[vsnet-grb-info 27957] Fermi GRB 210520A: Global MASTER-Net observations report

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  30060
SUBJECT: Fermi GRB 210520A: Global MASTER-Net observations report 
DATE:    21/05/20 22:50:11 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov at 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),

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-OAFA robotic telescope  (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L)  located in Argentina (OAFA observatory of San Juan National University) started inspect of the Fermi GRB 210520A ( Fermi GBM team, GCN 30059) errorbox  12138 sec after notice time and 12187 sec after trigger time at 2021-05-20 22:30:10 UT, with upper limit up to  17.0 mag. Observations started at twilight.  The observations began at zenith distance = 39 deg. The sun  altitude  is -10.0 deg. 

The galactic latitude b = -14 deg., longitude l = 285 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=1617942

We obtain a following upper limits.  

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

   12218 | 2021-05-20 22:30:10 |         MASTER-OAFA | (09h 02m 19.62s , -69d 42m 16.2s) |   C |    60 | 16.8 |        
   12297 | 2021-05-20 22:31:29 |         MASTER-OAFA | (09h 24m 33.57s , -69d 42m 48.7s) |   C |    60 | 17.0 |        
   12376 | 2021-05-20 22:32:49 |         MASTER-OAFA | (08h 58m 19.03s , -67d 47m 42.0s) |   C |    60 | 17.0 |        
Filter C is a clear (unfiltred) band. 


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