{
  "bibcode": "2021GCN.30518....1B",
  "body": "S. Belkin (IKI),  A. Novichonok (Petrozavodsk State University, KIAM), \n  A. Pozanenko (IKI), A. Zhornichenko (KIAM),  N. Pankov (HSE)  report \non behalf of IKI GRB FuN:\n\nWe observed the field of  GRB 210724A (D'Avanzo et al. GCN 30497) with \nZeiss-1000 telescope of Koshka observatory starting on July 24 (UT) \n20:39:32. We do not detect any object XRT error circle (D'Avanzo et al. \nGCN 30497). We also not detect the object at the position of the \nafterglow candidate (Ugarte Postigo et al., GCN 30511).\n\nPreliminary photometry of the field is following\n\nDate       UT start   t-T0       Filter Exp.    OT   Err.  UL(3sigma)\n                       (mid, days)        (s)\n\n2021-07-24 20:39:32   0.024919    R     21*60   n/d  n/d   18.6\n\nThe photometry is based on the nearby USNO-B1.0 stars\nUSNO-B1.0_id R2\nUSNO-B1.0_id R2\n0837-0267865 15.24\n0836-0268753 16.95\n0837-0267827 15.54",
  "circularId": 30518,
  "createdOn": 1627301652000,
  "email": "apozanen@iki.rssi.ru",
  "subject": "GRB 210724A: Zeiss-1000 of Koshka observatory, optical upper limit",
  "submitter": "Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>",
  "eventId": "GRB 210724A"
}