TITLE: GCN CIRCULAR NUMBER: 28759 SUBJECT: Swift GRB201024.12: Global MASTER-Net observations report DATE: 20/10/24 02:56:20 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs V. Lipunov, E. Gorbovskoy, V.Kornilov, N.Tyurina, P.Balanutsa, A.Kuznetsov, F.Balakin, V.Vladimirov, D. Vlasenko, I.Gorbunov, D.Zimnukhov, V.Senik, T.Pogrosheva, D.Kuvshinov, D. Cheryasov (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. Gres, N.M. Budnev, O.Ershova (Irkutsk State University, API), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), V. Yurkov, A. Gabovich, Yu. Sergienko (Blagoveschensk Educational State University) MASTER-SAAO robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in South Africa (South African Astronomical Observatory) was pointed to the Swift GRB201024.12 (trigger No 1001514,08h 23m 47.52s , +03d 22m 37.2s, R=0.05) errorbox 28 sec after notice time and 43 sec after trigger time at 2020-10-24 02:49:43 UT, with upper limit up to 16.2 mag. Observations started at twilight. The observations began at zenith distance = 46 deg. The sun altitude is -12.7 deg. MASTER-IAC robotic telescope located in Spain (IAC Teide Observatory) was pointed to the Swift GRB201024.12 errorbox 146 sec after notice time and 161 sec after trigger time at 2020-10-24 02:51:40 UT, with upper limit up to 16.9 mag. The observations began at zenith distance = 67 deg. The sun altitude is -56.7 deg. The galactic latitude b = 23 deg., longitude l = 221 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1467863 We obtain a following upper limits. Tmid-T0 | Site |Filt.| Expt. | Limit| Comment _________|_____________________|_____|_______|______|________ 49 | MASTER-SAAO | P/ | 10 | 16.0 | 49 | MASTER-SAAO | P\ | 10 | 16.2 | 78 | MASTER-SAAO | P/ | 10 | 15.9 | 78 | MASTER-SAAO | P\ | 10 | 16.1 | 171 | MASTER-IAC | C | 20 | 16.7 | 206 | MASTER-IAC | C | 20 | 16.5 | 242 | MASTER-IAC | C | 30 | 16.9 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited.