TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4308 SUBJECT: GRB051117B: optical observation DATE: 05/11/29 20:04:12 GMT FROM: Alexei Pozanenko at IKI, Moscow D. Sharapov, M. Ibrahimov (MAO), A.Pozanenko (IKI),V.Rumyantsev (CrAO) on behalf of larger GRB follow up collaboration report: We observed the error box of GRB051117b (Band et al., GCN 4281) with 1.5m telescope of Maidanak Astronomical Observatory. Set of R images were taken between Oct.17 (UT) 21:31 - 21:54. No source is detected in refined XRT error box (Beardmore et al., GCN 4304). We do not detect the extended source mentioned by Chen et al. in GCN 4285. Preliminary estimation of upper limit against of USNO A2.0 is following: Mid time, Exposure, Filter, Mag. (UT) (s) Nov.17 21:46 1080 R 21.0 (3 sigma UL) The message may be cited.