TITLE: GCN CIRCULAR NUMBER: 43912 SUBJECT: Fermi GRB 260303B: Global MASTER-Net observations report DATE: 26/03/03 19:17:13 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru> 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-SAAO robotic telescope [1] located in South Africa (South African Astronomical Observatory) started inspect of the Fermi GRB 260303B ( Fermi GBM team, GCN 43907) errorbox 20103 sec after notice time and 20130 sec after trigger time at 2026-03-03 18:59:50 UT, with upper limit up to 16.5 mag. The observations began at zenith distance = 82 deg. The sun altitude is -22.8 deg. The galactic latitude b = -87 deg., longitude l = 48 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=3166705 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 20160 | 2026-03-03 18:59:50 | MASTER-SAAO | (00h 37m 01.21s , -26d 50m 03.0s) | C | 60 | 16.2 | 20252 | 2026-03-03 19:01:22 | MASTER-SAAO | (00h 37m 03.97s , -26d 48m 23.8s) | C | 60 | 16.5 | 20344 | 2026-03-03 19:02:54 | MASTER-SAAO | (00h 36m 56.33s , -26d 49m 08.6s) | C | 60 | 16.4 | 20466 | 2026-03-03 19:04:26 | MASTER-SAAO | (00h 36m 55.39s , -26d 48m 01.6s) | C | 120 | 15.8 | 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 View this GCN Circular online at https://gcn.nasa.gov/circulars/43912. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...