TITLE: GCN CIRCULAR NUMBER: 43717 SUBJECT: Fermi GRB 260212A: Global MASTER-Net observations report DATE: 26/02/12 19:15:22 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-Kislovodsk robotic telescope [1] located in Russia (Lomonosov MSU, Kislovodsk Solar Station of Pulkovo observatory) started inspect of the Fermi GRB 260212A ( Fermi GBM team, GCN 43716) errorbox 552 sec after notice time and 585 sec after trigger time at 2026-02-12 17:58:53 UT, with upper limit up to 18.0 mag. The observations began at zenith distance = 59 deg. The sun altitude is -37.1 deg. The galactic latitude b = 40 deg., longitude l = 111 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=3132416 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 645 | 2026-02-12 17:58:53 | MASTER-Kislovodsk | (15h 16m 06.75s , +73d 36m 46.3s) | C | 120 | 18.0 | 786 | 2026-02-12 18:01:14 | MASTER-Kislovodsk | (15h 16m 08.64s , +73d 36m 52.0s) | C | 120 | 17.5 | 926 | 2026-02-12 18:03:34 | MASTER-Kislovodsk | (15h 16m 10.47s , +73d 36m 57.7s) | C | 120 | 17.6 | 1068 | 2026-02-12 18:05:56 | MASTER-Kislovodsk | (15h 16m 12.12s , +73d 37m 03.6s) | C | 120 | 17.7 | 1209 | 2026-02-12 18:08:16 | MASTER-Kislovodsk | (15h 16m 13.41s , +73d 37m 09.3s) | C | 120 | 17.4 | 1652 | 2026-02-12 18:16:09 | MASTER-Kislovodsk | (15h 10m 30.28s , +72d 55m 28.4s) | C | 60 | 17.0 | 1860 | 2026-02-12 18:19:38 | MASTER-Kislovodsk | (15h 30m 36.29s , +74d 48m 40.5s) | C | 60 | 17.3 | 2274 | 2026-02-12 18:26:31 | MASTER-Kislovodsk | (15h 03m 57.80s , +76d 45m 03.8s) | C | 60 | 17.0 | 2516 | 2026-02-12 18:30:34 | MASTER-Kislovodsk | (15h 52m 21.24s , +72d 54m 23.0s) | C | 60 | 17.3 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. 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