GCN Circular 36173

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-SAAO robotic telescope  (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L)  located in South Africa (South African Astronomical Observatory) started inspect of the Fermi GRB240417.97 (trigger No 735089036,02h 10m 19.92s , -03d 31m 58.8s, R=21.22) errorbox  63251 sec after notice time and 63285 sec after trigger time at 2024-04-18 16:58:36 UT, with upper limit up to  17.0 mag. Observations started at twilight.  The observations began at zenith distance = 71 deg. The sun  altitude  is -10.2 deg. 

The galactic latitude b = -59 deg., longitude l = 166 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=2425848

We obtain a following upper limits.  

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

   63316 | 2024-04-18 16:58:36 |         MASTER-SAAO | (03h 17m 20.19s , -08d 12m 54.6s) |   C |    60 | 14.3 |        
   63395 | 2024-04-18 16:59:56 |         MASTER-SAAO | (03h 31m 11.88s , -04d 25m 53.4s) |   C |    60 | 14.7 |        
   63850 | 2024-04-18 17:07:31 |         MASTER-SAAO | (03h 18m 29.94s , -10d 08m 18.3s) |   C |    60 | 16.2 |        
   63850 | 2024-04-18 17:07:31 |         MASTER-SAAO | (03h 20m 16.37s , -10d 20m 55.8s) |   C |    60 | 16.9 |        
   63930 | 2024-04-18 17:08:50 |         MASTER-SAAO | (03h 04m 26.97s , -12d 00m 30.8s) |   C |    60 | 14.2 |        
   63930 | 2024-04-18 17:08:50 |         MASTER-SAAO | (03h 06m 13.89s , -12d 13m 09.8s) |   C |    60 | 16.6 |        
   64009 | 2024-04-18 17:10:10 |         MASTER-SAAO | (03h 31m 48.88s , -06d 19m 29.0s) |   C |    60 | 16.1 |        
   64009 | 2024-04-18 17:10:10 |         MASTER-SAAO | (03h 33m 34.13s , -06d 32m 06.3s) |   C |    60 | 17.0 |        
   64737 | 2024-04-18 17:22:18 |         MASTER-SAAO | (03h 19m 29.66s , -08d 26m 39.1s) |   C |    60 | 17.0 |        
   64817 | 2024-04-18 17:23:38 |         MASTER-SAAO | (03h 33m 15.06s , -04d 36m 56.4s) |   C |    60 | 17.0 |        
   65502 | 2024-04-18 17:35:03 |         MASTER-SAAO | (03h 20m 39.07s , -10d 20m 17.5s) |   C |    60 | 17.0 |        
Filter C is a clear (unfiltred) band. 


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