Two main products make up OPTID : A) the database of matches and identifications to the FSS , and B) a finding chart service. Both of these are available through XCATSCAN .
The GSC/TIC
and COSCAT
were both searched to a radius of 
around each FSS
source. The GSC/TIC
provided an average of 
10
candidate matches to each of 762,499 FSS
sources over the whole
sky, while COSCAT
provided an average of 
300 candidate matches
to each of 299,972 FSS
sources in the south, with 
.
To make storage and complex searches more
tractable, these candidates were winnowed such that both the
GSC/TIC
and COSCAT
provide about 3--8 candidate matches per FSS source.
Separate databases were created for the GSC/TIC
and COSCAT
to
contain each catalog's optical data and the results of the OPTID
analysis.
Each candidate match carries the position, magnitude
and other information from its catalog and is tagged with two
estimates of the probability, 
, that it is the identification of
the FSS source, as well as other useful auxiliary information provided
by the identification process. One of the identification
probabilities takes into account the star/galaxy optical classification of
each candidate match, while the other makes no a priori
assumption about the star/galaxy nature of the candidate optical matches.
In addition,
the databases contain an estimate of the overall probability that
an identification exists in each catalog for each FSS
source.
As an observing aid, and a general analysis tool, OPTID
users can
request finding charts for a list of FSS sources, given by name.
These charts are a compact way of graphically
presenting a large amount of information about the given FSS
sources,
their spatial relationship to matches to
the GSC/TIC
and/or COSCAT
and the results of the OPTID
process.
Each chart
includes compactly presented information about the FSS
source --
including name, position, error ellipse, SNR, and IR color class --
and information about optical matches within
a box 
centered on the infrared source
-- including position, rough magnitude (represented
by symbol size), optical classification (star or galaxy) and, for
COSCAT
matches, image size and shape. Also, a few of the matches
most likely to be the identification of the FSS
source are tagged
with their relative rankings (best match, 2nd best, etc.) as well
as their 
estimates. This last feature is unique to OPTID
finding
charts and is particularly valuable.
In addition to the usual use of a finding chart at the
observatory, OPTID
finding charts are also helpful anytime a
detailed understanding of each FSS
source and its matches is
desired. The user can quickly spot potential trouble which may
render an identification invalid or call for more in-depth study.
The
third figure
is a sample chart showing the optical field at the position
of a faint (
Jy) galaxy-colored FSR
source,
Z12068-1823. It is identified with a B=19.1 galaxy with an
identification probability of 94%.