[vsnet-grb-info 21011] GRB180809B: MASTER OT observation

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  23109
SUBJECT: GRB180809B: MASTER OT observation
DATE:    18/08/10 00:26:43 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov at xray.sai.msu.ru>

V. Lipunov, N.Tiurina, E. Gorbovskoy,
V.Kornilov, A.Kuznetsov, V.Chazov, I.  Gorbunov,
D.Zimnukhov, D.Kuvshinov, P.Balanutsa, V.Vladimirov, D. Vlasenko
Lomonosov Moscow State University,SAI

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

D. Buckley,
South African Astronomical Observatory (SAAO)

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

R. Podesta, F. Podesta, C. Lopez, C.Francile
Observatorio Astronomico Felix Aguilar (OAFA)

H.Levato,
Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE)

O. Gres, N.M.Budnev , Yu.Ishmuhametova
Irkutsk State University (ISU)

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


MASTER-SAAO robotic telescope (MASTER-Net: http://observ.pereplet.ru, 
Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in 
South Africa (South African Astronomical Observatory)
was pointed to the   GRB180809B(Moss et al. GCN 23105) 16 sec after notice 
time and 42 sec after trigger time at 2018-08-09 20:30:40 UT.
On our 3-th (20s exposure)  set , obtained 101 sec after tigger time at 2018-08-09 20:31:39 UT,
we  found 1 optical transient  within SWIFT error-box


  T-Tmid      Date      Time       Expt.        Ra                Dec           mag
---------|---------------------|-------|-----------------|-----------------|-------
      111   2018-08-09 20:31:39      20    (19h 58m 48.0s , -15d 17m 57.1s)     16.87

also detected by Swift UVOT (Moss et al. GCN 23105)

The 5-sigma upper limit has been about 17.4mag
The message may be cited.