TITLE:   GCN CIRCULAR
NUMBER:  29587
SUBJECT: Fermi  trigger No 636168178: Global MASTER-Net observations report 
DATE:    21/02/28 10:15:08 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),

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 GRB210228.06 (trigger No 636168178,18h 53m 55.20s , -43d 07m 48.0s, R=2.29) errorbox  15502 sec after notice time and 29006 sec after trigger time at 2021-02-28 09:26:20 UT, with upper limit up to  17.1 mag. Observations started at twilight.  The observations began at zenith distance = 43 deg. The sun  altitude  is -12.9 deg. 

The galactic latitude b = -19 deg., longitude l = 354 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=1557639

We obtain a following upper limits.  

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

   29036 | 2021-02-28 09:26:20 |         MASTER-OAFA | (18h 54m 03.49s , -42d 41m 37.2s) |   C |    60 | 16.2 |        
   29116 | 2021-02-28 09:27:39 |         MASTER-OAFA | (19h 04m 56.17s , -42d 42m 56.1s) |   C |    60 | 17.1 |        
   29401 | 2021-02-28 09:32:25 |         MASTER-OAFA | (19h 09m 26.91s , -44d 42m 22.8s) |   C |    60 | 17.1 |        
   29691 | 2021-02-28 09:37:15 |         MASTER-OAFA | (19h 04m 11.51s , -46d 43m 00.3s) |   C |    60 | 16.9 |        
   29977 | 2021-02-28 09:42:01 |         MASTER-OAFA | (18h 54m 11.27s , -42d 42m 38.0s) |   C |    60 | 16.5 |        
   30056 | 2021-02-28 09:43:20 |         MASTER-OAFA | (19h 04m 52.39s , -42d 43m 56.5s) |   C |    60 | 16.3 |        
   30136 | 2021-02-28 09:44:40 |         MASTER-OAFA | (19h 01m 59.69s , -40d 41m 58.5s) |   C |    60 | 16.2 |        
Filter C is a clear (unfiltred) band. 


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