TITLE: GCN CIRCULAR NUMBER: 29272 SUBJECT: Fermi trigger No 631602681: Global MASTER-Net observations report DATE: 21/01/06 19:15:09 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-SAAO robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in South Africa (South African Astronomical Observatory) started inspect of the Fermi GRB210106.22 (trigger No 631602681,22h 33m 48.00s , +09d 00m 00.0s, R=21.01) errorbox 49110 sec after notice time and 49171 sec after trigger time at 2021-01-06 18:50:47 UT, with upper limit up to 19.1 mag. Observations started at twilight. The observations began at zenith distance = 61 deg. The sun altitude is -12.0 deg. The galactic latitude b = -41 deg., longitude l = 76 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1520294 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 49261 | 2021-01-06 18:50:47 | MASTER-SAAO | (23h 16m 37.31s , -07d 55m 40.8s) | C | 180 | 18.5 | 49461 | 2021-01-06 18:54:07 | MASTER-SAAO | (23h 16m 42.96s , -07d 55m 25.1s) | C | 180 | 18.9 | 49661 | 2021-01-06 18:57:26 | MASTER-SAAO | (23h 16m 39.79s , -07d 53m 59.2s) | C | 180 | 18.9 | 49860 | 2021-01-06 19:00:46 | MASTER-SAAO | (23h 17m 39.97s , -07d 49m 41.9s) | C | 180 | 19.1 | 50060 | 2021-01-06 19:04:06 | MASTER-SAAO | (23h 17m 43.45s , -07d 48m 01.6s) | C | 180 | 19.0 | 50260 | 2021-01-06 19:07:26 | MASTER-SAAO | (23h 17m 36.98s , -07d 49m 04.2s) | C | 180 | 19.0 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited.