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GCN Circular 210

GRB990123 optical observations
1999-01-24T15:35:49Z (25 years ago)
Paul Vreeswijk at U of Amsterdam <>
Eran Ofek and Elia M. Leibowitz, Wise Observatory, Tel Aviv University

>From 4 CCD frames of the object taken at the WO between Jan
24.0617-24.1162 we have determined an average R magnitude of
19.87+-0.2, with calibration based on 4 USNO A2.0 stars.  The decay
parameter in the R band over that time interval is -1.9+-0.1.  On Jan
24.0625, the color index of the object was B-R=-0.48+-0.25.

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