{
  "bibcode": "2021GCN.29603....1H",
  "body": "Veli-Pekka Hentunen and Markku Nissinen (Taurus Hill Observatory, Varkaus, \n\nFinland) report:\n\n \n\nWe have detected GRB 210306A optical afterglow using iTelescope T24 \n\n(0.61-m f/6.5 + CCD) telescope in Sierra Remote Observatory  (Auberry, \n\nCalifornia, USA). The observations were started at 2021-03-06 05:02:41 (UT).\n\nWe used Luminance filter and 300 sec exposures. \n\n \n\nThe afterglow was detected at the position RA 08 39 50.11 DEC +60 12 18.8.  \n\nThe following magnitudes were measured from comparison of  a nearby star\n\n(r = 16.974) from Pan-STARRS DR1 catalogue (Chambers et al., 2016):\n\n \n\nTmid (h:min:sec)+T0    Mag     Mag_err            \n\n01:11:12                      18.08   0.08\n\n01:16:55                      17.97   0.06\n\n01:22:47                      18.13   0.07\n\n02:06:55                      18.41   0.10\n\n02:14:53                      18.44   0.09\n\n02:18:53                      18.52   0.10\n\n02:24:37                      18.63   0.10\n\n03:03:34                      18.82   0.11\n\n03:09:13                      18.85   0.11\n\n03:20:45                      18.87   0.12\n\n03:26:56                      18.91   0.12\n\n03:32:55                      18.84   0.13\n\n04:33:44                      19.33   0.19\n\n04:39:39                      19.22   0.18\n\n05:03:57                      19.33   0.21\n\n05:27:40                      19.61   0.38\n\n \n\nMagnitudes were not corrected for galactic extinction.\n\n \n\nURL link for the L filter 300s image:\n\nhttps://www.kassiopeia.net/2021/03/06/grb-210306a-havainto/",
  "circularId": 29603,
  "createdOn": 1615040599000,
  "email": "veli-pekka.hentunen@kassiopeia.net",
  "subject": "GRB 210306A: iTelescope T24 optical observations",
  "submitter": "Veli-Pekka Hentunen at Taurus Hill Obs,A95  <veli-pekka.hentunen@kassiopeia.net>",
  "eventId": "GRB 210306A"
}