TITLE: GCN CIRCULAR NUMBER: 24921 SUBJECT: LIGO/Virgo S190630ag Global MASTER-Net observations report DATE: 19/06/30 19:37:18 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-Tavrida robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (Lomonosov MSU, SAI Crimea astronomical station) started inspect of the LIGO/Virgo S190630ag errorbox 387 sec after trigger time at 2019-06-30 18:58:32 UT, with upper limit up to 18.6 mag. Observations started at twilight. The observations began at zenit distance = 113 deg. The sun altitude is -12.6 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=10447 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 477 | 2019-06-30 18:58:32 | MASTER-Tavrida | ( 18h 46m 19.53s , + 0d 58m 53.19s) | C | 180 | 18.3 | 478 | 2019-06-30 18:58:32 | MASTER-Tavrida | ( 18h 45m 05.49s , + 0d 56m 03.34s) | C | 180 | 18.4 | 717 | 2019-06-30 19:02:32 | MASTER-Tavrida | ( 10h 51m 18.45s , +16d 5m 22.47s) | C | 180 | 17.9 | 938 | 2019-06-30 19:06:12 | MASTER-Tavrida | ( 10h 57m 51.75s , +22d 5m 24.42s) | C | 180 | 18.6 | 938 | 2019-06-30 19:06:12 | MASTER-Tavrida | ( 10h 59m 12.44s , +22d 9m 14.84s) | C | 180 | 17.2 | 1158 | 2019-06-30 19:09:52 | MASTER-Tavrida | ( 10h 49m 08.87s , +20d 5m 32.01s) | C | 180 | 13.6 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited.