TITLE: GCN CIRCULAR NUMBER: 42853 SUBJECT: Fermi GRB 251127A: Global MASTER-Net observations report DATE: 25/11/27 03:30:35 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-Kislovodsk robotic telescope [1] located in Russia (Lomonosov MSU, Kislovodsk Solar Station of Pulkovo observatory) started inspect of the Fermi GRB 251127A ( Fermi GBM team, GCN 42852) errorbox 26 sec after notice time and 61 sec after trigger time at 2025-11-27 03:18:44 UT, with upper limit up to 16.6 mag. Observations started at twilight. The observations began at zenith distance = 14 deg. The sun altitude is -10.6 deg. The galactic latitude b = 58 deg., longitude l = 199 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=3052815 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 67 | 2025-11-27 03:18:44 | MASTER-Kislovodsk | (10h 26m 49.07s , +29d 21m 07.8s) | C | 10 | 15.7 | 67 | 2025-11-27 03:18:44 | MASTER-Kislovodsk | (10h 21m 41.55s , +29d 42m 18.9s) | C | 10 | 14.2 | 96 | 2025-11-27 03:19:13 | MASTER-Kislovodsk | (10h 26m 49.14s , +29d 21m 07.1s) | C | 10 | 15.7 | 96 | 2025-11-27 03:19:14 | MASTER-Kislovodsk | (10h 21m 41.27s , +29d 42m 13.3s) | C | 10 | 14.1 | 144 | 2025-11-27 03:19:52 | MASTER-Kislovodsk | (10h 28m 11.83s , +32d 30m 38.8s) | C | 30 | 16.6 | 144 | 2025-11-27 03:19:52 | MASTER-Kislovodsk | (10h 22m 52.53s , +32d 52m 02.7s) | C | 30 | 15.4 | 194 | 2025-11-27 03:20:42 | MASTER-Kislovodsk | (10h 22m 52.49s , +32d 52m 02.0s) | C | 30 | 15.2 | 194 | 2025-11-27 03:20:42 | MASTER-Kislovodsk | (10h 28m 11.82s , +32d 30m 38.3s) | C | 30 | 16.4 | 249 | 2025-11-27 03:21:31 | MASTER-Kislovodsk | (10h 22m 52.28s , +32d 51m 59.6s) | C | 40 | 15.4 | 249 | 2025-11-27 03:21:31 | MASTER-Kislovodsk | (10h 28m 11.77s , +32d 30m 37.9s) | C | 40 | 16.6 | 314 | 2025-11-27 03:22:31 | MASTER-Kislovodsk | (10h 28m 11.71s , +32d 30m 37.2s) | C | 50 | 16.4 | 314 | 2025-11-27 03:22:31 | MASTER-Kislovodsk | (10h 22m 52.22s , +32d 51m 59.0s) | C | 50 | 15.1 | 394 | 2025-11-27 03:23:41 | MASTER-Kislovodsk | (10h 22m 51.99s , +32d 51m 57.2s) | C | 70 | 15.1 | 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/42853. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...