GCN Circular 44429

Subject
Fermi GRB 260429A: Global MASTER-Net observations report
Event
GRB 260429A
Date
2026-04-30T06:31:44Z (2 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 260429A ( Fermi GBM team, GCN 44425Loading...
 
 ) errorbox  24026 sec after notice time and 24067 sec after trigger time at 2026-04-30 06:05:09 UT, with upper limit up to  17.9 mag. The observations began at zenith distance = 65 deg. The sun  altitude  is -63.1 deg. 

The galactic latitude b =  7 deg., longitude l = 50 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=3281490

We obtain a following upper limits.  

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

   24098 | 2026-04-30 06:05:09 |         MASTER-OAFA | (18h 56m 08.86s , +18d 11m 55.3s) |   C |    60 | 17.6 |        
   24177 | 2026-04-30 06:06:28 |         MASTER-OAFA | (18h 56m 09.20s , +18d 12m 58.1s) |   C |    60 | 17.6 |        
   24255 | 2026-04-30 06:07:47 |         MASTER-OAFA | (18h 56m 14.55s , +18d 12m 00.2s) |   C |    60 | 17.5 |        
   24363 | 2026-04-30 06:09:04 |         MASTER-OAFA | (18h 56m 09.34s , +18d 11m 03.2s) |   C |   120 | 17.7 |        
   24498 | 2026-04-30 06:11:20 |         MASTER-OAFA | (18h 56m 15.66s , +18d 11m 31.9s) |   C |   120 | 17.8 |        
   24636 | 2026-04-30 06:13:37 |         MASTER-OAFA | (18h 56m 11.82s , +18d 12m 47.8s) |   C |   120 | 17.9 |        
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