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GCN Circular 370

GRB 990704, optical observations
1999-07-05T22:57:23Z (25 years ago)
Alan Diercks at U.Washington <>
Alan Diercks, Kevin Krisciunas, and Eric Deutsch (Univ. Washington)
report on behalf of the UW and LONEOS GRB collaborations:

The position of the possible optical counterpart to GRB 990704
reported by Maury et al. (GCN 363) (12:19:29.29 -03:47:25.8) was
imaged in the course of the LONEOS project approximately one month
ago, June 6, 1999.  Three 60s, un-filtered CCD exposures were taken
with the 60cm Schmidt telescope.  Combining these images, we detect
the object noted by Maury et al with an un-filtered magnitude of m =
19.6 +/- 0.3 relative to the "red" magnitude of USNO-A1.0 star
U0825_07735496.  We measure the following unfiltered magnitudes for
three stars from the USNO-A1.0 Catalog:

USNO number     RA(2000)    DEC(2000)   USNO     UW/LONEOS
					r_mag	  mag
U0825_07735496 12:19:33.74 -03:47:25.3  15.6     15.6 +/- 0.1 *calibrator*
U0825_07735738 12:19:36.43 -03:47:12.6  16.5     16.8 +/- 0.1
U0825_07735688 12:19:35.95 -03:46:32.9  16.5     16.7 +/- 0.1

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