{
  "bibcode": "2002GCN..1492....1W",
  "body": "G.G.Williams (Steward Observatory), C.Blake (CalTech/Princeton),\nDieter Hartmann (Clemson), and the S-LOTIS\ncollaboration report:\n\nThe error box of GRB020813 (HETE Trigger 2262, GCN 1471) was observed\nin R band with the 0.6m Super-LOTIS telescope, located at Kitt Peak,\nbeginning at 4.42 UT on August 13, 2002.  In total, 110 individual 60s\nimages were taken.  By coadding the first 9 images, taken between 4.42\nand 4.62 UT, the OT reported by Fox et al. (GCN 1470) was detected at\nthe 3 sigma level.  This represents the earliest detection of the OT\nthrough a standard photometric filter.  Using F band photographic\nmagnitudes from the GSC2.2, the magnitude of the OT was determined by\ncomparison to several nearby stars.  We report an R band magnitude of\n18.38+/-0.38 at UT 4.51.  This magnitude is consistent with a decay\nslope of approximately -1 to the later-time R band data reported by\nMasi (GCN 1484), Urata et al. (GCN 1485), and Kiziloglu et al. (GCN\n1488).  Analysis of the rest of the S-LOTIS data is in progress.\n\n========================================= \nOT 19:46:41.874 -19:36:04.81 (J2000)     \n=========================================\nR=18.38+/-.38 at UT 4.51 August 13, 2002.\n=========================================\n\n\nThis message may be cited.",
  "circularId": 1492,
  "createdOn": 1029384767000,
  "email": "cblake@phoenix.Princeton.EDU",
  "subject": "GRB020813: Early Time Magnitude",
  "submitter": "Cullen Blake at Princeton U.  <cblake@phoenix.Princeton.EDU>",
  "eventId": "GRB 020813"
}