sky3d: Spherical Polar Matching
matcher=sky3d values*='<ra/degrees> <dec/degrees> <distance>' params='<error/units of distance>' tuning='<bin-factor>'
ra/degrees: Right Ascension
distance: Distance from origin
error/units of distance: Maximum Cartesian separation for match
bin-factor: Scaling factor to adjust bin size; larger values mean larger bins
sky3d matcher compares positions in the volume of
the sky taking account of distance from the observer.
The position in three-dimensional space is calculated for each
row using the
as spherical polar coordinates, where
distance is the
distance from the observer along the line of sight.
Rows are considered to match when their positions in this space are
error units of each other.
The units of
error are the same as those of
other longitude/latitude coordinate pairs may be used in place of
right ascension and declination.