TITLE:   GCN CIRCULAR
NUMBER:  25429
SUBJECT: Swift GRB190821.72 Global MASTER-Net observations report 
DATE:    19/08/21 17:55:19 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 
(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 GRB190821.72 (trigger No 921722, 16h 40m 18.48s , -34d  1m 19.20s, R=0.05) errorbox  8 sec after notice time and 41 sec after trigger time at 2019-08-21 17:10:44 UT, with upper limit up to  18.4 mag. Observations started at twilight.  The observations began at zenit distance =  3 deg. The sun  altitude  is -12.4 deg. 

The galactic latitude b = -60 deg., longitude l = 98 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=1111516

We obtain a following upper limits.  

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

      46 |         MASTER-SAAO |  P\ |    10 | 16.3 |        
      73 |         MASTER-SAAO |  P\ |    10 | 16.4 |        
      98 |         MASTER-SAAO |  P\ |    60 | 17.3 |  Coadd 
     104 |         MASTER-SAAO |  P\ |    20 | 16.9 |        
     145 |         MASTER-SAAO |  P\ |    30 | 17.0 |        
     195 |         MASTER-SAAO |  P\ |    40 | 17.3 |        
     250 |         MASTER-SAAO |  P\ |   150 | 17.9 |  Coadd 
     256 |         MASTER-SAAO |  P\ |    50 | 17.4 |        
     328 |         MASTER-SAAO |  P\ |    60 | 17.6 |        
     508 |         MASTER-SAAO |  P\ |   270 | 18.1 |  Coadd 
     941 |         MASTER-SAAO |  P\ |   490 | 18.4 |  Coadd 


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