TITLE: GCN CIRCULAR NUMBER: 26523 SUBJECT: Fermi trigger No 598543714: Global MASTER-Net observations report DATE: 19/12/20 22:32:21 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), H.Levato (Instituto de Ciencias Astronomicas, de la Tierra y del Espacio ICATE), 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 GRB191220.59 (trigger No 598543714,15h 15m 24.00s , -56d 31m 01.2s, R=35.67) errorbox 25598 sec after trigger time at 2019-12-20 21:15:08 UT, with upper limit up to 19.0 mag. The observations began at zenith distance = 57 deg. The sun altitude is -31.3 deg. The galactic latitude b = 1 deg., longitude l = 322 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1233652 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 25689 | 2019-12-20 21:15:08 | MASTER-SAAO | (09h 47m 50.47s , -67d 53m 20.7s) | C | 180 | 19.0 | 26343 | 2019-12-20 21:26:02 | MASTER-SAAO | (09h 47m 52.63s , -67d 54m 17.7s) | C | 180 | 19.0 | 26560 | 2019-12-20 21:29:38 | MASTER-SAAO | (10h 09m 10.02s , -67d 53m 41.5s) | C | 180 | 18.6 | 27213 | 2019-12-20 21:40:32 | MASTER-SAAO | (10h 09m 06.15s , -67d 53m 04.0s) | C | 180 | 18.8 | 27921 | 2019-12-20 21:52:20 | MASTER-SAAO | (10h 00m 31.10s , -65d 53m 45.9s) | C | 180 | 18.6 | 28579 | 2019-12-20 22:03:18 | MASTER-SAAO | (10h 00m 33.37s , -65d 52m 09.1s) | C | 180 | 18.6 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited.