TITLE: GCN CIRCULAR NUMBER: 25000 SUBJECT: LIGO/Virgo S190706ai Global MASTER-Net observations report DATE: 19/07/06 23:17:13 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs V. Lipunov, E. Gorbovskoy, V.Kornilov, N.Tyurina, P.Balanutsa, A.Kuznetsov, F.Balakin, V.Vladimirov, D. Vlasenko, I.Gorbunov, 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-IAC robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Spain (IAC Teide Observatory) started inspect of the LIGO/Virgo S190706ai errorbox 1152 sec after trigger time at 2019-07-06 22:45:53 UT, with upper limit up to 18.7 mag. The observations began at zenit distance = 107 deg. The sun altitude is -28.9 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=10450 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 1242 | 2019-07-06 22:45:53 | MASTER-IAC | ( 12h 3m 31.75s , +55d 17m 03.03s) | P| | 180 | 18.7 | 1242 | 2019-07-06 22:45:53 | MASTER-IAC | ( 12h 2m 12.80s , +55d 21m 21.28s) | P- | 180 | 18.7 | The observation and reduction will continue. The message may be cited.