GCN Circular 23484

V. Lipunov, E. Gorbovskoy, V.Kornilov, D.Kuvshinov, N.Tyurina, P.Balanutsa,
A.Kuznetsov, V.V.Chazov, D. Vlasenko
Lomonosov Moscow State University,
Sternberg Astronomical Institute, Moscow State University

A. Tlatov, V.Senik, A.V. Parhomenko, D. Dormidontov
Kislovodsk Solar Station of the Pulkovo Observatory

K. Ivanov, O. Gres, N.M. Budnev, S. Yazev, O. Chuvalaev, V. Poleshchuk
Irkutsk State University

V. Yurkov, A. Gabovich, Yu. Sergienko
Blagoveschensk Educational State University, Blagoveschensk

R. Podesta, Carlos Lopez and F. Podesta
Observatorio Astronomico Felix Aguilar (OAFA)

Hugo Levato and Carlos Saffe
Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE)

R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres
The Instituto de Astrofisica de Canarias

D. Buckley, S. Potter, A. Kniazev, M. Kotze
South African Astronomical Observatory


MASTER-OAFA robotic telescope (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) was pointed 
to the INTEGRAL  GRB181201A ((Mereghetti et
al., GCN #23469) 10 sec after notice time and 18 sec 
after trigger time at 2018-12-01 02:40:30 UT. We discovered prompt  growing (one mag per 
minute) optical flash MASTER OT J211711.20-123751.4
(Podesta et al., GCN #23470; Gorbovskoy et al., Atel #12255) at RA,Dec  = 
21h 17m 11.20s -12d 37m 51.4s


Later we observed afterglow at MASTER-Kislovodsk (Lipunov et al., #23476), 
MASTER-SAAO, MASTER-IAC and MASTER-OAFA against in B,V,R,I and Clear fiters.
Observations are continuated.

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