TITLE:   GCN CIRCULAR
NUMBER:  18392
SUBJECT: Swift Trigger 657564: MASTER-NET early optical observations. 
DATE:    15/10/05 09:23:49 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

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

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

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

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

V.Yurkov, Yu.Sergienko, D.Varda, E.Sinyakov
Blagoveschensk Educational State University, Blagoveschensk


V.Krushinski, I.Zalozhnih,  A. Popov
Ural Federal University, Kourovka

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

Claudio Mallamaci, Carlos Lopez and Federico Podest
Observatorio Astronomico Felix Aguilar (OAFA)



MASTER II  robotic telescope (MASTER-Net: http://observ.pereplet.ru) 
located in SAAO was pointed to the probable GRB  (Swift Trigger 657564) 24 
sec after notice time and 108 sec after trigger time at 2015-10-04 
18:10:55 UT. On our first (20s exposure)  set we not  found  optical 
transient within SWIFT error-box (Cenko et. al GCN 18389) brighter then 
16.0.

Analysis of highly complicated proximity to the Milky Way (Galactic 
latitude l=-3.5) and strong winds (speed=65 km/h)

The 5-sigma upper limit has been about 16.0 mag
The message may be cited.