TITLE: GCN CIRCULAR NUMBER: 25558 SUBJECT: GRB 190829A:: MASTER-net bright and decay OT detection DATE: 19/08/29 22:35:55 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs V. Lipunov, F.Balakin, E. Gorbovskoy, V.Kornilov, N.Tyurina, P.Balanutsa, A.Kuznetsov, 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-Kislovodsk robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (Lomonosov MSU, Kislovodsk Solar Station of Pulkovo observatory) was pointed to the SWIFT GRB190829.83 (trigger No 922968,Dichiara et al GCN 25552) errorbox 1215 sec after notice time and 1239 sec after trigger time at 2019-08-29 20:17:23 UT, with upper limit up to 18.6 mag. The observations began at zenit distance = 89 deg. The sun altitude is -36.2 deg. MASTER-SAAO robotic telescope located in South Africa (South African Astronomical Observatory) was pointed to the SWIFT GRB190829.83 errorbox 1215 sec after notice time and 6757 sec after trigger time at 2019-08-29 21:49:21 UT, with upper limit up to 17.3 mag. The observations began at zenit distance = 76 deg. The sun altitude is -64.5 deg. MASTER-Tavrida robotic telescope located in Russia (Lomonosov MSU, SAI Crimea astronomical station) was pointed to the SWIFT GRB190829.83 errorbox 1215 sec after notice time and 6766 sec after trigger time at 2019-08-29 21:49:30 UT, with upper limit up to 16.4 mag. The observations began at zenit distance = 79 deg. The sun altitude is -36.7 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/observ.php?id=1119490 MASTER-Kislovodsk auto-detection system discovered OT source at (RA, Dec) = 02h 58m 10.51s -08d 57m 27.2s on 2019-08-29.86841 UT. The OT unfiltered magnitude is 14.9m (limit 17.2m). The OT is seen in 12 images. The OT decay on ~2 magnitudes during first 2 hours of observations. So this OT could be a GRB 190829A optical counterpart. We have reference image without OT on 2014-11-20.85262 UT with unfiltered magnitude limit 20.7m.