{
  "bibcode": "2008GCN..8170....1Y",
  "body": "F. Yuan (U Mich), W. Rujopakarn (Steward), H. Swan (U Mich), D.A.  \nSmith (Guilford), T. Guver (U Arizona) report on behalf of the ROTSE  \ncollaboration:\n\nROTSE-IIId, located at the Turkish National Observatory at  \nBakirlitepe, Turkey, responded to GRB 080903 (Swift trigger 323542;  \nGrupe et al., GCN 8169), producing images beginning 6.7 s after the  \nGCN notice time. An automated response took the first image at  \n01:12:47.7 UT, 24.4 s after the burst, and during the gamma-ray  \nemission, under fair conditions. We took 10 5-sec, 10 20-sec and 30 60- \nsec exposures. These unfiltered images are calibrated relative to USNO  \nA2.0 (R). Imaging is on going.\n\nComparison to the DSS (second epoch) reveals no new sources within the  \n3-sigma Swift/BAT error circle or the XRT error circle, for both  \nsingle images and coadding into sets of 10. Individual images have  \nlimiting magnitudes ranging from 16.5-17.7; we set the following  \nspecific limits.\n\nstart UT       end UT      t_exp(s)   mlim   t_start-tGRB(s)  Coadd?\n--------------------------------------------------------------------\n01:12:47.7   01:14:55.9       128     17.7           24.4       Y\n01:15:04.6   01:19:42.4       277     18.3          161.3       Y",
  "circularId": 8170,
  "createdOn": 1220407922000,
  "email": "yuanfang@umich.edu",
  "subject": "GRB 080903: ROTSE-III Optical Limits",
  "submitter": "Fang Yuan at ROTSE  <yuanfang@umich.edu>",
  "eventId": "GRB 080903"
}