TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5606 SUBJECT: GRB 060923C, optical observation DATE: 06/09/25 01:20:00 GMT FROM: Shouta Maeno at U.of Miyazaki S.Maeno, E.Sonoda, M.Yamauchi (University of Miyazaki) We have observed the field covering the error circle of GRB 060923C (GCN 5591) with the unfiltered CCD camera on the 30-cm telescope at University of Miyazaki. The observation was started 15:01:30 UT on Sep. 23. We have compared our data of 30 sec exposures with the USNO-A2.0 catalog, there is no new source at the position reported by GCN 5591. The upper limit is as follows: -------------------------------------------------------------- Start(UT) End(UT) Num. of frames Limit (mag.) -------------------------------------------------------------- 15:01:30 15:32:39 17 ~17.5 ---------------------------------------------------------------