GCN Circular 3246

M. Nysewander, D. Reichart, D. Lamb, and D. York report:

Using ugriz magnitudes from the SDSS DR3 and the transformation
equations of Smith (2002; AJ, 123, 2121), we have calculated the
UBVRcIc magnitudes of 50 sources in the field of GRB 050408:

http://www.physics.unc.edu/~mnysewan/grb050408_fc.txt

Systematic errors are typically  0.02 mag in the gri bands and  0.05
mag in the u and z bands.  Statistical errors begin to dominate in u
and z at roughly 21 mag and in gri at roughly 21.5-22 mag.  All of
these sources have been classified as stars by the SDSS frames
pipeline; however, some of the fainter sources may be galaxies,
regardless of this.

Users can find the statistical and systematic error on the magnitude of
any SDSS object in the field at

http://cas.sdss.org/astro/en/tools/explore/obj.asp?ra=180.571087&dec=10.850506

by clicking on the "Field" button under "PhotoObj" in the column at the
far left, and make their own decision about whether an object is a
galaxy or a star at

http://cas.sdss.org/astro/en/tools/chart/navi.asp?ra=180.571087&dec=10.850506