TITLE:   GCN CIRCULAR
NUMBER:  14458
SUBJECT: GRB 130427A: Weihai optical observations
DATE:    13/04/27 13:08:24 GMT
FROM:    Dong Xu at DARK/NBI  <dong.dark@gmail.com>

D. Xu (DARK/NBI), C. Cao, S.-M. Hu, C.-M. Zhang (SDU) report:

We observed the field of GRB 130427A (Maselli et al., GCN 14448) with
the 1m telescope located in Weihai, Shandong Province, China. A series
of I-, R-, V-, and B-band frames were obtained, and observations are
still ongoing.

Although under quite much cloud, at the afterglow position (Elenin et
al., GCN 14450; Perley, GCN 14451) we detect the optical counterpart
with R=15.5 mag, with a median time of 4.178 hr after the BAT trigger
and calibrated with nearby USNO B1 stars.