EP240801a: JinShan optical observations

We observed the field of EP240801a detected by EP/WXT (Zhou et al., GCN 36997), using the JinShan 100cm-C telescope (100C) located at Altay, Xinjiang, China. The observation started at 17:17:48 UT on 2024-08-01, ~ 8.20 hr after the EP/WXT trigger and ended at 22:06:04 UT the same night. A series of exposures were obtained in the Sloan g-, r-, i-, and z- filters. The previously reported optical counterpart by TRT (Fu et al. GCN 36998) has decayed to r = 21.44 +/- 0.06 at 9.63 hr after EP/WXT trigger, calibrated with nearby Pan-STARRS stars and not corrected for Galactic extinction. The optical counterpart has also been reported by GMG (Li et al., GCN 36999), KAIT (Zheng et al., GCN 37000), Kinder (Aryan et al., GCN 37002), LCO (An et al., GCN 37004; Pérez-Fournon et al., GCN 37007), and NOT (Malesani et al., GCN 37008). We acknowledge the excellent support from S.W. Luo, M.M. Yang, Z.K. Feng, Q.C. Zhao and L.F. Huo for enabling these observations.