The VLT Survey Telescope ATLAS
  The VLT Survey Telescope (VST) ATLAS is an optical ugriz survey aiming to
cover ~4700deg^2 of the Southern sky to similar depths as the Sloan Digital Sky
Survey (SDSS). From reduced images and object catalogues provided by the
Cambridge Astronomical Surveys Unit we first find that the median seeing ranges
from 0.8 arcsec FWHM in i to 1.0 arcsec in u, significantly better than the
1.2-1.5 arcsec seeing for SDSS. The 5 sigma magnitude limit for stellar sources
is r_AB=22.7 and in all bands these limits are at least as faint as SDSS. SDSS
and ATLAS are more equivalent for galaxy photometry except in the z band where
ATLAS has significantly higher throughput. We have improved the original ESO
magnitude zeropoints by comparing m<16 star magnitudes with APASS in gri, also
extrapolating into u and z, resulting in zeropoints accurate to ~+-0.02 mag. We
finally compare star and galaxy number counts in a 250deg^2 area with SDSS and
other count data and find good agreement. ATLAS data products can be retrieved
from the ESO Science Archive, while support for survey science analyses is
provided by the OmegaCAM Science Archive (OSA), operated by the Wide-Field
Astronomy Unit in Edinburgh.
