TITLE: GCN CIRCULAR NUMBER: 35460 SUBJECT: GRB 240101A: Terskol Zeiss-2000 optical observations DATE: 24/01/02 16:26:17 GMT FROM: Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru> A. Volnova (IKI), P. Phorunzij (INASAN), A. Pozanenko (IKI), N. Pankov (IKI, HSE), S. Belkin (IKI, HSE) report on behalf of GRB IKI FuN: We observed the GRB 240101A (Cenko et al., GCN 35448) with Zeiss-2000 telescope of Terskol observatory starting on 2024-01-01 (UT) 16:10:24. Within enhanced Enhanced Swift-XRT position (Beardmore et al., GCN 35452) we do not detect any optical objects. However we marginally detected the object at coordinates (J2000) 00:41:23.50 +8:30:58.48, which is 3.4 arcsec from XRT position (Beardmore et al., GCN 35452). Preliminary photometry of the marginally detected object is following. Date UT start t-T0 Filter Exp. OT Err. UL. (mid, days) (s) S/N 2024-01-01 16:10:24 0.1823 R 19*60 23.7 2.0 23.0 The photometry is based on the nearby PS1 stars photometry (Lupton transformations) RA Dec c R(Lupton) 00:41:22.24 +08:31:56.6 16.277 +/- 0.012 00:41:17.90 +08:31:41.5 18.013 +/- 0.014 View this GCN Circular online at https://gcn.nasa.gov/circulars/35460. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...