{
  "bibcode": "2023GCN.34483....1M",
  "createdOn": 1692414758418,
  "circularId": 34483,
  "eventId": "GRB 230818A",
  "submitter": "Moskvitin Alexander at SAO RAS <mosk@sao.ru>",
  "body": "A. S. Moskvitin, D. V. Oparin, V. S. Shergin and\nV. V. Komarov (SAO RAS), report on behalf of the GRB follow-up team.\n\nWe observed the field of GRB 230818A (Fermi GBM team, 34478;\nTohuvavohu et al., GCN 34479) with the 1-m telescope of SAO RAS\nZeiss-1000 equipped with the CCD photometer. We started observations\non August 18, 23:32:18 UT (~5 minutes after the trigger) and obtained\nmultiple images in BVRcIc bands (principally in Rc).\n\nWe clearly detected the OT (Lipunov et al., GCNs 34476, 34477,\n34481, 34482; Gompertz et al., GCN 34480) in our individual\nframes with the coordinates\nR. A. (J2000) = 19:03:33.11\nDecl. (J2000) = +40:53:49.2 (+/- 0\".5)\nand the following brightness:\nUT_start   exp, s    t_mid-T0, h   Rmag +/- err\n23:32:18    60       0.0872        17.79 +/- 0.06\n23:34:00    60       0.1156        18.07 +/- 0.06\n23:45:06   120       0.3089        19.18 +/- 0.08\n23:57:27   120       0.5147        19.68 +/- 0.10\n00:29:01   300       1.0658        20.52 +/- 0.13\n00:45:26   2 x 300   1.39333       20.48 +/- 0.09\n\nThis preliminary photometry is based on nearby USNO-B1 stars (R2 mag),\nthe magnitude is not corrected for MW extinction.\n\n",
  "submittedHow": "email-legacy",
  "subject": "GRB 230818A: SAO RAS Zeiss-1000 observations"
}