TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3334 SUBJECT: GRB 050502b : optical observation at Lulin observatory DATE: 05/05/02 15:47:37 GMT FROM: Yuji Urata at RIKEN K. Sanchawala, W.L. Wu, K.Y. Huang, W.H. Ip(NCU), Y. Qiu, W. Zhou (BAO), Y.Q. Lou (THCA), Y. Urata (RIKEN) on behalf of the EAFON report: " We have imaged the Swift XRT position of GRB 050502b (Pagani. C. et al., GCN 3333) using 1-m telescope at Lulin Observatory, Taiwan. The R band observations started from 13.45 UT (~ 3.98 hours after the burst). The limiting magnitude of R-band co-added image is R~21.8 compared with USNO-B1.0 stars. No source was detected under the limiting magnitude at the XRT position." This message may be cited.