sky
: Sky Matching
matcher=sky values*='<ra/degrees> <dec/degrees>' params='<max-error/arcsec>'
The sky
matcher compares positions on the celestial sphere
with a fixed error radius.
Rows are considered to match when the two (ra
, dec
)
positions are within max-error
arcseconds of each other
along a great circle.
In fact this matching is not restricted to equatorial coordinates -
the ra
and dec
parameters may represent
any longitude-like and latitude-like coordinates in degrees,
since the spherical geometry for the matching is unchanged under
such transformations.