TITLE: GCN CIRCULAR NUMBER: 10392 SUBJECT: GRB 100206A: YNAO-GMG observations DATE: 10/02/07 13:26:10 GMT FROM: Jirong Mao at INAF-OAB J. Mao (YNAO & INAF-OAB), D. Wang and J. Bai (YNAO) report on behalf of the GMG group: Starting 14h 44m UT, after more than 1 hour of the trigger, we observed the field of GRB 100206A (Krimm et al., GCN 10376) with one 2.4-m telescope located at Gao-Mei-Gu (GMG). We did not see the afterglow in the R-band image with exposure time 20 min. However, the nearby galaxy(Miller et al. GCN 10377) were clearly detected, the magnitude is about R ~ 21.5 referenced to one USNO star. This message might be cited.