TITLE: GCN CIRCULAR NUMBER: 33311 SUBJECT: Fermi GRB 230209B: Global MASTER-Net observations report DATE: 23/02/09 23:30:19 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 230209B ( Fermi GBM team, GCN 33310) errorbox 78 sec after notice time and 112 sec after trigger time at 2023-02-09 22:34:29 UT, with upper limit up to 17.6 mag. The observations began at zenith distance = 74 deg. The sun altitude is -43.2 deg. The galactic latitude b = -2 deg., longitude l = 185 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=2197905 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 123 | 2023-02-09 22:34:29 | MASTER-SAAO | (05h 48m 38.85s , +23d 25m 41.1s) | C | 20 | 17.3 | 123 | 2023-02-09 22:34:29 | MASTER-SAAO | (05h 47m 42.98s , +23d 26m 01.2s) | C | 20 | 16.6 | 167 | 2023-02-09 22:35:09 | MASTER-SAAO | (05h 48m 43.58s , +23d 26m 01.0s) | C | 30 | 17.5 | 167 | 2023-02-09 22:35:09 | MASTER-SAAO | (05h 47m 47.64s , +23d 26m 21.7s) | C | 30 | 16.9 | 233 | 2023-02-09 22:36:09 | MASTER-SAAO | (05h 48m 41.95s , +23d 27m 14.2s) | C | 40 | 17.6 | 233 | 2023-02-09 22:36:10 | MASTER-SAAO | (05h 47m 46.01s , +23d 27m 36.0s) | C | 40 | 17.0 | 298 | 2023-02-09 22:37:09 | MASTER-SAAO | (05h 48m 42.43s , +23d 25m 55.7s) | C | 50 | 17.6 | 298 | 2023-02-09 22:37:09 | MASTER-SAAO | (05h 47m 46.50s , +23d 26m 18.0s) | C | 50 | 17.0 | 389 | 2023-02-09 22:38:30 | MASTER-SAAO | (05h 48m 45.87s , +23d 27m 28.8s) | C | 70 | 17.5 | 389 | 2023-02-09 22:38:30 | MASTER-SAAO | (05h 47m 49.96s , +23d 27m 51.9s) | C | 70 | 16.9 | 649 | 2023-02-09 22:42:26 | MASTER-SAAO | (05h 48m 40.23s , +23d 31m 32.5s) | C | 120 | 17.1 | 649 | 2023-02-09 22:42:26 | MASTER-SAAO | (05h 47m 43.59s , +23d 32m 07.7s) | C | 120 | 16.5 | 810 | 2023-02-09 22:44:56 | MASTER-SAAO | (05h 48m 36.07s , +23d 30m 39.6s) | C | 140 | 16.9 | 810 | 2023-02-09 22:44:56 | MASTER-SAAO | (05h 47m 39.45s , +23d 31m 15.3s) | C | 140 | 16.2 | 1000 | 2023-02-09 22:47:47 | MASTER-SAAO | (05h 48m 43.26s , +23d 30m 46.1s) | C | 180 | 17.1 | 1000 | 2023-02-09 22:47:47 | MASTER-SAAO | (05h 47m 46.69s , +23d 31m 22.6s) | C | 180 | 16.2 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited.