{
  "bibcode": "1998GCN...165....1S",
  "body": "Bradley E. Schaefer (Yale) reports:\n\n\"I have obtained 19 images in the V and R bands of the joint RXTE/IPN\nregion for GRB981220.  The total integration time is 2.5 hours in the\nV-band and 2.25 hours in the R-band, with the filters alternating in time,\nfor a total time span of just over 5 hours. These images were obtained\nfrom 23 December 1998 00:52 to 05:55 UT with the Yale 1m telescope on\nCerro Tololo.\n\nNo variable source was identified in or near the GRB981220 region.\nComparisons were made with the Digital Sky Survey, for which no 'new'\nstars appear.  Also, comparisons were made between the first and last\nimages, separated by roughly 5 hours of time.  For the latter comparison,\nthe limiting magnitude for detecting change is close to V=22.0 mag.  As\nalways, further analysis can push somewhat deeper, yet it is clear that\nany associated optical transient must be close to this quoted limit if not\nfainter.\"",
  "circularId": 165,
  "createdOn": 914445073000,
  "email": "schaefer@grb2.physics.yale.edu",
  "subject": "GRB981220 Optical Observations",
  "submitter": "Brad Schaefer at Yale  <schaefer@grb2.physics.yale.edu>",
  "eventId": "GRB 981220"
}