{
  "bibcode": "2021GCN.30226....1I",
  "body": "M. Ibrahimov, M. Nalivkin, I. Nikolenko (all from INASAN, \nMoscow, Russia) and O. Pons (IGA, Havana, Cuba) report on \nbehalf of a larger team:\n\n\n\nUsing Zeiss 1m telescope and 4K FLI PL16803 CCD of Simeiz \nObserbatory (Collective Using Center of INASAN), we \nobserved the field of GRB 210610B (Page et al., GCN \n30170). 15x120sec images were acquired through Bessel R \nfilter on 2021-06-11/00:03:07 UT (midpoint time, 4.18 \nhours after the trigger) with a total exposure time of \n1800 sec.\n\n\n\nOptical afterglow (for a list of the most full references \nsee e.g. Hosokawa et al., GCN 30220 and Anandagoda et al., \nGCN 30221) was clearly seen in all 15 individual R images.\n\n\n\nPhotometry of the optical afterglow using stacked R-image \ncalibrated against USNO-B1 R1-mag of 2 nearby stars, \nresulted in: R = 17.61 +/- 0.02 mag.\n\n\n\nResearch was supported by Project No. RFMEFI61319X0093 \n(Russian Ministry of Science and High Education, Agreement \nNo. 075-15-2019-1716 by 2019 Nov 20) and Project No. \n19-29-11013 (Russian Foundation of Fundamental \nInvestigation, Agreement No. 19-29-11013\\20 by 2021 Jan \n21).",
  "circularId": 30226,
  "createdOn": 1623525374000,
  "email": "mansur@inasan.ru",
  "subject": "GRB 210610B: optical photometry of afterglow at INASAN/Simeiz",
  "submitter": "Mansur Ibrahimov at INASAN  <mansur@inasan.ru>",
  "eventId": "GRB 210610B"
}