GCN 45185: Fermi GRB 260718A: Global MASTER-Net observations report

2026-07-18T20:46:39.605Z | rev 0 | event: GRB 260718A
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),
M. Segura,  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-SAAO robotic telescope  [1]  located in South Africa (South African Astronomical Observatory) started inspect of the Fermi GRB 260718A ( A. Holzmann Airasca et al., GCN 45181) errorbox  30093 sec after notice time and 30129 sec after trigger time at 2026-07-18 19:38:45 UT, with upper limit up to  16.1 mag. The observations began at zenith distance = 79 deg. The sun  altitude  is -47.9 deg. 

The galactic latitude b = -70 deg., longitude l = 272 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=3433050

We obtain a following upper limits.  

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

   30160 | 2026-07-18 19:38:45 |         MASTER-SAAO | (00h 43m 50.40s , -54d 15m 03.4s) |   C |    60 | 15.0 |        
   30564 | 2026-07-18 19:45:29 |         MASTER-SAAO | (01h 17m 13.48s , -58d 01m 45.8s) |   C |    60 | 16.1 |        
   30772 | 2026-07-18 19:48:57 |         MASTER-SAAO | (00h 41m 49.87s , -52d 21m 34.2s) |   C |    60 | 14.7 |        
   31386 | 2026-07-18 19:59:10 |         MASTER-SAAO | (00h 40m 00.33s , -50d 27m 42.3s) |   C |    60 | 15.5 |        
   31486 | 2026-07-18 20:00:50 |         MASTER-SAAO | (01h 13m 14.66s , -56d 07m 02.2s) |   C |    60 | 15.4 |        
   31895 | 2026-07-18 20:07:40 |         MASTER-SAAO | (01h 09m 43.51s , -54d 13m 28.2s) |   C |    60 | 13.7 |        
   32004 | 2026-07-18 20:09:28 |         MASTER-SAAO | (01h 09m 45.18s , -54d 14m 59.8s) |   C |    60 | 15.1 |        
   32521 | 2026-07-18 20:18:06 |         MASTER-SAAO | (01h 06m 29.78s , -52d 20m 35.2s) |   C |    60 | 12.7 |        
   32725 | 2026-07-18 20:21:29 |         MASTER-SAAO | (01h 03m 42.42s , -50d 26m 49.3s) |   C |    60 | 14.7 |        
   33229 | 2026-07-18 20:29:53 |         MASTER-SAAO | (01h 40m 19.62s , -56d 07m 30.7s) |   C |    60 | 13.7 |        
   33327 | 2026-07-18 20:31:31 |         MASTER-SAAO | (01h 35m 37.77s , -54d 14m 35.3s) |   C |    60 | 12.8 |        
   33429 | 2026-07-18 20:33:14 |         MASTER-SAAO | (01h 35m 33.23s , -54d 13m 49.2s) |   C |    60 | 14.4 |        
   33947 | 2026-07-18 20:41:51 |         MASTER-SAAO | (01h 31m 17.62s , -52d 21m 15.0s) |   C |    60 | 13.6 |        
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