TITLE:   GCN CIRCULAR
NUMBER:  27645
SUBJECT: Swift GRB 200425A: Global MASTER-Net observations report 
DATE:    20/04/25 17:18:35 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

V. Lipunov, E. Gorbovskoy, V.Kornilov, N.Tyurina, P.Balanutsa, A.Kuznetsov, F.Balakin, 
V.Vladimirov, D. Vlasenko, I.Gorbunov, D.Zimnukhov, V.Senik, T.Pogrosheva,
D.Kuvshinov,  D. Cheryasov
(Lomonosov Moscow State University, SAI, Physics Department),

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

H.Levato 
(Instituto de Ciencias Astronomicas, de la Tierra y del Espacio ICATE),

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

D. Buckley 
(South African Astronomical Observatory),

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

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

V. Yurkov, A. Gabovich, Yu. Sergienko 
(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) was pointed to the Swift GRB 200425A ( M. G. Bernardini et al., GCN 27638) errorbox  60241 sec after notice time and 60296 sec after trigger time at 2020-04-25 17:01:17 UT, with upper limit up to  19.7 mag. Observations started at twilight.  The observations began at zenith distance = 45 deg. The sun  altitude  is -12.2 deg. 

The galactic latitude b = -21 deg., longitude l = 218 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=1343952

We obtain a following upper limits.  

Tmid-T0  |          Site       |Filt.| Expt. | Limit| Comment
_________|_____________________|_____|_______|______|________

   60386 |         MASTER-SAAO |   C |   180 | 19.2 |        
   60434 |         MASTER-SAAO |   C |   180 | 19.2 |        
   60666 |         MASTER-SAAO |   C |   180 | 19.7 |        
   60713 |         MASTER-SAAO |   C |   180 | 19.7 |        
Filter C is a clear (unfiltred) band. 


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