GCN Circular 44511

Subject
Fermi GRB 260510A: Global MASTER-Net observations report
Event
GRB 260510A
Date
2026-05-10T06:30:25Z (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-OAFA robotic telescope  [1]  located in Argentina (OAFA observatory of San Juan National University) started inspect of the Fermi GRB 260510A ( Fermi GBM team, GCN 44508Loading...
 
 ) errorbox  12795 sec after notice time and 12848 sec after trigger time at 2026-05-10 06:20:28 UT, with upper limit up to  17.6 mag. The observations began at zenith distance = 80 deg. The sun  altitude  is -61.8 deg. 

The galactic latitude b = -73 deg., longitude l = 333 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=3304437

We obtain a following upper limits.  

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

   12879 | 2026-05-10 06:20:28 |         MASTER-OAFA | (00h 01m 07.12s , -42d 06m 59.6s) |   C |    60 | 17.0 |        
   12956 | 2026-05-10 06:21:45 |         MASTER-OAFA | (00h 01m 04.44s , -42d 05m 38.2s) |   C |    60 | 16.9 |        
   13034 | 2026-05-10 06:23:03 |         MASTER-OAFA | (00h 01m 02.62s , -44d 07m 12.4s) |   C |    60 | 17.4 |        
   13109 | 2026-05-10 06:24:18 |         MASTER-OAFA | (00h 01m 04.74s , -44d 05m 38.9s) |   C |    60 | 17.5 |        
   13186 | 2026-05-10 06:25:35 |         MASTER-OAFA | (00h 00m 59.38s , -44d 06m 16.7s) |   C |    60 | 17.6 |        
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