{
  "bibcode": "2006GCN..5073....1T",
  "body": "I.Takahashi, T.Uehara, K.Yoshida, A.Kobayashi,\nT.Koshiishi, K.Tanaka, Y.E.Nakagawa, S.Sugita, K.Yamaoka,\nA.Yoshida (AGU) report:\n\nAfter the previous report (GCN 5065), we carried out\nfurther photometric calibrations for the observations\nof the GRB 060502B field (Troja et al. GCN 5055, GCN 5059).\nWe have taken 100 frames of R band image with 20s exposure\neach and photometric calibration was mede by every 20 frames\nby comparing with USNO A2.0 stars in the same field.\nThe 3 sigma limiting magnitude of each combined image\nis as below.\n\ndata set  mean time     time - burst[s]  lim-mag R (3sigma)\n======================================================\n1st       17:30:00 UT   319              16.12 +/-0.16\n2nd       17:37:35 UT   774              16.26 +/-0.19\n3rd       17:45:13 UT   1232             16.00 +/-0.05\n4th       17:52:44 UT   1683             16.00 +/-0.02\n5th       18:00:13 UT   2132             16.30 +/-0.02",
  "circularId": 5073,
  "createdOn": 1146770110000,
  "email": "yamaoka@phys.aoyama.ac.jp",
  "subject": "GRB 060502B: AROMA refined photometric calibration",
  "submitter": "Kazutaka Yamaoka at Aoyama Gakuin U  <yamaoka@phys.aoyama.ac.jp>",
  "eventId": "GRB 060502B"
}