TITLE: GCN CIRCULAR NUMBER: 7668 SUBJECT: GRB 080503: MITSuME Akeno optical upper limits DATE: 08/05/03 16:35:16 GMT FROM: Nobuyuki Kawai at Tokyo Tech Y.A. Mori, Y. Kudou, T. Shimokawabe and N. Kawai (Tokyo Tech) report on behalf of the MITSuME collaboration: We observed the error box of GRB 080503 (Mao et al. GCN 7665) with the 3-color 50cm MITSuME Telescope at Akeno, Japan starting at 2008-05-03 12:31:53 UT, 5.4 min after the trigger. In the co-added images of Ic, Rc, and g' bands, we did not detect any afterglow candidate in the XRT error circle. The 3-sigma limiting magnitudes based on USNO-B1.0 (I-band) and NOMAD (R-band,g'-band) stars are following. Filter start (UT) end (UT) Exposure LimitMag --------------------------------------------------- g' 12:31:53 12:41:03 9 x 60 s 18.8 Rc 12:31:53 12:41:03 9 x 60 s 19.2 Ic 12:31:53 12:41:03 9 x 60 s 18.1 ----------------------------------------------------