Data products - IRAC
----------------------------

There are four fits files for each channel - data, coverage,
uncertainty and standard deviation fits images. The uncertainty image
attempts to estimate the error per pixel that arises due to all steps
in the mopex pipeline. It is probably a conservative error estimate,
but we suggest it be should be used for analysis, at least for this
data release.

For each channel, there is also a namelist file (ending in 'nl') that
was used to generate the mosaics in Mopex. Note that the bad pixel
value for the DCE mask section differs from the standard value, as
processing used the post-BCD SpUDS pipeline to apply additional
corrections. 

Finally, the FIF.tbl file defines the common reference frame onto
which all the channels were projected. 

Processing started with the BCD frames supplied from the Spitzer
Science Center IRAC pipeline, version S17. These frames were processed
through the SpUDS custom post processing pipeline, which performs
tasks such as background matching, muxbleed and latent correction, and
the like. This pipeline is conceptually similar to the COSMOS and 
IRAC GTO pipelines. It also closely resembles the S17 'post
processing' pipeline, which produces the CBCD files, but with slightly
better removal of large scale gradients, and better background
matching btween individual AORs.

As this is the first release of data from SpUDS, it is likely that the
data reduction is not yet optimal, and that problems remain. It is
likely that the quality of channels 1 and 2 will not improve
significantly in the future, but we hope to get better sky background
and gradient removal in channels 3 and 4 in future releases.