TITLE: GCN CIRCULAR NUMBER: 44428 SUBJECT: EP260430a: Global MASTER-Net observations report DATE: 26/04/30 04:09:48 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), C.Francile, 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-OAFA robotic telescope [1] located in Argentina (OAFA observatory of San Juan National University) was pointed to the EP260430a ( EP Team et al., GCN 44427) errorbox 320 sec after trigger time at 2026-04-30 02:38:07 UT, with upper limit up to 19.0 mag. The observations began at zenith distance = 23 deg. The sun altitude is -59.3 deg. The galactic latitude b = 50 deg., longitude l = 281 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=3281929 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 350 | 2026-04-30 02:38:07 | MASTER-OAFA | (11h 53m 04.26s , -09d 58m 33.8s) | C | 60 | 18.5 | 420 | 2026-04-30 02:38:07 | MASTER-OAFA | (11h 53m 04.26s , -09d 58m 33.8s) | C | 200 | 18.8 | Coadd 426 | 2026-04-30 02:39:13 | MASTER-OAFA | (11h 53m 04.09s , -09d 58m 36.3s) | C | 80 | 15.7 | 1038 | 2026-04-30 02:49:35 | MASTER-OAFA | (11h 53m 02.59s , -09d 59m 04.2s) | C | 60 | 18.5 | 1104 | 2026-04-30 02:50:40 | MASTER-OAFA | (11h 53m 02.42s , -09d 59m 07.3s) | C | 60 | 18.5 | 1164 | 2026-04-30 02:50:40 | MASTER-OAFA | (11h 53m 02.42s , -09d 59m 07.3s) | C | 180 | 18.9 | Coadd 1170 | 2026-04-30 02:51:46 | MASTER-OAFA | (11h 53m 02.26s , -09d 59m 10.5s) | C | 60 | 18.5 | 1236 | 2026-04-30 02:52:52 | MASTER-OAFA | (11h 53m 02.09s , -09d 59m 13.9s) | C | 60 | 18.4 | 1301 | 2026-04-30 02:53:57 | MASTER-OAFA | (11h 53m 01.92s , -09d 59m 17.1s) | C | 60 | 18.5 | 1361 | 2026-04-30 02:53:57 | MASTER-OAFA | (11h 53m 01.92s , -09d 59m 17.1s) | C | 180 | 19.0 | Coadd 1366 | 2026-04-30 02:55:03 | MASTER-OAFA | (11h 53m 01.76s , -09d 59m 20.5s) | C | 60 | 18.5 | 1432 | 2026-04-30 02:56:09 | MASTER-OAFA | (11h 53m 01.60s , -09d 59m 24.0s) | C | 60 | 18.5 | 1498 | 2026-04-30 02:57:14 | MASTER-OAFA | (11h 53m 01.42s , -09d 59m 27.3s) | C | 60 | 18.4 | 1558 | 2026-04-30 02:57:14 | MASTER-OAFA | (11h 53m 01.42s , -09d 59m 27.4s) | C | 180 | 19.0 | Coadd 1564 | 2026-04-30 02:58:20 | MASTER-OAFA | (11h 53m 01.25s , -09d 59m 30.6s) | C | 60 | 18.4 | 1630 | 2026-04-30 02:59:27 | MASTER-OAFA | (11h 53m 01.08s , -09d 59m 34.3s) | C | 60 | 18.5 | 1696 | 2026-04-30 03:00:32 | MASTER-OAFA | (11h 53m 00.91s , -09d 59m 37.8s) | C | 60 | 18.5 | 1761 | 2026-04-30 03:01:38 | MASTER-OAFA | (11h 53m 00.74s , -09d 59m 41.3s) | C | 60 | 18.5 | 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/44428. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...