{
  "bibcode": "1999GCN...204....1Z",
  "body": "GRB 990123 Optical Observation\n\nJ. Zhu, H. T. Zhang, on behave of the Beijing Astronomical Observatory GRB \nteam, report:\n\n\"R-band image of the BeppoSAX WFC error circle of GRB 990123 (Piro, GCN #199)\nwere obtained on 1999 Jan 23.756 UT, 8.5 hours after the GRB, with the BAO \n0.6/0.9m Schmidt telescope in Xinglong. The weather was bad, so only one\n20-min. exposure image taken under thin cloud was usable (FWHM=6\").\n\nCentral part of the image is posted at\nhttp://vega.bac.pku.edu.cn/~zj/grb/grb990123.gif.\n\nA faint object could be seen closed to the optical candidate position \nsuggested by S. C. Odewahn et al. (GCN, #201). Its position from our \nmeasurement is RA=15:25:30.28, Dec=+44:45:59.0 (1 sigma = 0.5\"), with \nmagnitude of 19.2 (+/- 0.5 ?) if using the following 4 stars' magnitude \ninformation from the USNO-A V1.0 catalogue (David Monet, et. al.):\n\n=========================================================\nNo. RA_mea (2000.0) Dec_mea  RA_cat (2000.0) Dec_cat mag.\n--- -----------------------  ----------------------- ----\n1   15:25:27.03 +44:46:23.3  15:25:27.04 +44:46:23.2 14.4\n2   15:25:36.47 +44:44:37.6  15:25:36.45 +44:44:37.6 15.3\n3   15:25:32.57 +44:44:29.9  15:25:32.66 +44:44:29.9 18.5\n4   15:25:27.42 +44:44:42.5  15:25:27.48 +44:44:43.6 19.7\n=========================================================\n\nThe object in our image seems slightly extended and slightly southwest\ncomparing with the discovery image of Odewahn et al., but it seems\nto be impossible to confirm from only one image in not good quality.\nHowever, it could be concluded that if such an object (in our image)\nwould not be real, the optical transient in Odewahn et al.'s images must \nbe faded largely between the 4.6 hours interval.\n\nThis report may be cited.\"",
  "circularId": 204,
  "createdOn": 917131471000,
  "email": "grb@bac.pku.edu.cn",
  "subject": "GRB990123 Optical Observation",
  "submitter": "Jin Zhu at Beijing Obs  <grb@bac.pku.edu.cn>",
  "eventId": "GRB 990123"
}