TITLE:   GCN CIRCULAR
NUMBER:  40617
SUBJECT: Fermi  trigger No 770638414: Global MASTER-Net observations report
DATE:    25/06/03 11:32:32 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>

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  (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L)  located in Argentina (OAFA observatory of San Juan National University) started inspect of the Fermi GRB250603.43 (trigger No 770638414,19h 14m 55.20s , +26d 21m 36.0s, R=7.82) errorbox  165 sec after notice time and 195 sec after trigger time at 2025-06-03 10:16:44 UT, with upper limit up to  16.8 mag. Observations started at twilight.  The observations began at zenith distance = 73 deg. The sun  altitude  is -14.5 deg. 

The galactic latitude b =  7 deg., longitude l = 59 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=2890867

We obtain a following upper limits.  

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

     215 | 2025-06-03 10:16:44 |         MASTER-OAFA | (19h 39m 27.79s , +30d 15m 05.9s) |   C |    40 | 16.8 |        
     266 | 2025-06-03 10:17:31 |         MASTER-OAFA | (19h 39m 27.74s , +30d 15m 07.5s) |   C |    50 | 16.8 |        
     327 | 2025-06-03 10:18:27 |         MASTER-OAFA | (19h 39m 27.67s , +30d 15m 08.4s) |   C |    60 | 16.8 |        
     399 | 2025-06-03 10:19:33 |         MASTER-OAFA | (19h 39m 27.58s , +30d 15m 09.3s) |   C |    70 | 16.8 |        
Filter C is a clear (unfiltred) band. 


The observation and reduction will continue. 
The message may be cited.