TITLE:   GCN CIRCULAR
NUMBER:  23027
SUBJECT: GRB 180723.13: MASTER optical observation of the short  Fermi GBM trigger number 554008254 
DATE:    18/07/24 10:31:46 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

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

D.Svinkin
Ioffe Institute, StPetersburg

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

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


MASTER-OAFA robotic telescope (MASTER-Net: http://observ.pereplet.ru, 
Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in 
Argentina (OAFA observatory of San Juan National University) was pointed 
to the  GRB180723.13 45 sec after notice time and 90 sec after trigger 
time at 2018-07-23 03:12:19 UT. On our first (20s exposure)  set we 
not found  optical transient within FERMI error-box (ra=136.058 dec=-64.17 
r=4.29) brighter then 15.8.


The coverage  map of the 3 sigms + sigma error box is available at 
http://master.sai.msu.ru/static/OT/MASTERmapFermi554008254.jpg

The observations made on zenit distance = 80 degrees, galaxy latitude b = 
-11 degree.
The moon (81 % bright part) is 58 degrees above the horizon. The distance 
between  moon and  object is 83
The sun  altitude  is -66.7 degree.
The object can be observed till sunrise at 2018-07-23 11:31:04 UT.

MASTER-OAFA robotic telescope  was pointed for second inspection
to the  GRB180723.13 1 days 20938 sec after notice time and 1 days 20938 
sec after trigger time at 2018-07-24 08:59:48 UT. We not found OT brighter 
then 18.1.

The message may be cited.