B.36.2 Examples

Here are some examples of using tskymap:

stilts tskymap in=iras_psc.fits lon=RA lat=DEC out=iras_map.csv

Writes a table representing a density map of IRAS point sources on the sky. The output is a 2-column CSV file: the first column is pixel index, and the second column is the number of rows in the input table whose (RA,DEC) positions fall within that pixel. The default tiling is used (currently level 5 HEALPix, which has 12288 pixels).

stilts tskymap in=2mpz.fits icmd='addskycoords fk5 galactic ra dec glon glat'
               lon=glon lat=glat tiling=hpx6
               cols='jCorr-hCorr hCorr-kCorr jCorr-kCorr' combine=median
               count=false
               complete=true
               out=2mpzColors.fits

Writes a table with columns giving median J-H, H-K and J-K colours, but no source count column, from the sources in the file 2mpz.fits, aggregated over each tile of a level 6 HEALPix grid. The input table has equatorial coordinates, but the addskycoords filter has been used so that the grid is laid on the sky with galactic coordinates. Setting complete=true guarantees that a row is written to the output file for every sky pixel, including empty ones.

stilts tskymap in=gums_lmc.fits lon=alpha lat=delta
               tiling=hpx14 complete=false omode=count

This prepares a source count map at healpix level 14 (3 billion pixels) from the given input table. Since complete=false, only rows for non-empty pixels are included in the output table. Then, since the output mode is count, these rows are just counted, discarding the pixels themselves, giving the number of level-14 healpix pixels touched by the sources in this input file. Note this is not necessarily the most efficient way to caluclate coverage information.