Here are some examples of using tmatch1
:
stilts tmatch1 matcher=sky values="RA2000 DE2000" params=20 \ action=keep0 in=crowded.vot out=sparse.vot
stilts tmatch1 matcher=skyerr values="RA2000 DE2000 RADIUS*4" params=40 \ action=keep0 in=crowded.vot out=sparse.vot
skyerr
matcher which determines the proximity threshold
on a row-by-row basis from values in the table - in this case 4 times
the value of the RADIUS column (this value must be in arc seconds).
The params=40
value does not affect the result, but it
gives the algorithm an idea of the rough scale of object separation.
stilts tmatch1 matcher=3d values="XPIX YPIX ZPIX" params=10 action=identify \ in=state.fit ocmd='select GroupSize>3' out=groups3+.fit
action=identify
parameter means that the input table
is written out with the same rows, but with additional columns indicating
which rows are associated with each other. One of these columns,
"GroupSize" gives the number of objects in each group.
The postprocessing filter ocmd='select GroupSize>3'
selects only those rows which are part of groups of three objects or
larger; singletons and pairs are discarded before writing the output file.
stilts tmatch1 matcher=sky values="ra dec" params=3 action=wide2 \ ocmd='keepcols "id_1 ra_1 dec_1 id_2 ra_2 dec_2"' in=galaxy.fits out=binaries.txt ofmt=ascii
ocmd
post-processing filter discards all of the
columns except the identifiers and sky positions for each object.
The output is to a text file.