TITLE: GCN CIRCULAR NUMBER: 35691 SUBJECT: GRB 240204A: Mondy optical afterglow observations DATE: 24/02/06 07:50:17 GMT FROM: Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru> S. Belkin (IKI, HSE), N. Pankov (HSE, IKI), E. Klunko (ISTP), A. Pozanenko (IKI) report on behalf of IKI-GRB-FuN: We observed the GRB 240204A (Fermi-GBM team GCN 35664, Cenko et al. GCN 35666, Pozanenko et al. GCN 35670, Leonini et al. GCN 35672, Pérez-Fournon et al. GCN 35673, Dainotti et al. GCN 35677, Bochenek et al. GCN 35678; Adami et al. GCN 35690) with AZT-33IK telescope of Mondy observatory starting on 2024-02-04 (UT) 16:05:26 and 2024-02-05 (UT) 13:10:09. Preliminary photometry of the afterglow based on USNO-B1.0 (R2) nearby stars is following Date UT start t-T0 Filter Exp. OT Err. UL(3sigma) (mid, days) (s) 2024-02-04 16:05:26 0.04292 R 480 19.90 0.10 21.9 2024-02-04 16:13:26 0.04847 R 480 20.01 0.11 21.8 2024-02-04 16:21:26 0.05403 R 480 19.93 0.10 21.9 2024-02-04 16:29:27 0.05959 R 480 19.85 0.09 21.8 2024-02-04 17:31:00 0.11345 R 2400 20.55 0.10 22.5 2024-02-05 13:10:09 0.96772 R 8400 22.4 0.2 23.1 View this GCN Circular online at https://gcn.nasa.gov/circulars/35691. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...