TITLE:   GCN CIRCULAR
NUMBER:  23071
SUBJECT: Fermi Trigger 554765006: MASTER optical inspection
DATE:    18/08/01 15:18:58 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

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

D. Buckley,
South African Astronomical Observatory (SAAO)

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

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

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


MASTER-Kislovodsk robotic telescope (MASTER-Net: 
http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, 
vol. 2010, 30L) located in Russia (Pulkovo Solar Station) was pointed to 
the GRB180731.89 588 sec after trigger time and 32 after notice time at 
2018-07-31 21:33:15 UT . On our first (120s exposure)  set we do not found 
optical transients within Fermi-GBM error-box (ra=308.930 dec=20.600 
r=2.15) brighter then 18.7.

The observations made on zenit distance = 66.25 degrees, galaxy latitude b=
-12.19 degree.
The moon (86 % bright part) is 29 degrees above the horizon. The distance 
between  moon and  object is 53
The sun  altitude  is -27.94 degree.
The errorbox observed till sunrise 2018-08-01 00:59:46

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 
GRB180731.89 589 sec after trigger time and 33 after notice time at 
2018-07-31 21:33:16 UT . On our first (120s exposure)  set we do not found 
optical transients within Fermi-GBM error-box (ra=308.930 dec=20.600 
r=2.15) brighter then 19.3.

The observations made on zenit distance = 35.02 degrees, galaxy latitude b=
-12.19 degree.
The moon (86 % bright part) is 28 degrees above the horizon. The distance 
between  moon and  object is 53
The sun  altitude  is -68.99 degree.
The errorbox observed till 2018-07-31 22:00:32

MASTER-Tavrida robotic telescope (MASTER-Net: http://observ.pereplet.ru, 
Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in 
Russia (SAI Crimea astronomical station) was pointed to the GRB180731.89 
595 sec after trigger time and 39 after notice time at 2018-07-31 21:33:22 
UT.  On our first (120s exposure)  set we do not found  optical transients 
within Fermi-GBM error-box (ra=308.930 dec=20.600 r=2.15) brighter then 
19.4.

The observations made on zenit distance = 65.81 degrees, galaxy latitude b=
-12.19 degree.
The moon (86 % bright part) is 23 degrees above the horizon. The distance 
between  moon and  object is 53
The sun  altitude  is -26.99 degree.
The errorbox observed till 2018-07-31 21:42:34

The coverage  map of the 3 sigms + sigma error box is available at
master.sai.msu.ru/static/OT/MASTERFermi554765006.jpg

The visibility GRB error box (coord:308.930, 20.600 error_box: 2.15)
at trigger time at different MASTER sites:

obj:  65.57 sun: -26.82 - Tavrida (Crimea, Russia)
obj:  39.65 sun: -17.94 - IAC, Teide, (Tenerife, Spain)
obj:  34.35 sun: -67.32 - SAAO (Sutherland, SA)
obj:  66.63 sun: -28.05 - Kislovodsk (Russia)
obj:  50.44 sun: -13.11 - Ural(Kourovka, Russia)
obj:  31.75 sun: -1.44  - Tunka (near Baykal Lake, Russia)
obj:  16.42 sun:  12.03 - Amur(Blagoveschensk)
obj: -25.50  sun:  6.26 - OAFA (Argentina)


The message may be cited.