{
  "bibcode": "2008GCN..7570....1W",
  "body": "J. Wren, W.T. Vestrand, P.R. Wozniak, H. Davis\nof Los Alamos National Laboratory report:\n\nOur RAPTOR telescopes imaged the location of Swift trigger\n306754 (Pagani et al., GCN 7426).  We do not detect the optical\ncounterpart initially reported by Cenko et al. (GCN 7429).  The\nlocation of the counterpart was within the field of view of our\ncontinuous all-sky monitoring system.  We can place 5 sigma\nlimits at approximately magnitude 9.0 during the time period\nwithin 5 minutes both before and after the trigger.  Our\nnarrow-field instruments began observing the location at\n05:46:51.90 UTC, 69.8 s after the Swift trigger, but also did\nnot detect the counterpart.  The limiting magnitudes of our\nunfiltered observations when calibrated to the USNO-B1 R-band\nare given in the following table.\n\nt-mid(s)    exp(s)     mag     mag-err\n--------------------------------------------\n-19.18      10.0       9.0     5 sigma limit\n14.07       10.0       9.0     5 sigma limit\n72.35        5.0      16.9     5 sigma limit\n156.60      10.0      17.4     5 sigma limit\n423.25      30.0      18.0     5 sigma limit",
  "circularId": 7570,
  "createdOn": 1207687338000,
  "email": "jwren@nis.lanl.gov",
  "subject": "GRB 080319A: Early RAPTOR optical limits",
  "submitter": "James Wren at LANL  <jwren@nis.lanl.gov>",
  "eventId": "GRB 080319A"
}