GCN Circular 15124
D. Xu (DARK/NBI), D.-Y. Ren, C. Cao, S.-M. Hu (SDU) report: We observed the XRT field of GRB 130821A (Jenke et al., GCN 15113; Kocevski et al., GCN 15115; Page et al., GCN 15123) centered at RA(J2000) = 20h 56m 38.44s and Dec(J2000) = -12d 02' 36.53", using the 1m telescope located in Weihai, Shandong, China. We obtained 9x300s SDSS r'-band frames under cloudy conditions at a mean time of 14:20 UT on 2013-08-24 (i.e., 2.997 days after the burst). No optical source is detected within the XRT error circle in the stacked image, down to r'>20.8 mag, calibrated with nearby SDSS field.