{
  "bibcode": "2017GCN.21027....1K",
  "body": "Klotz A., Turpin D., Atteia J.L. (CNRS-OMP-IRAP),\nBoer, M., Laugier, R. (CNRS-ARTEMIS),\nGendre B. (UVI - Etelman Obs.) report:\n\nWe imaged the field of the trigger 748858 detected by SWIFT\nwith the TAROT robotic telescope (D=25cm)\nlocated at the European Southern Observatory,\nLa Silla observatory, Chile.\n\nThe observations started 91.6s after the GRB trigger\n(14.7s after the notice). The elevation of the field decreased from\n22 degrees above horizon and weather conditions\nwere good.\n\nThe first image is trailed with a duration of 60.0s\n(see the description in Klotz et al., 2006, A&A 451, L39).\nWe do not detect any OT in the BAT error box from\nSiegel et al. (GCN 21011) and by Sakamoto et al. (GCN 21017)\nwith a limiting magnitude of:\nt0+92s to t0+152s : Rlim = 18.0\n\nThe second image is 30.0s exposure in tracking mode:\nt0+165s to t0+195s : Rlim = 18.2\n\nWe co-added a series of exposures:\nt0+165s to t0+455s : Rlim = 19.2\nt0+465s to t0+1356s : Rlim = 19.3\n\nMagnitudes were estimated with the nearby USNO-B1 stars\nand are not corrected for galactic dust extinction.",
  "circularId": 21027,
  "createdOn": 1492736267000,
  "email": "Alain.Klotz@free.fr",
  "subject": "Swift Trigger 748858: TAROT La Silla observatory optical observations",
  "submitter": "Alain Klotz at IRAP-CNRS-OMP  <Alain.Klotz@free.fr>"
}