TITLE: GCN CIRCULAR NUMBER: 30266 SUBJECT: Fermi trigger No 645857659: Global MASTER-Net observations report DATE: 21/06/20 05:30:10 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-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 Fermi GRB210620.20 (trigger No 645857659,19h 12m 12.00s , +45d 37m 48.0s, R=6.45) errorbox 253 sec after notice time and 297 sec after trigger time at 2021-06-20 04:59:11 UT, with upper limit up to 17.6 mag. The observations began at zenith distance = 76 deg. The sun altitude is -80.9 deg. MASTER-IAC robotic telescope located in Spain (IAC Teide Observatory) started inspect of the Fermi GRB210620.20 errorbox 299 sec after notice time and 343 sec after trigger time at 2021-06-20 04:59:57 UT, with upper limit up to 18.8 mag. Observations started at twilight. The observations began at zenith distance = 35 deg. The sun altitude is -13.4 deg. The galactic latitude b = 15 deg., longitude l = 77 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1640801 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 328 | 2021-06-20 04:59:11 | MASTER-OAFA | (19h 10m 23.35s , +44d 10m 50.2s) | C | 60 | 17.6 | 373 | 2021-06-20 04:59:57 | MASTER-IAC | (19h 19m 29.47s , +46d 42m 56.0s) | C | 60 | 18.6 | 373 | 2021-06-20 04:59:57 | MASTER-IAC | (19h 07m 33.07s , +46d 48m 53.7s) | C | 60 | 18.5 | 407 | 2021-06-20 05:00:31 | MASTER-OAFA | (19h 21m 41.57s , +44d 11m 39.3s) | C | 60 | 17.2 | 453 | 2021-06-20 05:01:17 | MASTER-IAC | (19h 16m 43.09s , +48d 37m 26.4s) | C | 60 | 18.8 | 453 | 2021-06-20 05:01:17 | MASTER-IAC | (19h 04m 20.07s , +48d 43m 25.0s) | C | 60 | 18.4 | 495 | 2021-06-20 05:01:59 | MASTER-OAFA | (19h 15m 39.40s , +42d 15m 51.7s) | C | 60 | 17.2 | 533 | 2021-06-20 05:02:37 | MASTER-IAC | (19h 41m 43.01s , +46d 44m 10.7s) | C | 60 | 18.5 | 533 | 2021-06-20 05:02:37 | MASTER-IAC | (19h 29m 46.16s , +46d 50m 07.1s) | C | 60 | 18.3 | 575 | 2021-06-20 05:03:19 | MASTER-OAFA | (19h 26m 40.61s , +42d 16m 03.0s) | C | 60 | 17.2 | 613 | 2021-06-20 05:03:57 | MASTER-IAC | (19h 39m 40.25s , +48d 36m 51.5s) | C | 60 | 18.6 | 613 | 2021-06-20 05:03:57 | MASTER-IAC | (19h 27m 17.18s , +48d 42m 49.0s) | C | 60 | 18.4 | 655 | 2021-06-20 05:04:38 | MASTER-OAFA | (18h 49m 00.22s , +44d 10m 41.9s) | C | 60 | 17.4 | 694 | 2021-06-20 05:05:18 | MASTER-IAC | (19h 07m 35.69s , +42d 56m 56.6s) | C | 60 | 18.7 | 694 | 2021-06-20 05:05:18 | MASTER-IAC | (18h 56m 24.32s , +43d 02m 50.6s) | C | 60 | 18.3 | 734 | 2021-06-20 05:05:58 | MASTER-OAFA | (19h 00m 21.36s , +44d 12m 02.1s) | C | 60 | 17.6 | 774 | 2021-06-20 05:06:38 | MASTER-IAC | (19h 14m 51.43s , +50d 31m 58.7s) | C | 60 | 18.5 | 774 | 2021-06-20 05:06:38 | MASTER-IAC | (19h 01m 58.23s , +50d 37m 58.2s) | C | 60 | 18.0 | 814 | 2021-06-20 05:07:18 | MASTER-OAFA | (19h 31m 50.64s , +44d 11m 34.0s) | C | 60 | 17.2 | 854 | 2021-06-20 05:07:58 | MASTER-IAC | (19h 38m 46.49s , +50d 32m 32.0s) | C | 60 | 18.4 | 854 | 2021-06-20 05:07:58 | MASTER-IAC | (19h 25m 53.27s , +50d 38m 30.2s) | C | 60 | 18.3 | 894 | 2021-06-20 05:08:37 | MASTER-OAFA | (19h 43m 14.59s , +44d 10m 20.5s) | C | 60 | 16.9 | 934 | 2021-06-20 05:09:18 | MASTER-IAC | (18h 57m 23.73s , +46d 44m 24.9s) | C | 60 | 18.4 | 1172 | 2021-06-20 05:13:16 | MASTER-OAFA | (19h 36m 29.03s , +42d 17m 13.0s) | C | 60 | 17.0 | 1457 | 2021-06-20 05:18:00 | MASTER-OAFA | (19h 47m 27.90s , +42d 16m 50.6s) | C | 60 | 16.9 | 1536 | 2021-06-20 05:19:20 | MASTER-OAFA | (19h 10m 24.10s , +44d 10m 51.0s) | C | 60 | 17.5 | 1616 | 2021-06-20 05:20:39 | MASTER-OAFA | (19h 21m 41.97s , +44d 11m 37.7s) | C | 60 | 17.2 | 1696 | 2021-06-20 05:21:59 | MASTER-OAFA | (19h 15m 44.93s , +42d 16m 49.4s) | C | 60 | 17.3 | 1775 | 2021-06-20 05:23:19 | MASTER-OAFA | (19h 26m 34.68s , +42d 15m 35.6s) | C | 60 | 17.1 | 1855 | 2021-06-20 05:24:39 | MASTER-OAFA | (18h 49m 02.06s , +44d 10m 36.1s) | C | 60 | 17.4 | 1934 | 2021-06-20 05:25:58 | MASTER-OAFA | (19h 00m 17.50s , +44d 12m 10.0s) | C | 60 | 17.5 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited.