H. Pedersen, B. L. Jensen, J. Hjorth (Copenhagen), M. Holman (CfA, USA),
K. Aksnes, T. Grav, N. Haug, A. O. Jaunsen (Oslo), M. I. Andersen,
and H. Korhonen (NOT), report:
We have observed the position of GRB 990506, using the ALFOSC
instrument on the 2.56-m Nordic Optical Telescope, La Palma, Spain.
We covered almost the entire IPN+RXTE error box (Hurley et al., GCN 298),
using two separate pointings, each of which is 6' x 6'.
At each position, we obtained a 480 s R-band exposure, between
1999 May 6.91 - 7.05 UT (seeing 0.9" - 1.2" FWHM) and a 240 s R-band
exposure, on 1999 May 7.91 UT (seeing 0.7" FWHM).
We have compared the exposures internally, finding no evidence for
variable objects to a limiting magnitude of R = 22.0, for variability
amplitude above 0.3 magnitude.