GCN Circular 43782

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) was pointed to the IceCube Alert 260217A (trigger No 80851825,05h 03m 33.60s , +14d 37m 48.0s, R=0.68) errorbox  16 sec after notice time and 1 days 73773 sec after trigger time at 2026-02-19 02:24:58 UT, with upper limit up to  20.1 mag. The observations began at zenith distance = 60 deg. The sun  altitude  is -35.3 deg. 

The galactic latitude b = -15 deg., longitude l = 187 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=3144643

We obtain a following upper limits.  

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

  160204 | 2026-02-19 02:24:58 |         MASTER-OAFA | (05h 03m 45.23s , +14d 51m 29.0s) |   C |    60 | 19.8 |        
  160264 | 2026-02-19 02:24:58 |         MASTER-OAFA | (05h 03m 45.23s , +14d 51m 29.0s) |   C |   180 | 20.1 |  Coadd 
  160264 | 2026-02-19 02:24:58 |             MASTER- | (05h 04m 46.08s , +13d 52m 00.1s) |   C |   180 | 18.5 |        
  160264 | 2026-02-19 02:24:58 |             MASTER- | (05h 03m 26.64s , +14d 25m 36.7s) |   C |   180 | 17.8 |        
  160269 | 2026-02-19 02:26:03 |         MASTER-OAFA | (05h 03m 45.21s , +14d 51m 29.3s) |   C |    60 | 19.8 |        
  160335 | 2026-02-19 02:27:09 |         MASTER-OAFA | (05h 03m 45.18s , +14d 51m 29.4s) |   C |    60 | 19.8 |        
  160453 | 2026-02-19 02:28:07 |             MASTER- | (05h 04m 43.62s , +13d 53m 35.3s) |   C |   180 | 18.6 |        
  160453 | 2026-02-19 02:28:07 |             MASTER- | (05h 03m 24.11s , +14d 27m 11.9s) |   C |   180 | 17.9 |        
  160461 | 2026-02-19 02:28:15 |         MASTER-OAFA | (05h 03m 45.15s , +14d 51m 29.9s) |   C |   180 | 20.1 |  Coadd 
  160641 | 2026-02-19 02:31:15 |             MASTER- | (05h 04m 43.75s , +13d 51m 54.5s) |   C |   180 | 18.5 |        
  160641 | 2026-02-19 02:31:15 |             MASTER- | (05h 03m 24.24s , +14d 25m 30.5s) |   C |   180 | 18.1 |        
  160830 | 2026-02-19 02:34:24 |             MASTER- | (05h 04m 46.70s , +13d 53m 29.4s) |   C |   180 | 18.4 |        
  160830 | 2026-02-19 02:34:24 |             MASTER- | (05h 03m 27.15s , +14d 27m 05.6s) |   C |   180 | 17.9 |        
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