TITLE: GCN CIRCULAR NUMBER: 45311 SUBJECT: IceCube Alert 260807A: Global MASTER-Net observations report DATE: 26/08/07 18:52:39 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru> V.Lipunov, E.Gorbovskoy, A.Kuznetsov, K.Zhirkov, I.Panchenko, N.Tiurina, P.Balanutsa, V.Topolev, D.Vlasenko, G.Antipov, A.Sankovich, Yu.Tselik, Ya.Kechin, V.Senik, A.Chasovnikov, K.Labsina, I. Gorbunov (Lomonosov MSU), O.Gress, N.Budnev (ISU), M. Segura, F. Podesta, R.Podesta, E. Gonzalez (Observatorio Astronomico Felix Aguilar (OAFA), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), A.Sosnovskij (CrAO), A. Gabovich, V.Yurkov (Blagoveschensk Educational StateUniversity), D.Buckley (SAAO), R.Rebolo (The Instituto de Astrofisica de Canarias), L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez (INAOE, Guillermo Haro Astrophysics Observatory) MASTER-Tunka robotic telescope [1] located in Russia (Applied Physics Institute, Irkutsk State University) started inspect of the IceCube Alert 260807A (trigger No 68892416,21h 41m 28.80s , +00d 04m 12.0s, R=2.88) errorbox 45032 sec after notice time and 45086 sec after trigger time at 2026-08-07 18:36:08 UT, with upper limit up to 19.8 mag. The observations began at zenith distance = 53 deg. The sun altitude is -19.4 deg. The galactic latitude b = -37 deg., longitude l = 56 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=3462157 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 45117 | 2026-08-07 18:36:08 | MASTER-Tunka | (21h 40m 12.04s , -00d 17m 44.0s) | C | 60 | 18.9 | 45190 | 2026-08-07 18:37:21 | MASTER-Tunka | (21h 40m 11.54s , -00d 16m 46.4s) | C | 60 | 19.7 | 45264 | 2026-08-07 18:38:36 | MASTER-Tunka | (21h 40m 17.87s , -00d 17m 49.6s) | C | 60 | 19.8 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited. [1] - V.M. Lipunov, V.G. Kornilov, E.S. Gorbovskoy, N.A. Tiurina & A.S.Kuznetsov, 2023, Astronomical Robotic Networks and Operative Multichanel Astrophysics, Lomonosov MSU PRESS, 591pp. http : // www.pereplet.ru/lipunov/625.html View this GCN Circular online at https://gcn.nasa.gov/circulars/45311. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...