TITLE: GCN CIRCULAR NUMBER: 31260 SUBJECT: MAXI GRB211218.04: Global MASTER-Net observations report DATE: 21/12/18 03:51:25 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, T.Pogrosheva, E.Minkina, A.Chasovnikov, V.Topolev, V.Grinshpun, 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 (Irkutsk State University, API), 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) started inspect of the MAXI GRB211218.04 (trigger No 566013095,09h 09m 06.72s , -04d 06m 36.0s, R=1) errorbox 8135 sec after trigger time at 2021-12-18 03:17:09 UT, with upper limit up to 18.3 mag. The observations began at zenith distance = 70 deg. The sun altitude is -32.8 deg. MASTER-IAC robotic telescope located in Spain (IAC Teide Observatory) started inspect of the MAXI GRB211218.04 errorbox 19 sec after notice time and 8221 sec after trigger time at 2021-12-18 03:18:35 UT, with upper limit up to 17.6 mag. The observations began at zenith distance = 36 deg. The sun altitude is -58.4 deg. The galactic latitude b = 28 deg., longitude l = 235 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1818127 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 8226 | 2021-12-18 03:17:09 | MASTER-OAFA | (09h 08m 40.94s , -04d 42m 54.3s) | C | 180 | 17.1 | 8312 | 2021-12-18 03:18:35 | MASTER-IAC | (09h 07m 36.35s , -03d 57m 06.9s) | P- | 180 | 17.3 | 8425 | 2021-12-18 03:20:29 | MASTER-OAFA | (09h 08m 38.08s , -04d 41m 08.9s) | C | 180 | 17.2 | 8512 | 2021-12-18 03:21:55 | MASTER-IAC | (09h 07m 37.32s , -03d 56m 10.9s) | P- | 180 | 17.5 | 8624 | 2021-12-18 03:23:48 | MASTER-OAFA | (09h 08m 38.25s , -04d 42m 58.1s) | C | 180 | 17.4 | 8712 | 2021-12-18 03:25:15 | MASTER-IAC | (09h 07m 41.99s , -03d 57m 13.3s) | P- | 180 | 17.6 | 8824 | 2021-12-18 03:27:07 | MASTER-OAFA | (09h 08m 40.94s , -04d 41m 10.4s) | C | 180 | 17.6 | 9004 | 2021-12-18 03:27:07 | MASTER-OAFA | (09h 08m 40.94s , -04d 41m 10.4s) | C | 540 | 18.3 | Coadd 8912 | 2021-12-18 03:28:35 | MASTER-IAC | (09h 07m 36.10s , -03d 58m 14.8s) | P- | 180 | 17.6 | 9029 | 2021-12-18 03:30:32 | MASTER-OAFA | (09h 08m 36.24s , -04d 42m 01.0s) | C | 180 | 17.6 | 9228 | 2021-12-18 03:33:52 | MASTER-OAFA | (09h 08m 35.95s , -04d 41m 00.3s) | C | 180 | 17.7 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited.