TITLE: GCN CIRCULAR NUMBER: 40916 SUBJECT: GRB 250702F: TRT Optical Observation DATE: 25/07/03 14:23:55 GMT FROM: Zipei Zhu at NAOC <zpzhu@nao.cas.cn> J. An (NAOC), K. Noysena, K. Chanchaiworawit, S. Tinyanont (NARIT), S.Y. Fu (HUST), X. Liu, Z.P. Zhu, S.Q. Jiang, L.B. He, D. Xu (NAOC) report on behalf of a large collaboration: We observed the field of GRB 250702F detected by Swift/BAT (Klingler et al., GCN 40894) and Fermi/GBM (Fermi GBM Team, GCN 40892), using the 0.7-m telescope of the Thai Robotic Telescope network (TRT), located at Fresno, California, U.S.A. (SRO). Observations started at 05:17:25 UTC on 2025-07-03, i.e., ~ 8.18 hr after the Swift/BAT trigger and several frames in the R & I band were obtained. We clearly detect the optical afterglow (Jelinek et al., GCN 40895; Kumar et al., GCN 40896; Lipunov et al., GCN 40899; Martin-Carrillo et al., GCN 40900; Angulo et al., GCN 40907; Becerra et al., GCN 40911; Brivio et al., GCN 40913) in our images. Preliminary photometry shows that the source has R ~ 19.4 mag at 8.32 hr post-trigger and I ~ 18.6 mag at 8.61 hr post-trigger, calibrated with Pan-STARRS DR2 catalog and not corrected for Galactic extinction. View this GCN Circular online at https://gcn.nasa.gov/circulars/40916. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...