TITLE: GCN CIRCULAR NUMBER: 45656 SUBJECT: EP260917a: Global MASTER-Net observations report DATE: 26/09/20 10:09:33 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs M. Segura, F. Podesta, R.Podesta, E. Gonzalez (Observatorio Astronomico Felix Aguilar (OAFA) 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) O.Gress, N.Budnev(ISU) MASTER-Tavrida robotic telescope [1] located in Russia (Lomonosov MSU, SAI Crimea astronomical station) was pointed to the EP260917a ( EP Team at NAOC/CAS et al., GCN 45621) errorbox 5669 sec after notice time and 1 days 24067 sec after trigger time at 2026-09-19 17:19:38 UT, with upper limit up to 17.3 mag. Observations started at twilight. The observations began at zenith distance = 50 deg. The sun altitude is -17.0 deg. MASTER-OAFA robotic telescope located in Argentina (OAFA observatory of San Juan National University) was pointed to the EP260917a errorbox 35682 sec after notice time and 1 days 54080 sec after trigger time at 2026-09-20 01:39:51 UT, with upper limit up to 18.2 mag. The observations began at zenith distance = 46 deg. The sun altitude is -39.7 deg. The galactic latitude b = -39 deg., longitude l = 73 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=3507281 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 110498 | 2026-09-19 17:19:38 | MASTER-Tavrida | (22h 17m 15.77s , +10d 02m 03.4s) | C | 60 | 17.2 | 110498 | 2026-09-19 17:19:38 | MASTER-Tavrida | (22h 17m 15.04s , +10d 01m 19.4s) | C | 60 | 17.3 | 140511 | 2026-09-20 01:39:51 | MASTER-OAFA | (22h 19m 36.59s , +09d 24m 16.7s) | C | 60 | 17.1 | 140571 | 2026-09-20 01:39:51 | MASTER-OAFA | (22h 19m 36.59s , +09d 24m 16.7s) | C | 180 | 18.0 | Coadd 140587 | 2026-09-20 01:41:07 | MASTER-OAFA | (22h 19m 43.55s , +09d 23m 15.0s) | C | 60 | 17.6 | 140663 | 2026-09-20 01:42:24 | MASTER-OAFA | (22h 19m 35.65s , +09d 22m 13.0s) | C | 60 | 17.7 | 140742 | 2026-09-20 01:43:42 | MASTER-OAFA | (22h 19m 41.48s , +09d 22m 36.9s) | C | 60 | 17.8 | 140802 | 2026-09-20 01:43:42 | MASTER-OAFA | (22h 19m 41.47s , +09d 22m 36.9s) | C | 180 | 18.0 | Coadd 140816 | 2026-09-20 01:44:57 | MASTER-OAFA | (22h 19m 38.97s , +09d 23m 59.5s) | C | 60 | 17.7 | 140892 | 2026-09-20 01:46:12 | MASTER-OAFA | (22h 19m 38.70s , +09d 22m 06.0s) | C | 60 | 17.0 | 143523 | 2026-09-20 02:30:03 | MASTER-OAFA | (22h 19m 26.85s , +09d 21m 04.0s) | C | 60 | 17.6 | 143583 | 2026-09-20 02:30:03 | MASTER-OAFA | (22h 19m 26.85s , +09d 21m 04.0s) | C | 180 | 18.2 | Coadd 143600 | 2026-09-20 02:31:20 | MASTER-OAFA | (22h 19m 19.87s , +09d 20m 22.2s) | C | 60 | 18.1 | 143677 | 2026-09-20 02:32:37 | MASTER-OAFA | (22h 19m 20.46s , +09d 21m 16.6s) | C | 60 | 17.8 | 143753 | 2026-09-20 02:33:53 | MASTER-OAFA | (22h 19m 25.80s , +09d 20m 11.7s) | C | 60 | 18.0 | 143813 | 2026-09-20 02:33:53 | MASTER-OAFA | (22h 19m 25.80s , +09d 20m 11.7s) | C | 180 | 18.2 | Coadd 143829 | 2026-09-20 02:35:09 | MASTER-OAFA | (22h 19m 20.27s , +09d 19m 05.9s) | C | 60 | 17.8 | 143906 | 2026-09-20 02:36:27 | MASTER-OAFA | (22h 19m 25.24s , +09d 19m 13.2s) | C | 60 | 17.5 | 143984 | 2026-09-20 02:37:44 | MASTER-OAFA | (22h 19m 21.46s , +09d 20m 46.7s) | C | 60 | 17.9 | 144044 | 2026-09-20 02:37:44 | MASTER-OAFA | (22h 19m 21.46s , +09d 20m 46.7s) | C | 180 | 18.0 | Coadd 144058 | 2026-09-20 02:38:58 | MASTER-OAFA | (22h 19m 21.04s , +09d 19m 10.4s) | C | 60 | 16.9 | 144133 | 2026-09-20 02:40:13 | MASTER-OAFA | (22h 19m 24.13s , +09d 20m 35.2s) | C | 60 | 17.6 | 144210 | 2026-09-20 02:41:30 | MASTER-OAFA | (22h 19m 17.16s , +09d 19m 35.9s) | C | 60 | 17.5 | 144270 | 2026-09-20 02:41:30 | MASTER-OAFA | (22h 19m 17.15s , +09d 19m 35.9s) | C | 180 | 17.5 | Coadd 144287 | 2026-09-20 02:42:48 | MASTER-OAFA | (22h 19m 16.67s , +09d 20m 29.3s) | C | 60 | 17.2 | 144362 | 2026-09-20 02:44:02 | MASTER-OAFA | (22h 19m 22.45s , +09d 19m 24.6s) | C | 60 | 15.8 | 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