TITLE: GCN CIRCULAR NUMBER: 27706 SUBJECT: Swift GRB 200509A: Global MASTER-Net observations report DATE: 20/05/09 19:38:22 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 200509A ( E. Troja et al., GCN 27701) errorbox 42927 sec after notice time and 42979 sec after trigger time at 2020-05-09 18:43:37 UT, with upper limit up to 19.1 mag. The observations began at zenith distance = 56 deg. The sun altitude is -36.1 deg. The galactic latitude b = 10 deg., longitude l = 224 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1352906 We obtain a following upper limits. Tmid-T0 | Site |Filt.| Expt. | Limit| Comment _________|_____________________|_____|_______|______|________ 43070 | MASTER-SAAO | C | 180 | 19.1 | 43070 | MASTER-SAAO | C | 180 | 19.0 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited.