skyerr
:
Sky Matching with Per-Object Errors
matcher=skyerr values*='<ra/degrees> <dec/degrees> <error/arcsec>' params='<max-error/arcsec>'
The skyerr
matcher compares positions on the celestial
sphere using error radii which can be different for each row.
Rows are considered to match when the separation between the
two ra
, dec
positions is smaller than
both the fixed max-error
value
and the sum of the two per-row error
values.
If either of the error
values is blank,
then any separation up to max-error
is considered a match.
According to these rules, you might decide to set max-error
to an arbitarily large number so that only the sum of error
s
will determine the actual match criteria.
However please don't do this, since max-error
also functions as a tuning parameter for the matching algorithm,
and ought to be reasonably close to the actual maximum acceptable
separation.
As with sky
matching,
other longitude/latitude coordinate pairs may be used in place of
right ascension and declination.