GCN Circular 43654

Subject
Fermi GRB 260208D: Global MASTER-Net observations report
Event
GRB 260208D
Date
2026-02-09T00:30:26Z (6 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-OAFA robotic telescope  [1]  located in Argentina (OAFA observatory of San Juan National University) started inspect of the Fermi GRB 260208D ( Fermi GBM team, GCN 43653Loading...
 
 ) errorbox  9638 sec after notice time and 9659 sec after trigger time at 2026-02-09 00:23:45 UT, with upper limit up to  13.1 mag. Observations started at twilight.  The observations began at zenith distance = 83 deg. The sun  altitude  is -11.6 deg. 

The galactic latitude b = -51 deg., longitude l =  4 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=3126729

We obtain a following upper limits.  

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

    9675 | 2026-02-09 00:23:45 |         MASTER-OAFA | (21h 51m 37.44s , -38d 54m 31.8s) |   C |    30 | 12.8 |        
    9722 | 2026-02-09 00:24:32 |         MASTER-OAFA | (21h 51m 33.51s , -38d 53m 25.2s) |   C |    30 | 13.1 |        
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