{
  "bibcode": "2017GCN.22055....1L",
  "body": "V. Lipunov, E. Gorbovskoy, N.Tyurina, V.Kornilov, D.Kuvshinov, P.Balanutsa, \nA.Kuznetsov, V.V.Chazov, D. Vlasenko, I.Gorbunov, A.V.Krylov\nLomonosov Moscow State University,\nSternberg Astronomical Institute, Moscow State University\n\nR. Podesta, Carlos Lopez and F. Podesta\nObservatorio Astronomico Felix Aguilar (OAFA)\n\nHugo Levato and Carlos Saffe\nInstituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE)\n\nR. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres\nThe Instituto de Astrofisica de Canarias\n\n\nK. Ivanov, O. Gres, N.M. Budnev, S. Yazev, O. Chuvalaev, V. Poleshchuk\nIrkutsk State University\n\nA. Tlatov, V.Senik, A.V. Parhomenko, D. Dormidontov\nKislovodsk Solar Station of the Pulkovo Observatory\n\nV. Yurkov, A. Gabovich, Yu. Sergienko\nBlagoveschensk Educational State University, Blagoveschensk\n\n\nD. Buckley, S. Potter, A. Kniazev, M. Kotze\nSouth African Astronomical Observatory\n\nMASTER II  robotic telescope (MASTER-Net: http://observ.pereplet.ru) \nlocated in OAFA was pointed to the  GRB171027A ( D'Avanzo et al., GCN \nCirc 22053 ) 26 sec after notice time \nand 71 sec after trigger time at 2017-10-27 08:24:17 UT. On our first (10s \nexposure)  set we haven`t found optical transient  within SWIFT error-box \n(ra=61.6708 dec=-2.60556 r=0.05). The 5-sigma upper limit has been about \n17.5 mag . This and next 2 images  are prompt optical limit because GRB \nduration is ~ 120 \nsec (D'Avanzo et al., GCN Circ 22053 )\n\n\n\nThe OT limit are:\n\n   ID       UT     Exp          Type             Limit\n\n103456  08:24:17   10      Alert (SWIFT)        17.5\n103463  08:24:17   70   SumAlert (SWIFT)        19.0\n103473  08:24:17  550   SumAlert (SWIFT)        20.0\n103457  08:25:09   20      Alert (SWIFT)        18.1\n103459  08:26:10   40\t   Alert (SWIFT)\t18.6\n103467  08:27:34  210   SumAlert (SWIFT)        19.5\n103460  08:27:34   50      Alert (SWIFT)        18.6\n103461  08:29:07   70      Alert (SWIFT)        18.9\n103462  08:31:00   90      Alert (SWIFT)        19.0\n103472  08:33:15  450   SumAlert (SWIFT)        19.9\n103464  08:33:15  120      Alert (SWIFT)        19.2\n103466  08:36:00  150      Alert (SWIFT)        19.2\n103468  08:39:15  180      Alert (SWIFT)        19.3\n103476  08:43:00  540   SumAlert (SWIFT)        19.5\n103470  08:43:00  180      Alert (SWIFT)        19.0\n103471  08:46:43  180      Alert (SWIFT)        18.8\n103474  08:50:25  180      Alert (SWIFT)        18.4\n103477  08:54:08  180      Alert (SWIFT)        18.1\n103478  08:57:53  180      Alert (SWIFT)        18.1\n\n\nThe observations made on zenit distance = 41 degrees, galaxy latitude b = \n-37 degree. The moon (45 % bright part) below the horizon (The altitude of \nthe Moon is -33 degree ). Observations started at twilight.\nThe sun  altitude  is -16.5 degree.\nThe object can be observed till sunrise at 2017-10-27 09:44:50\n\n\nThe message may be cited.",
  "circularId": 22055,
  "createdOn": 1509100083000,
  "email": "lipunov@xray.sai.msu.ru",
  "subject": "GRB 171027A: MASTER-OAFA (Argentina) early prompt optical observations",
  "submitter": "Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>",
  "eventId": "GRB 171027A"
}