GCN Circular 45290
Subject
Fermi GRB 260805A: Global MASTER-Net observations report
Event
Date
2026-08-05T18:16:07Z (2 days ago)
From
Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>
Via
email
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 260805A ( Fermi GBM team, GCN 45286) errorbox 26848 sec after notice time and 26944 sec after trigger time at 2026-08-05 16:47:37 UT, with upper limit up to 18.3 mag. Observations started at twilight. The observations began at zenith distance = 73 deg. The sun altitude is -10.3 deg.
The galactic latitude b = 38 deg., longitude l = 61 deg.
Real time updated cover map and OT discovered available here:
https://master.sai.msu.ru/site/master2/observ.php?id=3458691
We obtain a following upper limits.
Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________
26974 | 2026-08-05 16:47:37 | MASTER-SAAO | (16h 46m 23.79s , +37d 05m 59.0s) | C | 60 | 16.2 |
27079 | 2026-08-05 16:49:21 | MASTER-SAAO | (16h 46m 20.13s , +37d 05m 05.7s) | C | 60 | 16.5 |
27177 | 2026-08-05 16:51:00 | MASTER-SAAO | (16h 53m 24.94s , +39d 00m 48.3s) | C | 60 | 16.7 |
27274 | 2026-08-05 16:52:37 | MASTER-SAAO | (16h 33m 55.61s , +39d 00m 11.2s) | C | 60 | 17.1 |
27371 | 2026-08-05 16:54:13 | MASTER-SAAO | (16h 40m 42.58s , +35d 13m 18.4s) | C | 60 | 17.3 |
27468 | 2026-08-05 16:55:51 | MASTER-SAAO | (16h 42m 02.63s , +40d 54m 37.3s) | C | 60 | 17.1 |
27565 | 2026-08-05 16:57:28 | MASTER-SAAO | (16h 59m 16.29s , +35d 12m 25.7s) | C | 60 | 17.4 |
27662 | 2026-08-05 16:59:05 | MASTER-SAAO | (16h 27m 13.66s , +37d 07m 26.1s) | C | 60 | 17.8 |
27763 | 2026-08-05 17:00:46 | MASTER-SAAO | (17h 02m 11.79s , +40d 53m 02.6s) | C | 60 | 17.5 |
27865 | 2026-08-05 17:02:28 | MASTER-SAAO | (16h 54m 27.27s , +33d 17m 55.3s) | C | 60 | 17.9 |
27965 | 2026-08-05 17:04:07 | MASTER-SAAO | (17h 05m 29.88s , +37d 04m 27.6s) | C | 60 | 17.8 |
28066 | 2026-08-05 17:05:49 | MASTER-SAAO | (16h 36m 16.59s , +33d 18m 58.1s) | C | 60 | 18.2 |
28172 | 2026-08-05 17:07:35 | MASTER-SAAO | (16h 21m 54.26s , +40d 56m 57.8s) | C | 60 | 18.2 |
28273 | 2026-08-05 17:09:16 | MASTER-SAAO | (16h 22m 01.69s , +35d 14m 54.4s) | C | 60 | 18.3 |
28369 | 2026-08-05 17:10:52 | MASTER-SAAO | (16h 22m 02.96s , +35d 12m 55.3s) | C | 60 | 18.3 |
28476 | 2026-08-05 17:12:39 | MASTER-SAAO | (16h 51m 41.89s , +42d 49m 29.3s) | C | 60 | 17.9 |
28576 | 2026-08-05 17:14:19 | MASTER-SAAO | (17h 13m 05.13s , +39d 00m 07.2s) | C | 60 | 18.3 |
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