TITLE:   GCN CIRCULAR
NUMBER:  29352
SUBJECT: Fermi  trigger No 633257525: Global MASTER-Net observations report 
DATE:    21/01/26 01:45:28 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-Tavrida robotic telescope  (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L)  located in Russia (Lomonosov MSU, SAI Crimea astronomical station) started inspect of the Fermi GRB210125.37 (trigger No 633257525,05h 24m 14.40s , +51d 13m 48.0s, R=6.51) errorbox  49550 sec after notice time and 49608 sec after trigger time at 2021-01-25 22:38:49 UT, with upper limit up to  17.6 mag. The observations began at zenith distance = 40 deg. The sun  altitude  is -63.2 deg. 

The galactic latitude b =  9 deg., longitude l = 159 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=1532868

We obtain a following upper limits.  

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

   49639 | 2021-01-25 22:38:49 |      MASTER-Tavrida | (05h 09m 30.77s , +57d 48m 17.0s) |   C |    60 | 15.9 |        
   49639 | 2021-01-25 22:38:49 |      MASTER-Tavrida | (04h 58m 10.05s , +57d 50m 31.8s) |   C |    60 | 15.9 |        
   50539 | 2021-01-25 22:53:49 |      MASTER-Tavrida | (05h 09m 33.82s , +57d 47m 22.2s) |   C |    60 | 16.6 |        
   50539 | 2021-01-25 22:53:49 |      MASTER-Tavrida | (04h 58m 11.92s , +57d 49m 42.2s) |   C |    60 | 16.9 |        
   53002 | 2021-01-25 23:34:52 |      MASTER-Tavrida | (05h 09m 44.57s , +57d 45m 28.8s) |   C |    60 | 17.4 |        
   53002 | 2021-01-25 23:34:52 |      MASTER-Tavrida | (04h 58m 21.67s , +57d 48m 15.7s) |   C |    60 | 17.6 |        
   57686 | 2021-01-26 00:52:56 |      MASTER-Tavrida | (04h 53m 43.13s , +55d 40m 58.2s) |   C |    60 | 17.0 |        
   57686 | 2021-01-26 00:52:56 |      MASTER-Tavrida | (04h 43m 00.78s , +55d 44m 16.7s) |   C |    60 | 17.1 |        
   58758 | 2021-01-26 01:10:48 |      MASTER-Tavrida | (04h 53m 47.62s , +55d 39m 24.9s) |   C |    60 | 16.9 |        
   58758 | 2021-01-26 01:10:48 |      MASTER-Tavrida | (04h 43m 07.31s , +55d 42m 34.6s) |   C |    60 | 16.8 |        
Filter C is a clear (unfiltred) band. 


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