GCN Circular 26596

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

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

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

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

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

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

Hugo Levato
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

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) was pointed to the  GRB191227.07 31 sec after notice 
time and 51 sec after trigger time at 2019-12-27 01:40:28 UT. On our first 
(10s exposure)  set we  found 1 optical transient within Swift error-box 
(ra=319.167 dec=-16.7033 r=0.05) brighter than  15.3.


  T-Tmid      Date      Time       Expt.        Ra                Dec           Mag
---------|---------------------|-------|-----------------|-----------------|-------
       56   2019-12-27 01:40:28      10   (21h 16m 37.28s , -16d 43m 33.5s)     14.4

The 5-sigma upper limit has been about  15.3mag
The message may be cited.



The OT has irregular early time  behaviour since 51.1 till 501.5 seconds 
after the trigger.


The galactic latitude b = -40 deg., longitude l = 34 deg.
The observations made on zenith distance = 83 deg.The moon ( 1 % bright 
part) below the horizon (The altitude of the Moon is -14 deg. ).
The sun  altitude  is -20.6 deg.