{
  "createdOn": 1789984776620,
  "circularId": 45677,
  "body": "M. Segura,  F. Podesta, R.Podesta, E. Gonzalez (Observatorio Astronomico Felix Aguilar (OAFA)\n\nV.Lipunov, E.Gorbovskoy, A.Kuznetsov, K.Zhirkov, I.Panchenko, N.Tiurina, P.Balanutsa, V.Topolev, D.Vlasenko,  \nG.Antipov,  A.Sankovich,  Yu.Tselik, Ya..Kechin, V.Senik, A.Chasovnikov, K.Labsina (Lomonosov MSU)\n\nD.Buckley (SAAO),\n\nA. Gabovich, V.Yurkov (Blagoveschensk Educational StateUniversity)\nA.Sosnovskij (Lomonosov MSU)\n\nA. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory)\n\nL.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez,\nA.R.Corella, L.H.Rodriguez (INAOE, Guillermo Haro Astrophysics Observatory)\n\nR.Rebolo (The Instituto de Astrofisica de Canarias)\n\nO.Gress, N.Budnev(ISU)\n\n\nMASTER-OAFA robotic telescope  [1]  located in Argentina (OAFA observatory of San Juan National University) was pointed to the Swift GRB 260921A ( K. L. Page et al., GCN 45676) errorbox  58 sec after notice time and 80 sec after trigger time at 2026-09-21 09:30:32 UT, with upper limit up to  15.5 mag. Observations started at twilight.  The observations began at zenith distance = 76 deg. The sun  altitude  is -12.8 deg. \n\nThe galactic latitude b = 39 deg., longitude l = 233 deg.\n\n\nReal time updated cover map and OT discovered available here: \nhttps://master.sai.msu.ru/site/master2/observ.php?id=3508447\n\nWe obtain a following upper limits.  \n\nTmid-T0  |          Site       |Filt.| Expt. | Limit| Comment\n_________|_____________________|_____|_______|______|________\n\n      91 |         MASTER-OAFA |   C |    20 | 15.2 |        \n     117 |         MASTER-OAFA |   C |    20 | 15.3 |        \n     148 |         MASTER-OAFA |   C |    30 | 15.3 |        \n     183 |         MASTER-OAFA |   C |    30 | 15.2 |        \n     224 |         MASTER-OAFA |   C |    40 | 15.5 |        \n     275 |         MASTER-OAFA |   C |    50 | 15.1 |        \n     337 |         MASTER-OAFA |   C |    60 | 15.3 |        \n     407 |         MASTER-OAFA |   C |    70 | 14.9 |        \n     494 |         MASTER-OAFA |   C |    90 | 14.6 |        \n     600 |         MASTER-OAFA |   C |   110 | 15.3 |        \nFilter C is a clear (unfiltred) band. \n\n\nThe observation and reduction will continue. \nThe message may be cited.\n\n[1] - V.M. Lipunov, V.G. Kornilov, E.S. Gorbovskoy, N.A. Tiurina & A.S.Kuznetsov, 2023,  Astronomical Robotic Networks and Operative Multichanel Astrophysics, Lomonosov MSU PRESS, 591pp.\nhttp : // www.pereplet.ru/lipunov/625.html\n",
  "eventId": "GRB 260921A",
  "submitter": "Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>",
  "submittedHow": "email",
  "subject": "Swift GRB 260921A: Global MASTER-Net observations report"
}