TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4422 SUBJECT: GRB051211B: optical observations DATE: 06/01/02 12:34:50 GMT FROM: Alexei Pozanenko at IKI, Moscow D. Sharapov (MAO, and NOT La Palma), N.Marshalkina, M. Ibrahimov (MAO), A.Pozanenko (IKI), V.Rumyantsev (CrAO) on behalf of larger GRB follow up collaboration report: We observed refined error box of X-ray afterglow detected by Swift/XRT (La Parola et al. GCN 4338) of GRB051211B (Mereghetti et al. GCN 4327) with 1.5m telescope of Maidanak Astronomical Observatory on Dec. 12 and Dec.17. Sets of R images of 10x180 s were accumulated in both epochs. We do not detect the candidate in afterglow at coordinates RA(J2000) =23:02:41.57, Dec(J2000) =+55:04:51.5 mentioned by M. Jelinek et al. in GCN 4358. Object to the North-West from fading object referred in GCN 4358 as a possible host galaxy is well detected in our combined images in the both epochs. Using USNO-B1.0 catalog we estimate upper limit and possible host galaxy brightness as following: Obs. time, Exposure, Galaxy, Mag.(UL),Seeing (UT) (s) R(mag) Dec.12 17:16-17:56 1800 21.077+/-0.075 22.0 1.2" Dec.17 14:09-14:45 1800 21.167+/-0.060 22.3 1.1" The source mentioned by Khamitov et al in GCN 4336 is marginally detected on our combined image on Dec.12, and is unlikely to be an afterglow. We would note that the candidate in afterglow at coordinates RA(J2000) =23:02:41.57, Dec(J2000) =+55:04:51.5 is well visible in RTT150 image. Combined images can be found at http://grb.rssi.ru/GRB051211b/.