TITLE: GCN CIRCULAR NUMBER: 35909 SUBJECT: Swift GRB240309.61: Global MASTER-Net observations report DATE: 24/03/10 06:42:53 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs 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), D. Buckley (South African Astronomical Observatory), 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-Amur robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (Blagoveshchensk State Pedagogical University) was pointed to the Swift GRB240309.61 (trigger No 1219325,19h 59m 15.60s , +35d 08m 34.8s, R=0.00130556) errorbox 11103 sec after notice time and 11141 sec after trigger time at 2024-03-09 17:37:59 UT, with upper limit up to 17.0 mag. The observations began at zenith distance = 70 deg. The sun altitude is -38.0 deg. MASTER-Tavrida robotic telescope located in Russia (Lomonosov MSU, SAI Crimea astronomical station) was pointed to the Swift GRB240309.61 errorbox 28115 sec after notice time and 28152 sec after trigger time at 2024-03-09 22:21:31 UT, with upper limit up to 18.0 mag. The observations began at zenith distance = 85 deg. The sun altitude is -49.7 deg. The galactic latitude b = 3 deg., longitude l = 72 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=2395242 We obtain a following upper limits. Tmid-T0 | Site |Filt.| Expt. | Limit| Comment _________|_____________________|_____|_______|______|________ 11231 | MASTER-Amur | C | 180 | 16.7 | 12469 | MASTER-Amur | C | 180 | 17.0 | 12994 | MASTER-Amur | C | 180 | 16.8 | 28243 | MASTER-Tavrida | C | 180 | 15.1 | 29478 | MASTER-Tavrida | C | 180 | 16.5 | 30724 | MASTER-Tavrida | C | 180 | 17.0 | 31962 | MASTER-Tavrida | C | 180 | 17.2 | 32915 | MASTER-Tavrida | C | 180 | 17.2 | 33203 | MASTER-Tavrida | C | 180 | 17.4 | 34088 | MASTER-Tavrida | C | 180 | 16.8 | 34456 | MASTER-Tavrida | C | 180 | 16.9 | 35699 | MASTER-Tavrida | C | 180 | 17.2 | 35992 | MASTER-Tavrida | C | 180 | 17.4 | 36937 | MASTER-Tavrida | C | 180 | 17.4 | 38183 | MASTER-Tavrida | C | 180 | 17.7 | 39465 | MASTER-Tavrida | C | 180 | 17.8 | 40756 | MASTER-Tavrida | C | 180 | 17.9 | 41963 | MASTER-Tavrida | C | 180 | 18.0 | 43190 | MASTER-Tavrida | C | 180 | 17.9 | 44486 | MASTER-Tavrida | C | 180 | 17.8 | 45715 | MASTER-Tavrida | C | 180 | 16.7 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited.