[vsnet-grb-info 16399] GRB 150403A: MASTER-net optical observation

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  17680
SUBJECT: GRB 150403A: MASTER-net optical observation
DATE:    15/04/06 17:24:35 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov at xray.sai.msu.ru>

E. Gorbovskoy, V. Lipunov,  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  GRB150403A (Lien et al. GCN 17665) 
20418 sec after notice time and 20434  sec (5.7h) after trigger time at 
2015-04-04 03:34:51 UT immediately after suitable weather condition came, 
in automatic mode. Observation lasted about 30 minutes, until the weather 
became bad again. We detect a faint OT on a Swift UVOT position (Kuin et al. GCN17673).
The estimated unfiltered magnitude is:

Date       time_start  T0-Tmid[s]  Expt.[s]   Mag  Coadd
2015-04-04 03:34:51.49  20840         720    19.2  4


Our unfiltered  band  is well described by a parity 0.8R+0.2B (USNO B1).

The message may be cited.