GCN Circular 91

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.

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