[vsnet-grb-info 16940] GRB 150831B: MASTER-IAC early optical observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  18221
SUBJECT: GRB 150831B: MASTER-IAC early optical observations 
DATE:    15/09/01 07:28:29 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov at xray.sai.msu.ru>

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

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

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

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

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

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

V.Krushinski, I.Zalozhnih
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; 
http://161.72.133.2/) 
located in IAC was pointed to the  GRB150831B 24 sec after notice time 
and 56 sec after trigger time at 2015-08-31 22:20:23 UT (Swift: Marshall 
et al., GCN 18215; and Fermi:  Veres and C. Meegan, GCN 18220) .
On our first (10s exposure)  set (two polarisations) we  did  not found 
optical transient 
within SWIFT  error-box  (Marshall et al., GCN 18215; Evans et al., GCN 
18217) brighter then 16.3. The observations were stoped by beautifull 
Canarian sun rise ( see 
http://observ.pereplet.ru/images/webcam01spt2015.jpg ) at 2015-09-01 
06:37:36 UT.


Pro.type	Date time + -	     Exp.time	Limit	Filt.	Tube.
                    Start
Alert      2015-08-31 22:20:23   	10	16.3	P	WEST
Alert 	   2015-08-31 22:20:23	        10	15.6	P	EAST
Alert 	   2015-08-31 22:21:07	        20	16.4	P	WEST
Alert 	   2015-08-31 22:21:07	        20	15.9	P	EAST
Alert 	   2015-08-31 22:21:37	        30	16.8	P	WEST
Alert 	   2015-08-31 22:21:37	        30	16.2	P	EAST
Alert 	   2015-08-31 22:22:18	        30	0.0*	P	WEST 
Alert 	   2015-08-31 22:22:18	        30	16.2	P	EAST
Alert 	   2015-08-31 22:22:57	        40	16.9	P	WEST
Alert 	   2015-08-31 22:22:57	        40	16.3	P	EAST
Alert 	   2015-08-31 22:23:47	        50	17.0	P	WEST
Alert 	   2015-08-31 22:23:47	        50	16.5	P	EAST
Alert 	   2015-08-31 22:24:47	        60	17.0	P	WEST
Alert 	   2015-08-31 22:24:47	        60	16.5	P	EAST
Alert 	   2015-08-31 22:25:56	        80	17.2	P	WEST
Alert 	   2015-08-31 22:25:56	        80	16.6	P	EAST
Alert 	   2015-08-31 22:27:26	        100	17.2	P	WEST
Alert 	   2015-08-31 22:27:26	        100	16.6	P	EAST
Alert 	   2015-08-31 22:29:17	        120	17.3	P	WEST
Alert 	   2015-08-31 22:29:17 	        120	16.6	P	EAST
Alert 	   2015-08-31 22:31:27	        140	17.3	P	WEST
Alert 	   2015-08-31 22:31:27	        140	16.7	P	EAST
Alert 	   2015-08-31 22:33:57	        170	17.3	P	WEST
Alert 	   2015-08-31 22:33:57	        170	16.7	P	EAST

* - no stars 
Our server hase a lot of job in Milky Way star dust now.

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