TITLE: GCN CIRCULAR NUMBER: 45877 SUBJECT: EP261006a: Xinglong 2.16m/BFOSC optical follow-up observations DATE: 26/10/09 14:54:25 GMT FROM: Xinglong Observatory at National Astronomical Observatories (NAOC), Chinese Academy of Sciences (CAS) Junbo-Zhang (NAOC), Junjie-Jin (NAOC), Rui-Zhu (NAOC), Haiyang-Mu (NAOC), Feng-Xiao (NAOC), Yuguang-Sun (NAOC), Jie-Zheng (NAOC), Dong-Xu (NAOC), Zhou-Fan (NAOC), Hong-Wu (NAOC) report on behalf of a large collaboration We performed optical observations of the field of EP261006a (Lao et al., GCN 45826), classified as a possible TDE (Eyles-Ferris et al., GCN 45831; Jiang et al., GCN 45833), in the g, r, and i bands using the 2.16-m telescope located at Xinglong, Hebei, China. In each band, 3 × 300 s exposures were taken, with a median observation time of 2026-10-08T15:35:59, approximately 45.8 hours after the EP-WXT trigger (2026-10-06T17:49:57). We measure preliminary magnitudes of g = 18.49 ± 0.04, r = 19.39 ± 0.15, and i = 19.01 ± 0.08 mag (AB) for the host-subtracted optical counterpart, calibrated against nearby stars from the Pan-STARRS catalog. The stacked g, r, and i images have 5σ limiting magnitudes of ~20.68, 20.41, and 20.10 mag, respectively. We summarize our observation results as follows: Obs. No. | Time (UTC) | Exposure Time (s) | Filter | Apparent mag (AB) | Telescope Name 1 | 2026-10-08T15:14:46 | 3x300 s | g | 18.49 ± 0.04 | 2.16-m telescope 2 | 2026-10-08T15:30:51 | 3x300 s | r | 19.39 ± 0.15 | 2.16-m telescope 3 | 2026-10-08T15:46:46 | 3x300 s | i | 19.01 ± 0.08 | 2.16-m telescope