{
  "bibcode": "2021GCN.29627....1L",
  "body": "V. Lipunov, E. Gorbovskoy, V.Kornilov, N.Tyurina, P.Balanutsa, A.Kuznetsov, F.Balakin, \nV.Vladimirov, D. Vlasenko, I.Gorbunov, D.Zimnukhov, V.Senik, T.Pogrosheva,\nD.Kuvshinov,  D. Cheryasov\n(Lomonosov Moscow State University, SAI, Physics Department),\n\nR. Podesta, C.Lopez, F. Podesta, C.Francile \n(Observatorio Astronomico Felix Aguilar OAFA),\n\nR. Rebolo, M. Serra \n(The Instituto de Astrofisica de Canarias),\n\nD. Buckley \n(South African Astronomical Observatory),\n\nO.A. Gres, N.M. Budnev, O.Ershova \n(Irkutsk State University, API),\n\nA. Tlatov, D. Dormidontov \n(Kislovodsk Solar Station of the Pulkovo Observatory),\n\nV. Yurkov, A. Gabovich, Yu. Sergienko \n(Blagoveschensk Educational State University)\n\n\n\n\nMASTER-SAAO robotic telescope  (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L)  located in South Africa (South African Astronomical Observatory) was pointed to the Swift GRB 210308A ( V. D'Elia et al., GCN 29619) errorbox  40899 sec after notice time and 40918 sec after trigger time at 2021-03-08 17:59:54 UT, with upper limit up to  13.9 mag. Observations started at twilight.  The observations began at zenith distance = 74 deg. The sun  altitude  is -12.2 deg. \n\nMASTER-IAC robotic telescope  located in Spain (IAC Teide Observatory) was pointed to the Swift GRB 210308A errorbox  55958 sec after notice time and 55976 sec after trigger time at 2021-03-08 22:10:53 UT, with upper limit up to  18.5 mag. The observations began at zenith distance = 48 deg. The sun  altitude  is -40.8 deg. \n\nThe galactic latitude b = -7 deg., longitude l = 164 deg.\n\n\nReal time updated cover map and OT discovered available here: \nhttps://master.sai.msu.ru/site/master2/observ.php?id=1563625\n\nWe obtain a following upper limits.  \n\nTmid-T0  |          Site       |Filt.| Expt. | Limit| Comment\n_________|_____________________|_____|_______|______|________\n\n   21950 |             MASTER- |   C |    60 | 18.0 |        \n   22210 |             MASTER- |   C |    60 | 15.8 |        \n   22945 |             MASTER- |   C |    60 | 12.6 |        \n   41008 |         MASTER-SAAO |   C |   180 | 13.9 |        \n   56067 |          MASTER-IAC |   C |   180 | 18.5 |        \nFilter C is a clear (unfiltred) band. \n\n\nThe observation and reduction will continue. \nThe message may be cited.",
  "circularId": 29627,
  "createdOn": 1615241891000,
  "email": "lipunov@xray.sai.msu.ru",
  "subject": "Swift GRB 210308A: Global MASTER-Net observations report",
  "submitter": "Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>",
  "eventId": "GRB 210308A"
}