GCN Circular 45656

Subject
EP260917a: Global MASTER-Net observations report
Event
EP260917a
Date
2026-09-20T10:09:33Z (2 days ago)
From
Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>
Via
M. Segura,  F. Podesta, R.Podesta, E. Gonzalez (Observatorio Astronomico Felix Aguilar (OAFA)

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)

D.Buckley (SAAO),

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)


MASTER-Tavrida robotic telescope  [1]  located in Russia (Lomonosov MSU, SAI Crimea astronomical station) was pointed to the EP260917a ( EP Team at NAOC/CAS <ep_ta@bao.ac.cn> et al., GCN 45621Loading...
 
 ) errorbox  5669 sec after notice time and 1 days 24067 sec after trigger time at 2026-09-19 17:19:38 UT, with upper limit up to  17.3 mag. Observations started at twilight.  The observations began at zenith distance = 50 deg. The sun  altitude  is -17.0 deg. 

MASTER-OAFA robotic telescope  located in Argentina (OAFA observatory of San Juan National University) was pointed to the EP260917a errorbox  35682 sec after notice time and 1 days 54080 sec after trigger time at 2026-09-20 01:39:51 UT, with upper limit up to  18.2 mag. The observations began at zenith distance = 46 deg. The sun  altitude  is -39.7 deg. 

The galactic latitude b = -39 deg., longitude l = 73 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=3507281

We obtain a following upper limits.  

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

  110498 | 2026-09-19 17:19:38 |      MASTER-Tavrida | (22h 17m 15.77s , +10d 02m 03.4s) |   C |    60 | 17.2 |        
  110498 | 2026-09-19 17:19:38 |      MASTER-Tavrida | (22h 17m 15.04s , +10d 01m 19.4s) |   C |    60 | 17.3 |        
  140511 | 2026-09-20 01:39:51 |         MASTER-OAFA | (22h 19m 36.59s , +09d 24m 16.7s) |   C |    60 | 17.1 |        
  140571 | 2026-09-20 01:39:51 |         MASTER-OAFA | (22h 19m 36.59s , +09d 24m 16.7s) |   C |   180 | 18.0 |  Coadd 
  140587 | 2026-09-20 01:41:07 |         MASTER-OAFA | (22h 19m 43.55s , +09d 23m 15.0s) |   C |    60 | 17.6 |        
  140663 | 2026-09-20 01:42:24 |         MASTER-OAFA | (22h 19m 35.65s , +09d 22m 13.0s) |   C |    60 | 17.7 |        
  140742 | 2026-09-20 01:43:42 |         MASTER-OAFA | (22h 19m 41.48s , +09d 22m 36.9s) |   C |    60 | 17.8 |        
  140802 | 2026-09-20 01:43:42 |         MASTER-OAFA | (22h 19m 41.47s , +09d 22m 36.9s) |   C |   180 | 18.0 |  Coadd 
  140816 | 2026-09-20 01:44:57 |         MASTER-OAFA | (22h 19m 38.97s , +09d 23m 59.5s) |   C |    60 | 17.7 |        
  140892 | 2026-09-20 01:46:12 |         MASTER-OAFA | (22h 19m 38.70s , +09d 22m 06.0s) |   C |    60 | 17.0 |        
  143523 | 2026-09-20 02:30:03 |         MASTER-OAFA | (22h 19m 26.85s , +09d 21m 04.0s) |   C |    60 | 17.6 |        
  143583 | 2026-09-20 02:30:03 |         MASTER-OAFA | (22h 19m 26.85s , +09d 21m 04.0s) |   C |   180 | 18.2 |  Coadd 
  143600 | 2026-09-20 02:31:20 |         MASTER-OAFA | (22h 19m 19.87s , +09d 20m 22.2s) |   C |    60 | 18.1 |        
  143677 | 2026-09-20 02:32:37 |         MASTER-OAFA | (22h 19m 20.46s , +09d 21m 16.6s) |   C |    60 | 17.8 |        
  143753 | 2026-09-20 02:33:53 |         MASTER-OAFA | (22h 19m 25.80s , +09d 20m 11.7s) |   C |    60 | 18.0 |        
  143813 | 2026-09-20 02:33:53 |         MASTER-OAFA | (22h 19m 25.80s , +09d 20m 11.7s) |   C |   180 | 18.2 |  Coadd 
  143829 | 2026-09-20 02:35:09 |         MASTER-OAFA | (22h 19m 20.27s , +09d 19m 05.9s) |   C |    60 | 17.8 |        
  143906 | 2026-09-20 02:36:27 |         MASTER-OAFA | (22h 19m 25.24s , +09d 19m 13.2s) |   C |    60 | 17.5 |        
  143984 | 2026-09-20 02:37:44 |         MASTER-OAFA | (22h 19m 21.46s , +09d 20m 46.7s) |   C |    60 | 17.9 |        
  144044 | 2026-09-20 02:37:44 |         MASTER-OAFA | (22h 19m 21.46s , +09d 20m 46.7s) |   C |   180 | 18.0 |  Coadd 
  144058 | 2026-09-20 02:38:58 |         MASTER-OAFA | (22h 19m 21.04s , +09d 19m 10.4s) |   C |    60 | 16.9 |        
  144133 | 2026-09-20 02:40:13 |         MASTER-OAFA | (22h 19m 24.13s , +09d 20m 35.2s) |   C |    60 | 17.6 |        
  144210 | 2026-09-20 02:41:30 |         MASTER-OAFA | (22h 19m 17.16s , +09d 19m 35.9s) |   C |    60 | 17.5 |        
  144270 | 2026-09-20 02:41:30 |         MASTER-OAFA | (22h 19m 17.15s , +09d 19m 35.9s) |   C |   180 | 17.5 |  Coadd 
  144287 | 2026-09-20 02:42:48 |         MASTER-OAFA | (22h 19m 16.67s , +09d 20m 29.3s) |   C |    60 | 17.2 |        
  144362 | 2026-09-20 02:44:02 |         MASTER-OAFA | (22h 19m 22.45s , +09d 19m 24.6s) |   C |    60 | 15.8 |        
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