{
  "bibcode": "2011GCN.12014....1T",
  "body": "Andrea Tasselli (Lincoln, Lincolnshire, UK) reports to the AAVSO \nInternational High Energy Network the following optical observation of GRB \n110503A (GCN Circ. #11991, Stamatikos et al.):\n\nA. Tasselli (Lincoln, Lincolnshire, UK) reports a detection of GRB 110503A \nat an unfiltered, Sloan r-derived magnitude of cr = 19.1 +/- 0.1 on 2011 \nMay 05.9167 (JD 2455685.4167; midpoint of exposures), approximately 4 \nhours after the Swift trigger (GCN Circ. #11991, Stamatikos et al.). \nTasselli obtained 30 unfiltered images of 120 seconds exposure for a total \nof 3600 seconds.  Tasselli used a 0.2-meter Maksutov-Cassegrain (f/6.8) \nwith a Starlight SXV-H9 CCD camera.  Photometry of the OT was done using \nthe Iris photometry package with an ensemble of six SDSS stars:\n\nSDSS J085118.11+521119.2, r=14.756;\nSDSS J085118.96+521055.4, r=15.565;\nSDSS J085110.02+521104.6, r=17.177;\nSDSS J085119.59+521406.2, r=13.871;\nSDSS J085131.83+521343.8, r=13.893; and\nSDSS J085110.53+521301.8, r=17.749.\n\nThe position of the OT was measured using the Astrometrica package with 55 \nUCAC3 reference stars, and was found to be\n\n \tRA(J2000)  =  08 51 06.2\n \tDec(J2000) = +52 12 30\n\nin good agreement with other measurements.\n\nThe AAVSO International High Energy Network was made possible through \ngrants from the Charles Curry Foundation and NASA.",
  "circularId": 12014,
  "createdOn": 1305558417000,
  "email": "matthewt@aavso.org",
  "subject": "GRB 110503A optical observation",
  "submitter": "AAVSO GRB Network at AAVSO  <matthewt@aavso.org>",
  "eventId": "GRB 110503A"
}