GCN Circular 45665

Subject
EP260920b: Global MASTER-Net observations report
Event
EP260920b
Date
2026-09-21T01:09:59Z (a day ago)
From
Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>
Via
D.Buckley (SAAO),

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 (Lomonosov MSU)

A. Gabovich, V.Yurkov (Blagoveschensk Educational StateUniversity)
A.Sosnovskij (Lomonosov MSU)

A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory)

L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez,
A.R.Corella, L.H.Rodriguez (INAOE, Guillermo Haro Astrophysics Observatory)

R.Rebolo (The Instituto de Astrofisica de Canarias)

O.Gress, N.Budnev(ISU)

M. Segura,  F. Podesta, R.Podesta, E. Gonzalez (Observatorio Astronomico Felix Aguilar (OAFA)


MASTER-SAAO robotic telescope  [1]  located in South Africa (South African Astronomical Observatory) was pointed to the EP260920b ( EP Team at NAOC/CAS <ep_ta@bao.ac.cn> et al., GCN 45664Loading...
 
 ) errorbox  755 sec after notice time and 38750 sec after trigger time at 2026-09-21 00:53:09 UT, with upper limit up to  18.0 mag. The observations began at zenith distance = 59 deg. The sun  altitude  is -43.7 deg. 

The galactic latitude b = -49 deg., longitude l = 21 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=3508203

We obtain a following upper limits.  

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

   38780 | 2026-09-21 00:53:09 |         MASTER-SAAO | (21h 39m 01.99s , -27d 59m 58.7s) |   C |    60 | 18.0 |        
   38874 | 2026-09-21 00:54:44 |         MASTER-SAAO | (21h 39m 05.58s , -27d 58m 18.4s) |   C |    60 | 18.0 |        
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