TITLE: GCN CIRCULAR NUMBER: 29756 SUBJECT: Fermi trigger No 639199407: Global MASTER-Net observations report DATE: 21/04/04 04:15:13 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), 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-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) started inspect of the Fermi GRB210404.14 (trigger No 639199407,12h 26m 43.20s , -01d 18m 00.0s, R=10.74) errorbox 275 sec after notice time and 289 sec after trigger time at 2021-04-04 03:28:11 UT, with upper limit up to 19.3 mag. The observations began at zenith distance = 32 deg. The sun altitude is -59.8 deg. The galactic latitude b = 61 deg., longitude l = 292 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1583037 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 319 | 2021-04-04 03:28:11 | MASTER-OAFA | (12h 27m 17.91s , -01d 10m 49.6s) | C | 60 | 19.3 | 1993 | 2021-04-04 03:56:05 | MASTER-OAFA | (12h 27m 09.53s , -01d 09m 17.5s) | C | 60 | 18.5 | 2073 | 2021-04-04 03:57:25 | MASTER-OAFA | (12h 35m 16.58s , -01d 10m 18.4s) | C | 60 | 18.3 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited.