TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  3200
SUBJECT: GRB 050408: Mercator Optical Observations
DATE:    05/04/09 05:17:53 GMT
FROM:    Peter Curran at U of Amsterdam  <pcurran@science.uva.nl>

K. Wiersema, P. Curran (University of Amsterdam),
K. Lefever, H. van Winckel, C. Waelkens (Katholieke Universiteit Leuven),
O. van Braam, Y. Grange, R. de Rooij, A. de Vries, L. Waters, (University
of Amsterdam),

report:

"We have taken R- and I-band images of the optical afterglow
reported by de Ugarte Postigo et al. (GCN 3193) of the
HETE-2 GRB 050408 (Sakamoto et al., GCN 3189) at the
1.2m Mercator Telescope at La Palma.

The R-band observation started at 20:56 UT and consisted of
3 x 5m, 1 x 3m and 1 x 8m exposure time, making the
total exposure time 26 minutes, with midpoint 4.82h after burst.
The I-band observation started at 21:30 UT and consisted of
2 x 5 minutes exposure time, with midpoint 5.22h after burst.
We calibrate our photometry using the USNO-B catalogue values.
We find an R-band magnitude of 21.25 +/- 0.2 and a
I-band magnitude of 20.4 +/- 0.3.

We thank the staff of the Mercator Telescope for the
excellent assistance."