TITLE: GCN CIRCULAR NUMBER: 30004 SUBJECT: Fermi trigger No 642538568: Global MASTER-Net observations report DATE: 21/05/12 19:30:25 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-Kislovodsk robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (Lomonosov MSU, Kislovodsk Solar Station of Pulkovo observatory) started inspect of the Fermi GRB210512.79 (trigger No 642538568,09h 44m 43.20s , +14d 10m 48.0s, R=11.56) errorbox 1254 sec after notice time and 1282 sec after trigger time at 2021-05-12 19:17:25 UT, with upper limit up to 18.9 mag. The observations began at zenith distance = 57 deg. The sun altitude is -23.7 deg. The galactic latitude b = 45 deg., longitude l = 221 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1611918 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 1312 | 2021-05-12 19:17:25 | MASTER-Kislovodsk | (09h 37m 37.14s , +13d 58m 52.8s) | C | 60 | 18.1 | 1312 | 2021-05-12 19:17:25 | MASTER-Kislovodsk | (09h 33m 27.39s , +14d 21m 20.8s) | C | 60 | 18.5 | 1393 | 2021-05-12 19:18:46 | MASTER-Kislovodsk | (09h 43m 04.28s , +16d 00m 11.2s) | C | 60 | 18.0 | 1393 | 2021-05-12 19:18:46 | MASTER-Kislovodsk | (09h 38m 50.92s , +16d 22m 42.0s) | C | 60 | 18.8 | 1473 | 2021-05-12 19:20:06 | MASTER-Kislovodsk | (09h 54m 03.27s , +13d 59m 47.5s) | C | 60 | 18.3 | 1473 | 2021-05-12 19:20:06 | MASTER-Kislovodsk | (09h 49m 52.32s , +14d 22m 17.9s) | C | 60 | 18.9 | 1553 | 2021-05-12 19:21:26 | MASTER-Kislovodsk | (09h 49m 20.23s , +12d 00m 42.2s) | C | 60 | 18.1 | 1553 | 2021-05-12 19:21:26 | MASTER-Kislovodsk | (09h 45m 12.67s , +12d 23m 07.2s) | C | 60 | 18.6 | 1633 | 2021-05-12 19:22:46 | MASTER-Kislovodsk | (09h 33m 04.07s , +11d 59m 17.6s) | C | 60 | 17.9 | 1633 | 2021-05-12 19:22:46 | MASTER-Kislovodsk | (09h 28m 58.28s , +12d 21m 35.9s) | C | 60 | 18.5 | 1713 | 2021-05-12 19:24:06 | MASTER-Kislovodsk | (09h 49m 12.38s , +17d 58m 27.6s) | C | 60 | 18.1 | 1713 | 2021-05-12 19:24:06 | MASTER-Kislovodsk | (09h 44m 55.73s , +18d 20m 58.7s) | C | 60 | 18.7 | 1793 | 2021-05-12 19:25:26 | MASTER-Kislovodsk | (09h 59m 42.41s , +15d 59m 07.3s) | C | 60 | 18.0 | 1793 | 2021-05-12 19:25:26 | MASTER-Kislovodsk | (09h 55m 28.40s , +16d 21m 38.8s) | C | 60 | 18.4 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited.