TITLE: GCN CIRCULAR NUMBER: 22972 SUBJECT: GRB 180718A: MASTER optical observation DATE: 18/07/20 13:00:27 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs D. Vlasenko, N.Tiurina, E. Gorbovskoy, V. Lipunov, V.Kornilov, A.Kuznetsov, V.Chazov, I. Gorbunov, D.Zimnukhov, D.Kuvshinov, P.Balanutsa, V.Vladimirov Lomonosov Moscow State University,SAI 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 Global Robotic Net ( Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) inspected GRB180718A (Svinkin et al. GCN22959 ; Fermi trigger 553571869 at 2018-07-18 01:57:44.60 UT , Hamburg et al. GCN22960; Swift BAT position RA,Dec2000= 22h 24m 04.6s +02d 47' 23.3" (Svinkin et al GCN22959; Evans et al. GCN22963) MASTER-Kislovodsk robotic telescope (MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (Pulkovo Solar Station) was pointed to the GRB180718A (D. Svinkin et al., GCN Circ #22959) 60867 sec after trigger time at 2018-07-18 18:52:12 UT . On our first (180s exposure) set we do not found optical transients within Swift error-box (ra=336.019 dec=2.790 r=0.05) brighter then 18.5. The observations made on zenit distance = 13.51 degrees, galaxy latitude b = -43.86 degree. The moon (39 % bright part) is 15 degrees above the horizon. The distance between moon and object is 142 The sun altitude is -17.5 degree. The errorbox observed 2 nights till 2018-07-19 22:23:00 MASTER-Tavrida robotic telescope (MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (SAI Crimea astronomical station) was pointed to the GRB180718A (D. Svinkin et al., GCN Circ #22959) 63704 sec after trigger time at 2018-07-18 19:39:29 UT . On our first (180s exposure) set we do not found optical transients within Swift error-box (ra=336.019 dec=2.790 r=0.05) brighter then 18.6. The observations made on zenit distance = 15.68 degrees, galaxy latitude b = -43.86 degree. The moon (39 % bright part) is 13 degrees above the horizon. The distance between moon and object is 142 The sun altitude is -18 degree. The errorbox observed 2 nights till 2018-07-19 21:25:48 MASTER-IAC robotic telescope (MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Spain (IAC Teide Observatory) was pointed to the GRB180718A (D. Svinkin et al., GCN Circ #22959) 161995 sec after trigger time at 2018-07-19 22:57:40 UT . On our first (180s exposure) set we do not found optical transients within Swift error-box (ra=336.019 dec=2.790 r=0.05) brighter then 17.5. The observations made on zenit distance = 18.52 degrees, galaxy latitude b = -43.86 degree. The moon (39 % bright part) is 25 degrees above the horizon. The distance between moon and object is 128 The sun altitude is -11.80 degree. The errorbox observed till 2018-07-19 23:53:58 The visibility GRB error box (coord: 336.019 2.790 error_box: 0.05) at trigger time at different MASTER sites: obj: 43.32 sun: -3.21 - Tavrida (Crimea, Russia) obj: 53.60 sun: -39.34 - IAC, Teide, (Tenerife, Spain) obj: 53.56 sun: -45.24 - SAAO (Sutherland, SA) obj: 40.32 sun: 1.49 - Kislovodsk (Russia) obj: 23.50 sun: 16.36 - Ural(Kourovka, Russia) obj: 0.76 sun: 41.53 - Tunka (near Baykal Lake, Russia) obj: -14.45 sun: 55.06 - Amur(Blagoveschensk) obj: 6.93 sun: -51.86 - OAFA (Argentina) The message may be cited.