TITLE: GCN CIRCULAR NUMBER: 27512 SUBJECT: Swift GRB 200409A: Global MASTER-Net observations report DATE: 20/04/09 17:32:31 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), H.Levato (Instituto de Ciencias Astronomicas, de la Tierra y del Espacio ICATE), 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 GRB 200409A ( J.D. Gropp et al., GCN 27509) errorbox 49717 sec after notice time and 49742 sec after trigger time at 2020-04-09 17:09:01 UT, with upper limit up to 19.1 mag. Observations started at twilight. The observations began at zenith distance = 44 deg. The sun altitude is -10.2 deg. The galactic latitude b = -47 deg., longitude l = 259 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1333122 We obtain a following upper limits. Tmid-T0 | Site |Filt.| Expt. | Limit| Comment _________|_____________________|_____|_______|______|________ 49832 | MASTER-SAAO | C | 180 | 19.1 | 49834 | MASTER-SAAO | C | 180 | 19.0 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited.