TITLE: GCN CIRCULAR NUMBER: 43353 SUBJECT: Swift GRB 251230A: Global MASTER-Net OT detection DATE: 26/01/08 18:03:52 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru> D. Buckley (South African Astronomical Observatory), V. Lipunov, V.Kornilov, E. Gorbovskoy, K. Zhirkov, N.Tyurina, P.Balanutsa, A.Kuznetsov, V.Senik, D. Vlasenko, G.Antipov, D.Zimnukhov, E.Minkina, A.Chasovnikov, V.Topolev, D.Kuvshinov, D. Cheryasov, Ya.Kechin, Yu.Tselik, A. Sosnovskij (Lomonosov Moscow State University, SAI, Physics Department), R. Podesta, C.Lopez, F. Podesta, C.Francile (Observatorio Astronomico Felix Aguilar OAFA), R. Rebolo, M. Serra (The Instituto de Astrofisica de Canarias), O.A. Gress, N.M. Budnev, O.Ershova (Irkutsk State University, API), L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez (INAOE, Guillermo Haro Astrophysics Observatory), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), V. Yurkov, A. Gabovich (Blagoveschensk Educational State University) MASTER-SAAO robotic telescope [1] located in South Africa (South African Astronomical Observatory) was pointed to the GRB 251230A ( S. Lanava et al., GCN 43252) 1908 sec after notice time and 1930 sec after trigger time at 2025-12-30 01:53:52 UT. On our first (180s exposure) set we found 1 optical transient within Swift error-box (ra=179.892 dec=11.415 r=0.05) brighter than 19.2. T-Tmid Date Time Expt. Ra Dec Mag ---------|---------------------|-------|-----------------|-----------------|------- 2020 2025-12-30 01:53:52 180 (11h 59m 35.40s , +11d 26m 18.8s) 16.4 The 5-sigma upper limit has been about 19.2mag The message may be cited. [1] - V.M. Lipunov, V.G. Kornilov, E.S. Gorbovskoy, N.A. Tiurina & A.S.Kuznetsov, 2023, Astronomical Robotic Networks and Operative Multichanel Astrophysics, Lomonosov MSU PRESS, 591pp.http : // www.pereplet.ru/lipunov/625.html View this GCN Circular online at https://gcn.nasa.gov/circulars/43353. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...