TITLE: GCN CIRCULAR NUMBER: 37040 SUBJECT: EP240801a: Continued optical observations at ZTSh (CraO) DATE: 24/08/05 12:49:48 GMT FROM: Alexei Pozanenko at IKI, Moscow <grb.alex@gmail.com> N. Pankov (HSE, IKI), V. Rumyantsev (CrAO), A. Pozanenko (IKI) report on behalf of GRB-IKI-FuN: We observed the field of EP240801a (Zhou et al, GCN 36997) with ZTSh 2.6 m telescope of CrAO. The observation were carried out in moderate conditions with seeing about 2.0 arcsec. We taken series of images in the R-filter. We clearly detect the optical counterpart (Fu et al, GCN 36998; Li et al, GCN 36999; Zheng et al, GCN 37000; Aryan et al, GCN 37002; An et al, GCN 37004; Pérez-Fournon et al, GCN 37007; Malesani et al, GCN 37008; Zhu et al, GCN 37010; Moskvitin & Spiridonova, GCN 37012; Quirola-Vásquez et al, GCN 37013; Moretti et al, GCN 37014; Turpin et al, GCN 37015; Pankov et al, GCN 37016; Mo GCN 37017, ) in the stacked images. Preliminary photometry is as follows: Date UT start t-T0 Exp. Filter OT Err. UL (mid, days) (s) (3sigma) 2024-08-02 20:41:58 1.493699 15*120 R 22.27 0.05 23.7 2024-08-03 19:43:38 2.456662 20*120 R 22.60 0.09 23.2 The magnitudes were calibrated using nearby stars from USNO-B1.0 catalog (R2 magnitudes) and not corrected for the Galactic extinction. View this GCN Circular online at https://gcn.nasa.gov/circulars/37040. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...