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GCN Circular 302

GRB 990506 optical observations
1999-05-08T21:14:49Z (25 years ago)
Krzysztof Z. Stanek at CfA <>
P. M. Garnavich, K. Z. Stanek and M. R. Garcia (Harvard-Smithsonian
CfA) report on behalf of the CfA GRB optical follow-up team:

We measured the object at RA 11:54:57.77, Decl -26:43:02.9 (J2000)
(coordinates based on the GSC catalog), reported by Vrba et al. to be
variable (GCN #300), in our R-band images taken with the 1.2-meter
telescope at the F. L. Whipple Obs. by N. Caldwell (May 7) and
K. J. Rines (May 8).  We find R=22.6 +/- 0.3 on average of two 15-min
images (May 7 03:15 UT) and R=22.5 =/- 0.3 on average of two 15-min
images (May 8 UT 04:48). The data were calibrated using Landolt
standard star RU149. This is consistent with the Vrba et al. object
being non-variable.

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