TITLE: GCN CIRCULAR NUMBER: 40693 SUBJECT: Swift GRB250612.04: Global MASTER-Net observations report DATE: 25/06/12 01:14:39 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs V.Lipunov, E.Gorbovskoy, A.Kuznetsov, K.Zhirkov, I.Panchenko, N.Tiurina, P.Balanutsa, V.Topolev, D.Vlasenko, G.Antipov, A.Sankovich, Yu.Tselik, Ya.Kechin, V.Senik, A.Chasovnikov, K.Labsina, I. Gorbunov (Lomonosov MSU), O.Gress, N.Budnev (ISU), C.Francile, F. Podesta, R.Podesta, E. Gonzalez (Observatorio Astronomico Felix Aguilar (OAFA), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), A.Sosnovskij (CrAO), A. Gabovich, V.Yurkov (Blagoveschensk Educational StateUniversity), D.Buckley (SAAO), R.Rebolo (The Instituto de Astrofisica de Canarias), L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez (INAOE, Guillermo Haro Astrophysics Observatory) MASTER-OAFA robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Argentina (OAFA observatory of San Juan National University) was pointed to the Swift GRB250612.04 (trigger No 1323295,16h 43m 36.72s , -38d 54m 07.2s, R=0.05) errorbox 42 sec after notice time and 83 sec after trigger time at 2025-06-12 01:03:28 UT, with upper limit up to 16.6 mag. The observations began at zenith distance = 36 deg. The sun altitude is -42.8 deg. The galactic latitude b = 4 deg., longitude l = 345 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=2900722 We obtain a following upper limits. Tmid-T0 | Site |Filt.| Expt. | Limit| Comment _________|_____________________|_____|_______|______|________ 93 | MASTER-OAFA | C | 20 | 16.6 | 120 | MASTER-OAFA | C | 20 | 16.6 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited.