TITLE: GCN CIRCULAR NUMBER: 33362 SUBJECT: Fermi GRB 230220B: Global MASTER-Net observations report DATE: 23/02/21 18:30:37 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs V. Lipunov, V.Kornilov, E.Gorbovskoy, K.Zhirkov, N.Tyurina, P.Balanutsa, A.Kuznetsov, D. Vlasenko, G.Antipov, D.Zimnukhov, V.Senik, E.Minkina, A.Chasovnikov, V.Topolev, D.Kuvshinov, D.Cheryasov, Ya.Kechin (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 (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), A. Gabovich, V.Yurkov (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) started inspect of the Fermi GRB 230220B ( Fermi GBM team, GCN 33357) errorbox 74491 sec after notice time and 74524 sec after trigger time at 2023-02-21 18:07:10 UT, with upper limit up to 17.9 mag. Observations started at twilight. The observations began at zenith distance = 70 deg. The sun altitude is -9.8 deg. The galactic latitude b = -26 deg., longitude l = 155 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=2200481 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 74555 | 2023-02-21 18:07:10 | MASTER-SAAO | (03h 03m 16.78s , +27d 44m 15.6s) | C | 60 | 13.8 | 74688 | 2023-02-21 18:09:23 | MASTER-SAAO | (03h 12m 13.77s , +27d 45m 15.6s) | C | 60 | 16.3 | 74688 | 2023-02-21 18:09:23 | MASTER-SAAO | (03h 13m 10.41s , +27d 45m 00.7s) | C | 60 | 16.2 | 74778 | 2023-02-21 18:10:53 | MASTER-SAAO | (03h 03m 18.99s , +27d 44m 23.4s) | C | 60 | 16.3 | 74778 | 2023-02-21 18:10:53 | MASTER-SAAO | (03h 04m 15.47s , +27d 44m 08.6s) | C | 60 | 16.2 | 74857 | 2023-02-21 18:12:13 | MASTER-SAAO | (02h 29m 06.25s , +27d 44m 20.1s) | C | 60 | 15.4 | 74858 | 2023-02-21 18:12:13 | MASTER-SAAO | (02h 30m 02.34s , +27d 44m 03.8s) | C | 60 | 15.6 | 74948 | 2023-02-21 18:13:44 | MASTER-SAAO | (02h 38m 02.65s , +27d 45m 45.2s) | C | 60 | 16.0 | 74948 | 2023-02-21 18:13:44 | MASTER-SAAO | (02h 38m 58.83s , +27d 45m 28.5s) | C | 60 | 16.2 | 75028 | 2023-02-21 18:15:04 | MASTER-SAAO | (02h 46m 11.46s , +27d 45m 26.4s) | C | 60 | 16.5 | 75028 | 2023-02-21 18:15:04 | MASTER-SAAO | (02h 47m 07.74s , +27d 45m 09.6s) | C | 60 | 16.6 | 75120 | 2023-02-21 18:16:35 | MASTER-SAAO | (02h 55m 05.64s , +27d 44m 41.1s) | C | 60 | 16.9 | 75120 | 2023-02-21 18:16:35 | MASTER-SAAO | (02h 56m 02.04s , +27d 44m 24.1s) | C | 60 | 16.9 | 75211 | 2023-02-21 18:18:06 | MASTER-SAAO | (03h 00m 15.42s , +25d 50m 37.4s) | C | 60 | 17.3 | 75211 | 2023-02-21 18:18:06 | MASTER-SAAO | (03h 01m 11.01s , +25d 50m 20.3s) | C | 60 | 17.4 | 75291 | 2023-02-21 18:19:26 | MASTER-SAAO | (03h 09m 01.02s , +25d 49m 35.2s) | C | 60 | 17.5 | 75291 | 2023-02-21 18:19:26 | MASTER-SAAO | (03h 09m 56.69s , +25d 49m 18.2s) | C | 60 | 17.6 | 75381 | 2023-02-21 18:20:57 | MASTER-SAAO | (02h 27m 31.68s , +25d 51m 45.2s) | C | 60 | 16.8 | 75381 | 2023-02-21 18:20:57 | MASTER-SAAO | (02h 26m 36.42s , +25d 52m 03.5s) | C | 60 | 16.6 | 75461 | 2023-02-21 18:22:16 | MASTER-SAAO | (02h 35m 26.12s , +25d 50m 31.7s) | C | 60 | 17.0 | 75461 | 2023-02-21 18:22:16 | MASTER-SAAO | (02h 36m 21.46s , +25d 50m 13.3s) | C | 60 | 17.3 | 75552 | 2023-02-21 18:23:47 | MASTER-SAAO | (02h 49m 12.43s , +29d 39m 01.5s) | C | 60 | 17.4 | 75552 | 2023-02-21 18:23:47 | MASTER-SAAO | (02h 50m 09.66s , +29d 38m 42.6s) | C | 60 | 17.6 | 75631 | 2023-02-21 18:25:07 | MASTER-SAAO | (02h 58m 22.85s , +29d 39m 58.7s) | C | 60 | 17.6 | 75631 | 2023-02-21 18:25:07 | MASTER-SAAO | (02h 59m 20.21s , +29d 39m 39.5s) | C | 60 | 17.9 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited.