[vsnet-grb-info 28573] Fermi GRB 210821A: Global MASTER-Net observations report

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  30676
SUBJECT: Fermi GRB 210821A: Global MASTER-Net observations report 
DATE:    21/08/21 23:19:57 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-Kislovodsk robotic telescope  (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L)  located in Russia (Lomonosov MSU, Kislovodsk Solar Station of Pulkovo observatory) started inspect of the Fermi GRB 210821A ( Fermi GBM team, GCN 30671) errorbox  50201 sec after notice time and 50230 sec after trigger time at 2021-08-21 21:37:39 UT, with upper limit up to  12.6 mag. The observations began at zenith distance = 80 deg. The sun  altitude  is -34.8 deg. 

MASTER-Tavrida robotic telescope  located in Russia (Lomonosov MSU, SAI Crimea astronomical station) started inspect of the Fermi GRB 210821A errorbox  54267 sec after notice time and 54295 sec after trigger time at 2021-08-21 22:45:24 UT, with upper limit up to  16.8 mag. The observations began at zenith distance = 76 deg. The sun  altitude  is -32.5 deg. 

The galactic latitude b = -49 deg., longitude l = 190 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=1696282

We obtain a following upper limits.  

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

   50261 | 2021-08-21 21:37:39 |   MASTER-Kislovodsk | (03h 06m 09.35s , -06d 43m 00.6s) |   C |    60 | 12.0 |        
   50421 | 2021-08-21 21:40:19 |   MASTER-Kislovodsk | (03h 05m 37.89s , -04d 47m 03.2s) |   C |    60 | 12.6 |        
   50742 | 2021-08-21 21:45:40 |   MASTER-Kislovodsk | (03h 06m 55.76s , -08d 34m 58.7s) |   C |    60 | 12.6 |        
   54326 | 2021-08-21 22:45:24 |      MASTER-Tavrida | (03h 20m 05.86s , -06d 10m 34.8s) |   C |    60 | 16.2 |        
   54815 | 2021-08-21 22:53:33 |      MASTER-Tavrida | (03h 12m 55.02s , -08d 06m 16.1s) |   C |    60 | 16.3 |        
   55229 | 2021-08-21 23:00:27 |      MASTER-Tavrida | (03h 21m 00.76s , -08d 04m 15.3s) |   C |    60 | 16.3 |        
   55410 | 2021-08-21 23:03:28 |      MASTER-Tavrida | (03h 12m 06.09s , -06d 12m 19.0s) |   C |    60 | 16.8 |        
   55661 | 2021-08-21 23:07:39 |      MASTER-Tavrida | (03h 20m 05.24s , -06d 10m 15.9s) |   C |    60 | 16.6 |        
   56075 | 2021-08-21 23:14:33 |      MASTER-Tavrida | (03h 12m 54.77s , -08d 04m 12.7s) |   C |    60 | 16.8 |        
   56154 | 2021-08-21 23:15:52 |      MASTER-Tavrida | (03h 21m 06.28s , -08d 05m 06.5s) |   C |    60 | 16.5 |        
Filter C is a clear (unfiltred) band. 


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