TITLE:   GCN CIRCULAR
NUMBER:  20541
SUBJECT: GRB 170127B: MASTER-Kislovodsk early optical observations
DATE:    17/01/27 16:05:37 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

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

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

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

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

R. Podesta, Claudio Mallamaci, Carlos Lopez and Federico Podesta
Observatorio Astronomico Felix Aguilar (OAFA)

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

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

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


MASTER II  robotic telescope (MASTER-Net: http://observ.pereplet.ru) 
located in Kislovodsk was pointed to the  GRB170127B 37 sec after notice 
time and 52 sec after trigger time at 2017-01-27 15:14:21 UT in two 
polarization. On our first 
(10s exposure)  set we haven`t found optical transient  within SWIFT 
error-box (Cannizzo et al GCN 20540).
The 5-sigma upper limit has been about 17.0 mag on single (10 s) and 19.5 
on  coadd (total exposure 540 s) images.
The message may be cited.

====================================================================

The observations made on zenit distance = 76 degrees, galaxy latitude b =  -83 degree.
The moon ( 0 % bright part) below the horizon (The altitude of the Moon is 
-14 degree ).
Observations started at twilight.
The sun  altitude  is -11.4 degree.