TITLE: GCN CIRCULAR NUMBER: 38794 SUBJECT: Fermi GRB 250102A: Global MASTER-Net observations report DATE: 25/01/03 14:15:28 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs V.Lipunov, E.Gorbovskoy, N.Tiurina, P.Balanutsa, , D.Vlasenko, I.Panchenko, A.Kuznetsov, G.Antipov, A.Sankovich, A.Sosnovskij, Yu.Tselik, M.Gulyaev, 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. 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 (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (Lomonosov MSU, Kislovodsk Solar Station of Pulkovo observatory) started inspect of the Fermi GRB 250102A ( Fermi GBM team, GCN 38784) errorbox 1044 sec after notice time and 1077 sec after trigger time at 2025-01-02 22:56:02 UT, with upper limit up to 14.5 mag. The observations began at zenith distance = 90 deg. The sun altitude is -61.0 deg. The galactic latitude b = -15 deg., longitude l = 100 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=2731859 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 1168 | 2025-01-02 22:56:02 | MASTER-Kislovodsk | (22h 42m 00.60s , +42d 07m 23.8s) | P- | 180 | 14.5 | 1368 | 2025-01-02 22:59:22 | MASTER-Kislovodsk | (22h 42m 00.83s , +42d 07m 15.1s) | P- | 180 | 14.3 | 1567 | 2025-01-02 23:02:42 | MASTER-Kislovodsk | (22h 41m 56.18s , +42d 08m 00.6s) | P- | 180 | 14.3 | 1767 | 2025-01-02 23:06:02 | MASTER-Kislovodsk | (22h 41m 56.07s , +42d 07m 44.4s) | P- | 180 | 14.1 | 15978 | 2025-01-03 03:03:53 | MASTER-Kislovodsk | (22h 41m 48.44s , +42d 16m 25.5s) | C | 60 | 14.3 | 16138 | 2025-01-03 03:06:33 | MASTER-Kislovodsk | (22h 41m 48.71s , +42d 15m 15.3s) | C | 60 | 14.4 | 16218 | 2025-01-03 03:07:53 | MASTER-Kislovodsk | (22h 41m 44.74s , +42d 16m 45.8s) | C | 60 | 13.9 | 16298 | 2025-01-03 03:09:13 | MASTER-Kislovodsk | (22h 41m 45.28s , +42d 14m 55.4s) | C | 60 | 13.9 | 16378 | 2025-01-03 03:10:33 | MASTER-Kislovodsk | (22h 41m 49.42s , +42d 16m 49.3s) | C | 60 | 14.3 | 16458 | 2025-01-03 03:11:53 | MASTER-Kislovodsk | (22h 41m 42.71s , +42d 15m 49.3s) | C | 60 | 14.1 | 16861 | 2025-01-03 03:18:35 | MASTER-Kislovodsk | (22h 41m 43.84s , +42d 17m 07.6s) | C | 60 | 14.5 | 16940 | 2025-01-03 03:19:55 | MASTER-Kislovodsk | (22h 41m 49.01s , +42d 16m 04.5s) | C | 60 | 14.4 | 17624 | 2025-01-03 03:31:19 | MASTER-Kislovodsk | (22h 41m 48.01s , +42d 15m 31.1s) | C | 60 | 14.5 | 17704 | 2025-01-03 03:32:38 | MASTER-Kislovodsk | (22h 41m 51.23s , +42d 17m 11.4s) | C | 60 | 14.4 | 17784 | 2025-01-03 03:33:58 | MASTER-Kislovodsk | (22h 41m 41.00s , +42d 16m 19.6s) | C | 60 | 12.4 | 17943 | 2025-01-03 03:36:38 | MASTER-Kislovodsk | (22h 41m 53.78s , +42d 16m 10.6s) | C | 60 | 13.7 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited.