GCN Circular 35856

V. Lipunov, V.Kornilov, E. Gorbovskoy, K. Zhirkov, N.Tyurina, P.Balanutsa, A.Kuznetsov, V.Senik,  D. Vlasenko,
G.Antipov, D.Zimnukhov, E.Minkina, A.Chasovnikov, V.Topolev, D.Kuvshinov, D. Cheryasov, Ya.Kechin, Yu.Tselik, A. Sosnovskij
(Lomonosov Moscow State University, SAI, Physics Department),

R. Podesta, C.Lopez, F. Podesta, C.Francile
(Observatorio Astronomico Felix Aguilar OAFA),

R. Rebolo, M. Serra
(The Instituto de Astrofisica de Canarias),

D. Buckley
(South African Astronomical Observatory),

O.A. Gress, N.M. Budnev, O.Ershova
(Irkutsk State University, API),

L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez,
A.R.Corella, L.H.Rodriguez
(INAOE, Guillermo Haro Astrophysics Observatory),

A. Tlatov, D. Dormidontov
(Kislovodsk Solar Station of the Pulkovo Observatory),

V. Yurkov, A. Gabovich
(Blagoveschensk Educational State University)

MASTER-Amur robotic telescope  (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L)  located in Russia (Blagoveshchensk State Pedagogical University) started inspect of the Fermi GRB240303.51 (trigger No 731161136,20h 17m 57.60s , +01d 15m 36.0s, R=1) errorbox  30147 sec after notice time and 30152 sec after trigger time at 2024-03-03 20:41:24 UT, with upper limit up to  16.8 mag. Observations started at twilight.  The observations began at zenith distance = 71 deg. The sun  altitude  is -14.8 deg. 

The galactic latitude b = -19 deg., longitude l = 45 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=2390346

We obtain a following upper limits.  

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

   30183 | 2024-03-03 20:41:24 |         MASTER-Amur | (20h 09m 48.93s , +03d 08m 11.9s) |   C |    60 | 16.8 |        
   31548 | 2024-03-03 21:04:09 |         MASTER-Amur | (20h 09m 53.25s , +03d 04m 51.8s) |   C |    60 | 15.9 |        
   31628 | 2024-03-03 21:05:29 |         MASTER-Amur | (20h 15m 40.66s , +01d 11m 24.7s) |   C |    60 | 15.9 |        
   31708 | 2024-03-03 21:06:49 |         MASTER-Amur | (20h 23m 43.32s , +01d 13m 22.7s) |   C |    60 | 15.6 |        
   31788 | 2024-03-03 21:08:08 |         MASTER-Amur | (20h 16m 59.99s , +03d 06m 55.7s) |   C |    60 | 15.7 |        
   31867 | 2024-03-03 21:09:28 |         MASTER-Amur | (20h 25m 06.13s , +03d 06m 20.7s) |   C |    60 | 15.4 |        
Filter C is a clear (unfiltred) band. 


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