TITLE: GCN CIRCULAR NUMBER: 17803 SUBJECT: GRB 150423A: GMG observation limit DATE: 15/05/05 02:09:50 GMT FROM: Jirong Mao at Yunnan Obs J. Mao, Y. Fan and J.-M. Bai (YNAO) report: We observed the field of GRB 150423A (Pagani et al., GCN 17728) with the 2.4-meter optical telescope at Gao-Mei-Gu (GMG) station of Yunnan Observatory. Observations began from 17:11:14 UT, May 2nd, 2015, about 9 days after the trigger. We did not detect any source / rebrightening feature at the afterglow position down to a limit of z~21.0 mag with poor observational condition.