{
  "bibcode": "2008GCN..8754....1Y",
  "body": "F. Yuan (U Mich), E.S. Rykoff (UCSB), report on behalf of the ROTSE  \ncollaboration:\n\nROTSE-IIIc, located at the H.E.S.S. site at Mt. Gamsberg, Namibia,  \nresponded to GRB 081230 (Swift trigger 338633). The first image was at  \n20:47:53.4 UT, 700.8 s after the burst (8.4 s after the GCN notice  \ntime). The unfiltered images are calibrated relative to USNO A2.0. We  \ndetect a 19.1 magnitude, steady source in the XRT error box with  \ncoordinates:\n\n      02:29:19.35      -25:08:49.22    (J2000), with positional  \nuncertainty of 1\" or better\n\nstart UT    \tmag     mlim(of image)\n----------------------------------\n20:49:23.0     19.1     19.2\n\n\nThis source is not visible in DSS (second epoch), 2MASS or the  \nMPChecker database.\n\nA jpeg image is available at http://www.rotse.net/images/gsb338633_3c021-030_key.jpg\n\nContinuing observations are in progress.",
  "circularId": 8754,
  "createdOn": 1230672041000,
  "email": "yuanfang@umich.edu",
  "subject": "GRB 081230: ROTSE-III Detection of Optical Counterpart",
  "submitter": "Fang Yuan at ROTSE  <yuanfang@umich.edu>",
  "eventId": "GRB 081230"
}