TITLE: GCN CIRCULAR NUMBER: 45662 SUBJECT: EP Alert 260920.66: Global MASTER-Net observations report DATE: 26/09/20 19:36:47 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs O.Gress, N.Budnev(ISU) 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 (Lomonosov MSU) D.Buckley (SAAO), A. Gabovich, V.Yurkov (Blagoveschensk Educational StateUniversity) A.Sosnovskij (Lomonosov MSU) A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory) L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez (INAOE, Guillermo Haro Astrophysics Observatory) R.Rebolo (The Instituto de Astrofisica de Canarias) M. Segura, F. Podesta, R.Podesta, E. Gonzalez (Observatorio Astronomico Felix Aguilar (OAFA) MASTER-Tunka robotic telescope [1] located in Russia (Applied Physics Institute, Irkutsk State University) was pointed to the EP Alert 260920.66 (trigger No 1709318523,04h 40m 57.84s , +44d 32m 16.8s, R=0.0502579) errorbox 10954 sec after notice time and 11287 sec after trigger time at 2026-09-20 19:01:11 UT, with upper limit up to 18.8 mag. The observations began at zenith distance = 28 deg. The sun altitude is -31.3 deg. The galactic latitude b = -1 deg., longitude l = 160 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=3507985 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 11317 | 2026-09-20 19:01:11 | MASTER-Tunka | (04h 38m 12.95s , +44d 20m 59.7s) | C | 60 | 18.0 | 11317 | 2026-09-20 19:01:11 | MASTER-Tunka | (04h 38m 48.51s , +44d 15m 32.6s) | C | 60 | 18.8 | 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