TITLE: GCN CIRCULAR NUMBER: 13221 SUBJECT: GRB 120404A : TNT optical observation DATE: 12/04/05 00:44:27 GMT FROM: L.P. Xin at NAOC L.P. Xin, J. Y.Wei, Y.L. Qiu, J. Wang, J.S. Deng, C. Wu, X. H. Han on behalf of EAFON report: We began to observe GRB 120404A (Stratta et al., GCN Circ. 13208) with Xinglong TNT telescope in R-band at 19:33:05(UT), 6.7 hours after the burst. The optical counterpart (Stratta et al., GCN Circ. 13208, Guidorzi et al. GCN Circ. 13209) was marginal detected with a brightness of 20.3 +/- 0.2 mag calibrated to USNO B1.0 R2 mag, at the mean time of 7.4 hours after the burst. Combined with the report by Guidorzi et al. ( GCN Circ. 13209 ), the brightness of this burst decayed by 1.5 magnitude in R-band during 4 min and 7.4 hour after the burst, corresponding to a shallow decay index of about 0.3 during this phase. Further observations are encouraged. This message may be cited. For more information about Xinglong GRBs Follow-up observations, please visit the website: http://www.xinglong-naoc.org:8080/grb/index.html We thank Liang Ma for performing these observations.