TITLE: GCN CIRCULAR NUMBER: 42717 SUBJECT: EP251023a: Assy AZT-20 optical observations DATE: 25/11/17 13:07:17 GMT FROM: Alina Volnova at IKI RAS <alinusss@gmail.com> A. Volnova (IKI), A. Pozanenko (IKI), M. Krugov (FAI) report on behalf of IKI-GRB-FuN: We observed the field of the EP transient EP251023a (Wu et al., GCN 42388) in r' filter with the AZT-20 1.5m telescope of Assy-Turgen observatory starting on Oct., 23, 2025 (UT) 20:25:35, taking several exposures of 60 seconds. The optical counterpart (Wortley et al., GCN 42387; Li et al., GCN 42389; Liu et al., GCN 42391; Mandarakas et al., GCN 42400; Lipunov et al., GCN 42405; Selezneva et al., GCN 42406; Mohan et al., GCN 42411; Rakotondrainibe et al., GCN 42420; Rajabov et al., GCN 42422; Volnova et al., GCN 42468; Volnova et al., GCN 42716) is clearly detected in the stacked frame. The preliminary photometry is the following: Date UT start t-T0 Exp. Filter OT Err. UL (mid,days) (n*s) (3sigma) 2025-10-23 20:25:35 0.76378 30*60 r' 20.22 0.06 22.2 The photometry is based on several nearby PS1 stars (AB-system) and is not corrected for the Galactic extinction. View this GCN Circular online at https://gcn.nasa.gov/circulars/42717. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...