TITLE: GCN CIRCULAR NUMBER: 10738 SUBJECT: GRB 100511A, RIMOTS optical upper limits DATE: 10/05/11 19:11:25 GMT FROM: Arata Daikyuji at Miyazaki U A.Daikyuji, N.Ohmori, Y.Nisioka, K.Noda, M.Yamauchi (University of Miyazaki) We have observed the field covering the error circle of GRB GRB100511A (Swift trigger 421695) with the unfiltered CCD camera on the 30-cm telescope at University of Miyazaki. The observation was started 14:19:42 UT, about two and a half hours after the Swift trigger time. We have compared our data of 30 sec exposures with the USNO-A2.0 catalog, There is no new source at the reported position. the upper limits are as follows: -------------------------------------------------------------- Start(UT) End(UT) Num. of frames Limit (mag.) -------------------------------------------------------------- 14:19:42 14:20:12 1 14.9 14:19:42 15:02:15 26 16.0 ---------------------------------------------------------------