TITLE:   GCN CIRCULAR
NUMBER:  33697
SUBJECT: GRB 230427A: GMG upper limit
DATE:    23/04/28 03:50:39 GMT
FROM:    Jirong Mao at Yunnan Obs <jirongmao@mail.ynao.ac.cn>

J. Mao, H.-C. Feng, and J.-M. Bai (YNAO) report:

We observed the field of GRB 230427A (Troja et al. GCN 33687) by the GMG telescope in Yunnan observatories.
The observation began from UT 14:52:28 April 27, 2023, about 4.3 hours from the trigger. We could not observe the optical
afterglow down to a magnitude limit of R~20.6.