{
  "bibcode": "2021GCN.29845....1L",
  "body": "V. Lipunov, V.Kornilov, E.Gorbovskoy, A.Chasovnikov, P.Balanutsa,V.Vladimirov, A.Kuznetsov,\nD. Vlasenko, N.Tiurina, I.Gorbunov,  D.Zimnukhov, V.Senik,V.Topolev,\nF.Balakin, D.Cheryasov (Lomonosov Moscow State University,SAI, PhysicsDepartment),\nD. Buckley (South African Astronomical Observatory),\nO.A. Gres, N.M. Budnev (Irkutsk State University, API),\nR. Podesta, C.Lopez, F. Podesta, C.Francile (Observatorio Astronomico Felix Aguilar OAFA),\nR. Rebolo, M. Serra(The Instituto de Astrofisica de Canarias),\nA. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory),\nA. Gabovich, V.Yurkov (Blagoveschensk Educational StateUniversity)\n\nMASTER Global robotic net (MASTER-Net:http://observ.pereplet.ru Lipunov etal.,2010,Advances in Astronomy,2010,30L)\nstarted GRB 210420B (Swift trigger 1044382 Moss  et al. GCN 29844,Ttrigger=2021-04-20 18:20-50UT)\nat MASTER-Kislovodsk at 2021-04-20 20:01:24UT\n\nThere is optical counterpart (changing)\nat RA,Dec(2000)= 16h 57m 18.23s ,+42d 34m 11s.8 +-1\"\nMASTER OT J165718.23+423411.8\nfound by MASTER auto-detection system \nwith m_OT~19 at 2021-04-20 20:05:23TU\n\nObservation started at alert altitude 45deg.",
  "circularId": 29845,
  "createdOn": 1618950961000,
  "email": "lipunov@xray.sai.msu.ru",
  "subject": "GRB 210420B: MASTER optical counterpart detection",
  "submitter": "Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>",
  "eventId": "GRB 210420B"
}