TITLE: GCN CIRCULAR NUMBER: 10904 SUBJECT: GRB100628A : MOA optical upper limit DATE: 10/06/29 05:31:35 GMT FROM: Suzuki Daisuke at MOA-II D. Suzuki, K. Omori, F. Hayashi, S. Kobara, H. Naito and T. Sako (STE Lab. , Nagoya Univ.) on behalf of the MOA Collaboration repot : We searched for an optical afterglow of GRB100628A (GCN 10895, S. Immler et al.) starting from 08:16:43 UT on 2010 June 28 ( 3 minutes after the burst) with the MOA-II 1.8m telescope at Mt.John observatory in New Zealand. In a single image of a 300 sec exposure with a wideband Red filter (center wavelength ~ 750nm and FWHM ~ 250nm), we did not find any object within the error circle of the Swift XRT source position (GCN 10899, R.L.C. Starling et al.). A 3 sigma upper limit is set in the I magnitude at 22.7 mag. This photometry was done by using the DoPhot and calibrated against the USNO-B1.0 catalog stars, and not corrected for the Galactic extinction.