TITLE: GCN CIRCULAR NUMBER: 37970 SUBJECT: GRB 241030A: SVOM/C-GFT optical observations DATE: 24/10/30 13:50:02 GMT FROM: Chao Wu at NAOC SVOM/C-GFT team: Chao WU (NAOC), Zhe Kang (CHO), Liping Xin(NAOC), Xuhui Han(NAOC), Pinpin Zhang (NAOC), Xiaomeng Lu (NAOC), Zhenwei Li (CHO), You Lv (CHO), Ruosong Zhang (NAOC), Yujie Xiao(NAOC) SVOM JSWG: Jian-Yan Wei (NAOC), Bertrand Cordier (CEA), Shuang-Nan Zhang (IHEP), Stéphane Basa (LAM), Arnaud Claret (CEA), Zi-Gao Dai (USTC), Frédéric Daigne (IAP), Jin-Song Deng (NAOC),Olivier Godet (IRAP), Andrea Goldwurm (APC), Diego Götz (CEA), Xu-Hui Han (NAOC), Cyril Lachaud (APC), En-Wei Liang (GXU), Yu-Lei Qiu (NAOC), Susanna Vergani (Obs.Paris), Jing Wang (NAOC), Chao Wu (NAOC), Li-Ping Xin (NAOC), Shao-Lin Xiong (IHEP), Bing Zhang (UNLV) We observed the field of GRB 241030A detected by Fermi/GBM (Fermi GBM team, GCN 37955) and Swift/BAT (Klingler et al., GCN 37956) on 2024-10-30T09:54:53 UT, ~ 4.09 hr after the trigger with C-GFT in the commissioning phase. A series of g, r and i band images were obtained with exposure time of 30s. The counterpart (Dichiara et al. GCN 37956, Watson et al., GCN 37957; Fernández-Rodríguez et al., GCN 37958; Zheng et al., GCN 37959; An et al., GCN 37960; Higuchi et al., GCN 37963, Qiu et al., GCN 37965, Lin et al. GCN 37966) was clearly detected in band g,r and i. The results are, (T-T0)_mid（sec) mag mag_err band ------------------------------------- 14825 17.50 +/- 0.07 i 14935 18.01 +/- 0.12 g 15143 17.84 +/- 0.09 r The photometry was calibrated with nearby PS1 star. We thank the observation assistant Bowen Li and Guangsheng Zhang at Jilin observatory for their excellent support. Chinese Ground Follow-up Telescope of SVOM mission is located at Jilin, Changchun Observatory, National Astronomical Observatories, CAS. It has FOV of 1.28 deg x 1.28 deg with a 4k*4k CMOS detector mounted on the primary focus of 1.2-meter-aperure telescope.