TITLE: GCN CIRCULAR NUMBER: 32061 SUBJECT: Swift GRB 220518A: Global MASTER-Net observations report DATE: 22/05/18 08:36:38 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-OAFA robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Argentina (OAFA observatory of San Juan National University) was pointed to the Swift GRB 220518A ( J.D. Gropp et al., GCN 32060) errorbox 6501 sec after notice time and 6534 sec after trigger time at 2022-05-18 08:08:15 UT, with upper limit up to 15.6 mag. The observations began at zenith distance = 87 deg. The sun altitude is -40.1 deg. The galactic latitude b = -51 deg., longitude l = 256 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1977169 We obtain a following upper limits. Tmid-T0 | Site |Filt.| Expt. | Limit| Comment _________|_____________________|_____|_______|______|________ 6565 | MASTER-OAFA | C | 60 | 14.3 | 7687 | MASTER-OAFA | C | 180 | 15.3 | 7947 | MASTER-OAFA | C | 60 | 15.6 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited.