GCN Circular 36645

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 GRB240608.10 (trigger No 739506569,21h 55m 00.00s , +20d 25m 48.0s, R=2.81) errorbox  1583 sec after notice time and 1616 sec after trigger time at 2024-06-08 02:56:20 UT, with upper limit up to  19.2 mag. The observations began at zenith distance = 54 deg. The sun  altitude  is -32.7 deg. 

The galactic latitude b = -26 deg., longitude l = 77 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=2485687

We obtain a following upper limits.  

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

    1646 | 2024-06-08 02:56:20 |         MASTER-SAAO | (21h 39m 31.37s , +21d 46m 29.7s) |   C |    60 | 18.5 |        
    1805 | 2024-06-08 02:58:59 |         MASTER-SAAO | (21h 39m 13.96s , +19d 50m 39.1s) |   C |    60 | 18.6 |        
    1966 | 2024-06-08 03:01:39 |         MASTER-SAAO | (21h 41m 32.98s , +23d 40m 11.2s) |   C |    60 | 18.9 |        
    2204 | 2024-06-08 03:05:37 |         MASTER-SAAO | (21h 46m 53.53s , +19d 50m 45.6s) |   C |    60 | 18.6 |        
    2283 | 2024-06-08 03:06:57 |         MASTER-SAAO | (21h 55m 18.79s , +19d 51m 35.8s) |   C |    60 | 19.2 |        
Filter C is a clear (unfiltred) band. 


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