TITLE: GCN CIRCULAR NUMBER: 30152 SUBJECT: IceCube Alert 210608.15: Global MASTER-Net observations report DATE: 21/06/08 06:13:08 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 IceCube Alert 210608.15 (trigger No 69917294,22h 28m 04.32s , +18d 38m 49.2s, R=1.31) errorbox 6843 sec after notice time and 6874 sec after trigger time at 2021-06-08 05:35:35 UT, with upper limit up to 18.0 mag. The observations began at zenith distance = 78 deg. The sun altitude is -74.0 deg. The galactic latitude b = -33 deg., longitude l = 83 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1631004 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 6905 | 2021-06-08 05:35:35 | MASTER-OAFA | (22h 28m 56.85s , +15d 35m 59.9s) | C | 60 | 15.4 | 6984 | 2021-06-08 05:36:55 | MASTER-OAFA | (22h 18m 32.02s , +17d 30m 17.3s) | C | 60 | 16.7 | 7469 | 2021-06-08 05:45:00 | MASTER-OAFA | (22h 18m 01.88s , +19d 24m 09.8s) | C | 60 | 17.1 | 7549 | 2021-06-08 05:46:19 | MASTER-OAFA | (22h 26m 29.43s , +19d 25m 15.7s) | C | 60 | 16.4 | 7913 | 2021-06-08 05:52:23 | MASTER-OAFA | (22h 28m 50.14s , +15d 36m 44.2s) | C | 60 | 17.2 | 7992 | 2021-06-08 05:53:43 | MASTER-OAFA | (22h 18m 28.78s , +17d 31m 56.4s) | C | 60 | 17.8 | 8072 | 2021-06-08 05:55:02 | MASTER-OAFA | (22h 27m 00.31s , +17d 30m 50.7s) | C | 60 | 17.5 | 8560 | 2021-06-08 06:03:11 | MASTER-OAFA | (22h 17m 57.42s , +19d 24m 07.1s) | C | 60 | 18.0 | 8640 | 2021-06-08 06:04:30 | MASTER-OAFA | (22h 26m 31.07s , +19d 25m 39.3s) | C | 60 | 17.9 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited.