GCN Circular 31607

V. Lipunov, V.Kornilov, E.Gorbovskoy, K.Zhirkov, N.Tyurina, P.Balanutsa, A.Kuznetsov, 
D. Vlasenko, G.Antipov, D.Zimnukhov, V.Senik, T.Pogrosheva, E.Minkina,
A.Chasovnikov, V.Topolev, V.Grinshpun, 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
(Irkutsk State University, API),

B.L.Carrasco, J.R.Valdes,V.Chavushyan, C.J.Martinez, V.M.Patino Alvarez,
M.L.H.Rodriguez (INAOE, OAGH)

A. Tlatov, D. Dormidontov 
(Kislovodsk Solar Station of the Pulkovo Observatory),

A. Gabovich, V.Yurkov 
(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) was pointed to the Swift GRB220218.94 (trigger No 1093860,08h 55m 19.20s , +31d 59m 02.4s, R=0.05) errorbox  8 sec after notice time and 93 sec after trigger time at 2022-02-18 22:30:33 UT, with upper limit up to  16.8 mag. The observations began at zenith distance = 65 deg. The sun  altitude  is -46.2 deg. 

MASTER-Kislovodsk robotic telescope  located in Russia (Lomonosov MSU, Kislovodsk Solar Station of Pulkovo observatory) was pointed to the Swift GRB220218.94 errorbox  32 sec after notice time and 117 sec after trigger time at 2022-02-18 22:30:56 UT, with upper limit up to  15.9 mag. The observations began at zenith distance = 29 deg. The sun  altitude  is -55.4 deg. 

The galactic latitude b = 40 deg., longitude l = 193 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=1887825

We obtain a following upper limits.  

Tmid-T0  |          Site       |Filt.| Expt. | Limit| Comment
_________|_____________________|_____|_______|______|________

     104 |         MASTER-SAAO | P\  |    20 | 16.5 |        
     127 |   MASTER-Kislovodsk |  P- |    20 | 15.1 |        
     141 |         MASTER-SAAO | P\  |    30 | 16.8 |        
     172 |   MASTER-Kislovodsk |  P- |    30 | 15.1 |        
     182 |         MASTER-SAAO | P\  |    30 | 16.8 |        
     227 |   MASTER-Kislovodsk |  P- |    40 | 15.9 |        
     230 |         MASTER-SAAO | P\  |    40 | 16.8 |        


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