GCN Circular 24655

V. Lipunov, E. Gorbovskoy, V.Kornilov, N.Tyurina, P.Balanutsa, A.Kuznetsov, 
V.Vladimirov, D. Vlasenko, D.Zimnukhov, V.Senik, T.Pogrosheva, D.Kuvshinov 
(Lomonosov Moscow State University, SAI, Physics Department),

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

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

R. Rebolo, M. Serra 
(The Instituto de Astrofisica de Canarias)

D. Buckley 
(South African Astronomical Observatory),

O.A. Gres, N.M. Budnev, O.Ershova 
(Irkutsk State University, API),

A. Tlatov, D. Dormidontov 
(Kislovodsk Solar Station of the Pulkovo Observatory),

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




MASTER-OAFA robotic telescope  (Global 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) started inspect of the LIGO/Virgo S190524q errorbox  164 sec after trigger time at 2019-05-24 04:54:50 UT, with upper limit up to  17.6 mag. The observations began at zenit distance = 110 deg. The sun  altitude  is -78.4 deg. 

The galactic latitude b = -60 deg., longitude l = 98 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/ligo_1.php?id=10440

We obtain a following upper limits.  

Tmid-T0  |      Date Time      |          Site       |             Coord (J2000)          |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________

     254 | 2019-05-24 04:54:50 |         MASTER-OAFA | ( 13h 56m 23.08s , +38d  4m 56.27s) |   C |   180 | 16.4 |        
     483 | 2019-05-24 04:59:24 |         MASTER-OAFA | ( 17h 59m 04.35s , - 4d 10m 41.43s) |   C |    90 | 17.6 |        
Filter C is a clear (unfiltred) band. 


The observation and reduction will continue. 
The message may be cited.