TITLE:   GCN CIRCULAR
NUMBER:  30575
SUBJECT: Fermi  trigger No 649519043: Global MASTER-Net observations report 
DATE:    21/08/01 17:15:36 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-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) started inspect of the Fermi GRB210801.58 (trigger No 649519043,16h 51m 04.80s , -45d 49m 12.0s, R=1.59) errorbox  9997 sec after notice time and 10005 sec after trigger time at 2021-08-01 16:44:04 UT, with upper limit up to  18.6 mag. Observations started at twilight.  The observations began at zenith distance = 27 deg. The sun  altitude  is -9.2 deg. 

The galactic latitude b = -1 deg., longitude l = 340 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=1677776

We obtain a following upper limits.  

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

   10036 | 2021-08-01 16:44:04 |         MASTER-SAAO | (16h 45m 32.58s , -46d 23m 06.5s) |   C |    60 | 16.5 |        
   10115 | 2021-08-01 16:45:24 |         MASTER-SAAO | (16h 57m 02.64s , -46d 24m 34.4s) |   C |    60 | 17.2 |        
   10195 | 2021-08-01 16:46:43 |         MASTER-SAAO | (16h 54m 49.52s , -44d 28m 37.9s) |   C |    60 | 17.4 |        
   10275 | 2021-08-01 16:48:03 |         MASTER-SAAO | (17h 06m 02.19s , -44d 30m 32.8s) |   C |    60 | 17.4 |        
   10355 | 2021-08-01 16:49:23 |         MASTER-SAAO | (16h 33m 29.31s , -44d 28m 35.8s) |   C |    60 | 17.5 |        
   10435 | 2021-08-01 16:50:43 |         MASTER-SAAO | (16h 44m 41.94s , -44d 28m 02.3s) |   C |    60 | 17.6 |        
   10714 | 2021-08-01 16:55:22 |         MASTER-SAAO | (16h 36m 42.07s , -48d 17m 25.5s) |   C |    60 | 17.4 |        
   10794 | 2021-08-01 16:56:42 |         MASTER-SAAO | (16h 48m 39.41s , -48d 16m 14.7s) |   C |    60 | 17.4 |        
   10877 | 2021-08-01 16:58:05 |         MASTER-SAAO | (16h 44m 03.48s , -42d 34m 25.2s) |   C |    60 | 17.9 |        
   10957 | 2021-08-01 16:59:25 |         MASTER-SAAO | (16h 54m 48.86s , -42d 35m 21.9s) |   C |    60 | 18.6 |        
   11036 | 2021-08-01 17:00:44 |         MASTER-SAAO | (16h 45m 25.45s , -46d 21m 51.8s) |   C |    60 | 17.8 |        
   11127 | 2021-08-01 17:02:15 |         MASTER-SAAO | (16h 57m 06.68s , -46d 23m 20.8s) |   C |    60 | 18.5 |        
   11206 | 2021-08-01 17:03:34 |         MASTER-SAAO | (16h 54m 44.85s , -44d 30m 16.7s) |   C |    60 | 18.4 |        
Filter C is a clear (unfiltred) band. 


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