TITLE: GCN CIRCULAR NUMBER: 24688 SUBJECT: GRB 190530A: GWAC-F30 optical detection DATE: 19/05/31 01:42:46 GMT FROM: Liping Xin at NAOC, SVOM L. P. Xin, G. W. Li, R. S. Zhang, T. C. Zheng, J. Wang, J. Y. Wei, Y. G. Yang, E. W. Liang, X. G. Wang, H. L. Li, X. H. Han, X. M. Lu, L. Huang, H. B. Cai, Y. L. Qiu, Y. Xu, Y. J. Xiao, Y. T. Zheng, C. Wu, J. S. Deng, D. W. Xu, D. Turpin, W. L. Dong, P. P. Zhang and Jirong Mao report: We began to observe GRB 190530A (Fermi-GBM team, GCN 24676 ) with GWAC-F30cm telescope at 2019-05-30T12:48:46(UT), about 2.49 hour after the burst. GWAC-F30cm telescope is located at Xinglong observatory, China. The field of view is about 1.9*1.9 sqr. deg. The coordinates we used to make the observations was derived from Biltzinger et al., (GCN 24677). Due to the low elevation of this source at Xinglong observatory, only seven R-band images were obtained. The exposure time for each frame was 20 seconds. The afterglow was detected by stacking all the images. The coordinates is about RA=08:02:07.678 DEC=+35:28:47.14 J2000, consistent with the position reported by Lipunov et al., GCN 24680. The magnitude was R=15.1mag, calibrated by the nearby USNO R2 magnitudes. This message my be cited.