{
  "bibcode": "2018GCN.23113....1T",
  "body": "N.Tiurina, V. Lipunov, E. Gorbovskoy,\nV.Kornilov, A.Kuznetsov, V.Chazov, I.  Gorbunov,\nD.Zimnukhov, D.Kuvshinov, P.Balanutsa, V.Vladimirov, D. Vlasenko\nLomonosov Moscow State University,SAI\n\nR. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres\nThe Instituto de Astrofisica de Canarias (IAC)\n\nD. Buckley,\nSouth African Astronomical Observatory (SAAO)\n\nA. Tlatov, V.Senik, D. Dormidontov\nKislovodsk Solar Station of the Pulkovo Observatory\n\nR. Podesta, F. Podesta, C. Lopez, C.Francile\nObservatorio Astronomico Felix Aguilar (OAFA)\n\nH.Levato,\nInstituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE)\n\nO. Gres, N.M.Budnev , Yu.Ishmuhametova\nIrkutsk State University (ISU)\n\nA. Gabovich, V. Yurkov, Yu. Sergienko\nBlagoveschensk Educational State University (BSPU)\n\n\nWe have already reported the observation of the optical transient GRB \n180809B (Moss et al., GCN # 23105) by one of the telescopes of the MASTER \nGlobal Network (Lipunov et al., GCN 23109).\n\nHere we report on the triple independent, automatic detection of the \noptical transient (also found by Swift UVOT (Moss et al., GCN 23105)). The \nrelatively later guidance of the three MASTER robotic telescopes is due to \nthe fact that the first socket message did not indicate the time of the \ntrigger. As a result, everyone went to the CALET Alert (trig \nnumber 1217881726) with poor defined coordinates. \nNevertheless, we were able to obtain detailed light curves \nwith a maximum in 4 polarizations.\n\n\nMASTER-SAAO robotic telescope (MASTER-Net: http://observ.pereplet.ru, \nLipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in \nSouth Africa (South African Astronomical Observatory) was pointed to the \nGRB180809.85 16 sec after notice time and 111 sec after trigger time at \n2018-08-09 20:30:39 UT. On our 1-th (10s exposure)  set in two \npolarizations (/\\), obtained 111 \nsec after tigger time at 2018-08-09 20:30:39 UT, we  found 1 optical transient \nwithin SWIFT error-box (ra=299.7 dec=-15.2989 r=0.05) brighter then 17.4.\n\n\n  T-Tmid      Date   Time       Expt.        Ra                Dec        Mag\n    s                 UT         s\n-------|--------------------|-------|-----------------|---------------|-------\n   116    2018-08-09 20:30:39    10    (19h 58m 48.0s , -15d 17m 57.1s)   16.5\n\nThe 5-sigma upper limit has been about 17.9 mag\n\n\nThe observations started on zenit distance = 21 deg., galactic latitude b \n= -22 deg. The moon ( 4 % bright part) was below the horizon (The altitude \nof the  Moon = -75 deg ). The sun  altitude  = -56.3 degree. The object \ncan be observed till 2018-08-10 04:03:58 UT.\n\n\nMASTER-Tavrida robotic telescope (MASTER-Net: http://observ.pereplet.ru, \nLipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in \nRussia (Lomonosov MSU, SAI Crimea astronomical station) was pointed to the \nGRB180809.85 35 sec after notice time and 133 sec after trigger time at \n2018-08-09 20:31:01 UT. On our first (10s \nexposure)  set we  found 1 optical transient within SWIFT error-box\n(ra=299.7 dec=-15.2989 r=0.05) brighter then 17.9:\n\n\nT-Tmid   Date      Time       Expt.        Ra                Dec           Mag\n   s                UT         s\n------|--------------------|-------|-----------------|-----------------|-------\n  138    2018-08-09 20:31:01    10    ( 19h 58m 48.0s , -15d 17m 56.5s)    16.8\n\nThe 5-sigma upper limit has been about 17.9 mag\n\n\nThe observations made on zenit distance = 60 degrees, galaxy latitude b = -22 degree.\nThe moon ( 4 % bright part) below the horizon (The altitude of the Moon is \n-25 degree ). The sun  altitude  is -27.0 degree.\nThe object can be observed till 2018-08-10 01:29:20.\n\n\nMASTER-IAC robotic telescope (MASTER-Net: http://observ.pereplet.ru, \nLipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in \nSpain (IAC Teide Observatory) was pointed to the  GRB180809.85 120 sec \nafter notice time and 147 sec after trigger time at 2018-08-09 20:31:15 \nUT in two polarizations (|-). \nOn our first  set, obtained   we  found 1 optical transient within SWIFT \nerror-box (ra=299.7 dec=-15.2989 r=0.05):\n\n\n  T-Tmid      Date      Time       Expt.        Ra                Dec           Mag\n---------|---------------------|-------|-----------------|-----------------|-------\n   152      2018-08-10 20 31 15     20   ( 19h 58m 43.3s , -15d 20m 37.9s)     15.5\n\nThe 5-sigma upper limit has been about 16.0 magThe message may be cited.\n\nThe observations made on zenit distance = 44 degrees, galaxy latitude b = \n-22 degree. The moon ( 3 % bright part) below the horizon (The altitude of \nthe Moon is  -41 degree ). The sun  altitude  is  -9.1 deg.\nThe object can be observed till 2018-08-10 05:19:05 UT.\n\n\nThe message may be cited.",
  "circularId": 23113,
  "createdOn": 1533892036000,
  "email": "lipunov@xray.sai.msu.ru",
  "subject": "GRB180809B: MASTER  Triple Independent Automatic OT Detection",
  "submitter": "Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>",
  "eventId": "GRB 180809B"
}