TITLE: GCN CIRCULAR NUMBER: 44909 SUBJECT: GRB 260610B: TRT optical observation DATE: 26/06/11 09:13:48 GMT FROM: Zipei Zhu at NAOC <zpzhu@nao.cas.cn> Z.-P. Zhu (NAOC), K. Noysena, K. Chanchaiworawit, S. Tinyanont (NARIT), J. An (NAOC), X. Liu, S.-Q. Jiang, L.-B. He, D. Xu (NAOC), S.-Y. Fu (HUST) report: We observed the field of GRB260610B detected by Fermi (Fermi GBM team, GCN 44901) , using the 0.7-m telescope of the Thai Robotic Telescope network (TRT), located at Fresno, California, U.S.A (SRO). Observation started at 2026-06-11 08:22:08 UT, i.e., ~ 0.36 days post-burst, and a series of R-band frames were obtained. The previously reported optical counterpart (O'Neill et al., GCN 44903; Watson et al., GCN 44905) is clearly detected in our stacked images with a brightness of R = 18.92 +/- 0.05, calibrated with Pan-STARRS DR2 stars in the field and not corrected for Galactic extinction. View this GCN Circular online at https://gcn.nasa.gov/circulars/44909. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...