{
  "bibcode": "2010GCN.11213....1S",
  "body": "Stefano Sposetti (Gnosca, Switzerland) reports to the AAVSO International \nHigh Energy Network the following optical observations of GRB 100901A (GCN \n#11159, Immler et al.):\n\nStefano Sposetti reports a clear detection of the optical afterglow of GRB \n100901A (GCN #11159, Immler et al., and many subsequent reports), and \nobvious fading over the four hour span of observations.  The afterglow was \nobserved unfiltered (R-band zero point) beginning at 23:25UT on 2010 \nSeptember 01 (approximately 10 hours post-burst), and continuing to 03:50 \nUT on 2010 September 02.  Observations were made using an SBIG ST8XE CCD \nattached to a 0.4-m Newtonian sited in Gnosca, Switzerland.  A total of \nsixty 30-second integrations and 215 60-second integrations were obtained. \nAn ensemble of stars from the USNO-A2.0 catalog were used for the \nmagnitude comparison. The frames were co-added into sixteen frames of \n15-minutes duration each, to enable time-series photometry. \nSignal-to-noise in all of the images was between 24 and 52.\n\nThe following time-series data were derived:\n\n     date      \tmag(CR)\nSept 1.98105 \t17.43\nSept 1.99242 \t17.50\nSept 2.00391 \t17.49\nSept 2.01520 \t17.53\nSept 2.02619 \t17.66\nSept 2.03711 \t17.67\nSept 2.04803 \t17.57\nSept 2.05896 \t17.63\nSept 2.07011 \t17.66\nSept 2.08135 \t17.72\nSept 2.09257 \t17.83\nSept 2.10413 \t17.79\nSept 2.11637 \t17.80\nSept 2.12767 \t17.79\nSept 2.13897 \t17.85\nSept 2.15026 \t17.91\n\nThe AAVSO High Energy Network was made possible through grants from the\nCharles Curry Foundation and NASA.",
  "circularId": 11213,
  "createdOn": 1283694879000,
  "email": "matthewt@aavso.org",
  "subject": "Optical observations of GRB 100901A",
  "submitter": "AAVSO GRB Network at AAVSO  <matthewt@aavso.org>",
  "eventId": "GRB 100901A"
}