GCN Circular 91
Subject
GRB980519 optical observations
Event
Date
1998-05-22T23:19:18Z (28 years ago)
From
Alan Diercks at U.Washington <diercks@astro.washington.edu>
On behalf of the Manastash Ridge Observatory GRB team, A. Diercks &
J. Morgan observed with the MRO 0.76m telescope the optical transient
(OT) discovered by Jaunsen et al. (GCN #78) in the BeppoSAX error box
of GRB 980519. Conditions were cloudy with roughly 3 arcsec seeing.
Photometry by E. Deutsch & A. Diercks on a 12,000s series of images
centered around May 20.4 UT yields the following magnitudes and
uncertainties for the OT and reference objects:
ID R mag RelErr
-- ----- -----
OT 21.07 0.25
A 17.93 0.05
B 19.36 0.08
C 18.06 0.05
Absolute calibration is based only on R magnitudes of reference stars
reported by Bloom et al. (GCN #87). No independent calibration was
possible due to thick clouds. Our measurement is consistent with the
nearly simultaneous R magnitudes reported in GCN #80 and GCN #82.
This note can be cited.