TITLE: GCN CIRCULAR NUMBER: 29089 SUBJECT: Fermi GRB 201218B: Global MASTER-Net observations report DATE: 20/12/18 19:30:30 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-IAC robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Spain (IAC Teide Observatory) started inspect of the Fermi GRB 201218B ( Fermi GBM team, GCN 29088) errorbox 486 sec after notice time and 588 sec after trigger time at 2020-12-18 19:19:02 UT, with upper limit up to 17.8 mag. Observations started at twilight. The observations began at zenith distance = 70 deg. The sun altitude is -14.8 deg. The galactic latitude b = -4 deg., longitude l = 181 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1506140 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 252 | 2020-12-18 19:13:00 | MASTER- | (05h 45m 58.58s , +27d 19m 06.2s) | C | 50 | 15.6 | 252 | 2020-12-18 19:13:00 | MASTER- | (05h 44m 02.34s , +25d 55m 42.8s) | C | 50 | 15.7 | 317 | 2020-12-18 19:14:01 | MASTER- | (05h 45m 47.34s , +27d 18m 10.9s) | C | 60 | 15.7 | 317 | 2020-12-18 19:14:01 | MASTER- | (05h 44m 18.35s , +25d 55m 09.0s) | C | 60 | 15.8 | 648 | 2020-12-18 19:19:02 | MASTER-IAC | (05h 26m 31.86s , +26d 23m 46.8s) | C | 120 | 17.4 | 798 | 2020-12-18 19:21:21 | MASTER-IAC | (05h 26m 37.93s , +26d 24m 01.9s) | C | 140 | 17.6 | 977 | 2020-12-18 19:24:00 | MASTER-IAC | (05h 26m 35.23s , +26d 25m 12.9s) | C | 180 | 17.8 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited.