UT on 2010 Oct. 30th with the MOA-II 1.8m telescope at Mt.John observatory in New Zealand. The images were taken with a wideband Red filter (center wavelength ~ 750nm and FWHM ~ 250nm), and we found a new source within the error circle of the Swift XRT source position (GCN 11387). The estimated magnitudes are the followings. t-t0(sec) Imag err exp. ------------------------- 190 20.0 2.3 300 610 19.5 4.0 100 ------------------------- Large errors in the magnitude estimation are due to the observations during dawn and under the moon light. Consequently, relatively small number of field stars affects in the large errors. These magnitudes were calibrated against the USNO-B1.0 catalog stars, and not corrected for the Galactic extinction.