GCN Circular 42332

Subject
Fermi GRB 251016B: Global MASTER-Net observations report
Event
GRB 251016B
Date
2025-10-17T20:01:03Z (a day ago)
From
Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>
Via
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  (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 251016B ( Fermi GBM team, GCN 42316Loading...
 
 ) errorbox  64428 sec after notice time and 64463 sec after trigger time at 2025-10-17 17:53:24 UT, with upper limit up to  18.4 mag. The observations began at zenith distance = 75 deg. The sun  altitude  is -38.0 deg. 

The galactic latitude b = 57 deg., longitude l = 131 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=3016439

We obtain a following upper limits.  

Tmid-T0  |      Date Time      |          Site       |             Coord (J2000)          |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________

   64493 | 2025-10-17 17:53:24 |   MASTER-Kislovodsk | (12h 10m 29.71s , +59d 47m 44.4s) |   C |    60 | 17.9 |        
   64493 | 2025-10-17 17:53:24 |   MASTER-Kislovodsk | (12h 02m 34.87s , +60d 07m 45.3s) |   C |    60 | 18.2 |        
   64573 | 2025-10-17 17:54:44 |   MASTER-Kislovodsk | (11h 59m 57.83s , +57d 53m 49.9s) |   C |    60 | 17.7 |        
   64653 | 2025-10-17 17:56:03 |   MASTER-Kislovodsk | (12h 28m 38.77s , +57d 56m 06.7s) |   C |    60 | 17.7 |        
   64653 | 2025-10-17 17:56:03 |   MASTER-Kislovodsk | (12h 21m 10.62s , +58d 16m 11.0s) |   C |    60 | 17.9 |        
   64733 | 2025-10-17 17:57:23 |   MASTER-Kislovodsk | (12h 23m 18.88s , +61d 41m 55.2s) |   C |    60 | 17.6 |        
   64733 | 2025-10-17 17:57:23 |   MASTER-Kislovodsk | (12h 14m 53.21s , +62d 01m 54.8s) |   C |    60 | 18.2 |        
   64976 | 2025-10-17 18:01:26 |   MASTER-Kislovodsk | (12h 32m 54.86s , +60d 10m 17.7s) |   C |    60 | 18.2 |        
   65135 | 2025-10-17 18:04:06 |   MASTER-Kislovodsk | (12h 10m 31.27s , +59d 47m 15.5s) |   C |    60 | 17.9 |        
   65135 | 2025-10-17 18:04:06 |   MASTER-Kislovodsk | (12h 02m 38.29s , +60d 07m 24.6s) |   C |    60 | 18.4 |        
   65216 | 2025-10-17 18:05:26 |   MASTER-Kislovodsk | (12h 00m 00.77s , +57d 53m 08.9s) |   C |    60 | 17.6 |        
   65296 | 2025-10-17 18:06:46 |   MASTER-Kislovodsk | (12h 28m 41.30s , +57d 55m 38.0s) |   C |    60 | 17.6 |        
   65296 | 2025-10-17 18:06:46 |   MASTER-Kislovodsk | (12h 21m 14.36s , +58d 15m 48.0s) |   C |    60 | 18.0 |        
   65781 | 2025-10-17 18:14:51 |   MASTER-Kislovodsk | (12h 23m 20.47s , +61d 42m 21.0s) |   C |    60 | 17.6 |        
   65781 | 2025-10-17 18:14:52 |   MASTER-Kislovodsk | (12h 14m 56.78s , +62d 02m 32.5s) |   C |    60 | 18.1 |        
   66021 | 2025-10-17 18:18:52 |   MASTER-Kislovodsk | (12h 33m 02.17s , +60d 07m 57.4s) |   C |    60 | 18.1 |        
   66181 | 2025-10-17 18:21:31 |   MASTER-Kislovodsk | (12h 10m 40.13s , +59d 48m 37.0s) |   C |    60 | 17.9 |        
   66181 | 2025-10-17 18:21:31 |   MASTER-Kislovodsk | (12h 02m 49.68s , +60d 08m 56.5s) |   C |    60 | 18.3 |        
   66261 | 2025-10-17 18:22:51 |   MASTER-Kislovodsk | (12h 00m 02.22s , +57d 53m 04.0s) |   C |    60 | 17.6 |        
   66341 | 2025-10-17 18:24:11 |   MASTER-Kislovodsk | (12h 28m 46.58s , +57d 54m 54.8s) |   C |    60 | 17.6 |        
   66341 | 2025-10-17 18:24:12 |   MASTER-Kislovodsk | (12h 21m 22.73s , +58d 15m 14.6s) |   C |    60 | 17.9 |        
   66632 | 2025-10-17 18:29:02 |   MASTER-Kislovodsk | (12h 23m 25.23s , +61d 42m 58.9s) |   C |    60 | 17.7 |        
   66632 | 2025-10-17 18:29:02 |   MASTER-Kislovodsk | (12h 15m 03.72s , +62d 03m 15.8s) |   C |    60 | 18.1 |        
   67078 | 2025-10-17 18:36:28 |   MASTER-Kislovodsk | (12h 33m 12.10s , +60d 09m 22.3s) |   C |    60 | 18.1 |        
   67237 | 2025-10-17 18:39:07 |   MASTER-Kislovodsk | (12h 10m 48.06s , +59d 48m 19.7s) |   C |    60 | 17.9 |        
   67237 | 2025-10-17 18:39:08 |   MASTER-Kislovodsk | (12h 02m 58.20s , +60d 08m 43.5s) |   C |    60 | 18.1 |        
   67317 | 2025-10-17 18:40:27 |   MASTER-Kislovodsk | (12h 00m 05.23s , +57d 53m 23.6s) |   C |    60 | 17.6 |        
   67397 | 2025-10-17 18:41:47 |   MASTER-Kislovodsk | (12h 28m 47.12s , +57d 54m 50.5s) |   C |    60 | 17.6 |        
   67397 | 2025-10-17 18:41:47 |   MASTER-Kislovodsk | (12h 21m 23.71s , +58d 15m 15.1s) |   C |    60 | 18.0 |        
   67687 | 2025-10-17 18:46:37 |   MASTER-Kislovodsk | (12h 23m 27.68s , +61d 40m 36.8s) |   C |    60 | 17.6 |        
   67687 | 2025-10-17 18:46:37 |   MASTER-Kislovodsk | (12h 15m 10.60s , +62d 00m 56.4s) |   C |    60 | 18.1 |        
   67926 | 2025-10-17 18:50:37 |   MASTER-Kislovodsk | (12h 33m 18.29s , +60d 07m 34.3s) |   C |    60 | 18.1 |        
   68293 | 2025-10-17 18:56:43 |   MASTER-Kislovodsk | (12h 10m 54.87s , +59d 48m 17.3s) |   C |    60 | 17.9 |        
   68293 | 2025-10-17 18:56:43 |   MASTER-Kislovodsk | (12h 02m 59.73s , +60d 08m 46.1s) |   C |    60 | 18.2 |        
   68373 | 2025-10-17 18:58:03 |   MASTER-Kislovodsk | (12h 00m 24.20s , +57d 53m 11.7s) |   C |    60 | 17.6 |        
   68452 | 2025-10-17 18:59:23 |   MASTER-Kislovodsk | (12h 28m 56.85s , +57d 52m 31.8s) |   C |    60 | 17.6 |        
   68453 | 2025-10-17 18:59:23 |   MASTER-Kislovodsk | (12h 21m 29.31s , +58d 13m 01.5s) |   C |    60 | 17.9 |        
   68753 | 2025-10-17 19:04:23 |   MASTER-Kislovodsk | (12h 23m 37.61s , +61d 41m 55.7s) |   C |    60 | 17.6 |        
   68754 | 2025-10-17 19:04:24 |   MASTER-Kislovodsk | (12h 15m 21.05s , +62d 02m 17.0s) |   C |    60 | 18.1 |        
   68994 | 2025-10-17 19:08:25 |   MASTER-Kislovodsk | (12h 33m 21.64s , +60d 08m 01.0s) |   C |    60 | 18.1 |        
   69157 | 2025-10-17 19:11:08 |   MASTER-Kislovodsk | (12h 10m 49.35s , +59d 47m 14.2s) |   C |    60 | 17.6 |        
   69157 | 2025-10-17 19:11:08 |   MASTER-Kislovodsk | (12h 03m 11.06s , +60d 07m 42.8s) |   C |    60 | 18.2 |        
   69445 | 2025-10-17 19:15:56 |   MASTER-Kislovodsk | (12h 00m 15.93s , +57d 52m 23.4s) |   C |    60 | 17.6 |        
   69525 | 2025-10-17 19:17:15 |   MASTER-Kislovodsk | (12h 28m 54.84s , +57d 54m 20.9s) |   C |    60 | 17.5 |        
   69525 | 2025-10-17 19:17:15 |   MASTER-Kislovodsk | (12h 21m 39.39s , +58d 14m 53.4s) |   C |    60 | 18.1 |        
   69815 | 2025-10-17 19:22:05 |   MASTER-Kislovodsk | (12h 23m 48.31s , +61d 42m 05.7s) |   C |    60 | 17.6 |        
   69815 | 2025-10-17 19:22:05 |   MASTER-Kislovodsk | (12h 15m 32.13s , +62d 02m 32.5s) |   C |    60 | 18.0 |        
   69975 | 2025-10-17 19:24:45 |   MASTER-Kislovodsk | (11h 58m 36.13s , +61d 27m 27.6s) |   C |    60 | 17.9 |        
   70055 | 2025-10-17 19:26:05 |   MASTER-Kislovodsk | (12h 33m 35.77s , +60d 07m 51.8s) |   C |    60 | 17.9 |        
Filter C is a clear (unfiltred) band. 


The observation and reduction will continue. 
The message may be cited.