TITLE: GCN CIRCULAR NUMBER: 35605 SUBJECT: GRB 240123A: Mondy optical afterglow observations DATE: 24/01/23 15:52:15 GMT FROM: Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru> N. Pankov (HSE, IKI), A. Pozanenko (IKI), E. Klunko (ISTP), S. Belkin (IKI) report on behalf of GRB IKI FuN: We observed the field of GRB 231117A (D'Ai et al., GCN 35602) with AZT-33IK telescope of Mondy observatory in R-filter starting on 2024-01-23 (UT) 14:00:48. We clearly detect a new fading object at coordinates (J2000) 13 17 23.87 +60 37 05.3 with uncertainties of 0.2 arcsec which is slightly differ from coordinates reported by UVOT (D'Ai et al., GCN 35602). The object is absent in SDSS catalogue. Preliminary photometry is following Date UT start t-T0 Exp. Filter OT Err. (mid, days) (s) 2024-01-23 14:00:48 0.126415 7x120 R 19.07 0.10 20.9 2024-01-23 14:20:48 0.144479 13x120 R 19.25 0.10 21.3 2024-01-23 14:46:49 0.163934 15x120 R 19.37 0.11 21.3 The photometry is based on nearby USNO-B1.0 R2 stars. View this GCN Circular online at https://gcn.nasa.gov/circulars/35605. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...