GCN Circular 42114

Subject
Fermi trigger No 781367244: Global MASTER-Net observations report
Date
2025-10-05T18:15:34Z (3 days 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-SAAO robotic telescope  (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L)  located in South Africa (South African Astronomical Observatory) started inspect of the Fermi GRB251005.60 (trigger No 781367244,19h 54m 28.80s , -08d 55m 12.0s, R=6.5) errorbox  11063 sec after notice time and 11097 sec after trigger time at 2025-10-05 17:32:16 UT, with upper limit up to  17.8 mag. Observations started at twilight.  The observations began at zenith distance = 23 deg. The sun  altitude  is -11.1 deg. 

The galactic latitude b = -19 deg., longitude l = 32 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=3007732

We obtain a following upper limits.  

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

   11127 | 2025-10-05 17:32:16 |         MASTER-SAAO | (19h 53m 05.61s , -08d 35m 40.3s) |   C |    60 | 17.2 |        
   11127 | 2025-10-05 17:32:16 |         MASTER-SAAO | (19h 51m 12.16s , -08d 20m 30.0s) |   C |    60 | 17.6 |        
   11226 | 2025-10-05 17:33:55 |         MASTER-SAAO | (20h 01m 01.07s , -08d 37m 00.8s) |   C |    60 | 17.4 |        
   11226 | 2025-10-05 17:33:55 |         MASTER-SAAO | (19h 59m 07.53s , -08d 21m 50.9s) |   C |    60 | 17.8 |        
   11424 | 2025-10-05 17:37:13 |         MASTER-SAAO | (19h 44m 10.05s , -10d 29m 55.4s) |   C |    60 | 17.5 |        
   11424 | 2025-10-05 17:37:13 |         MASTER-SAAO | (19h 42m 15.83s , -10d 14m 44.1s) |   C |    60 | 17.8 |        
Filter C is a clear (unfiltred) band. 


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