build-astrometry-index - Create astrometry.net index files
build-astrometry-index [options] -i catalog -o file -P scale
build-astrometry-index takes a FITS catalog table containing at least RA, DEC, and magnitude columns and converts it into an index file that can be used by the astrometry.net programs like solve-index (1).
-i catalog Input FITS catalog: source RA,DEC, etc. -e extension FITS extension to read when -i is specified. -1 index Share another index's stars (alternatively to -i/-e). -o file Output filename for index -N nside Healpix Nside for quad-building -l size Minimum quad size (arcminutes) -u size Maximum quad size (arcminutes) -P number Use 'preset' values for -N, -l, and -u. The scale-number is the last two digits of the pre-cooked index filename -- eg., index-205 is -P 5. -P 0 should be good for images about 6 arcmin in size and it goes in steps of sqrt(2), so: -P 2 should work for images about 12 arcmin across -P 4 should work for images about 24 arcmin across -P 6 should work for images about 1 degree across -P 8 should work for images about 2 degree across -P 10 should work for images about 4 degree across etc... up to -P 19 -S column Sort column (default: assume the input file is already sorted) -f Sort in descending order (eg, for FLUX); default ascending (eg, for MAG) -A column Specify the RA column name in the input FITS table (default "RA") -D column Specify the Dec column name in the input FITS table (default "Dec") -B val Cut any object whose sort-column value is less than val; for mags this is a bright limit -U Healpix Nside for uniformization (default: same as -n) -H big healpix Big healpix; default is all-sky -s Nside Big healpix Nside; default is 1 -m margin Add a margin of margin healpixels; default 0 -n sweeps Sweeps (ie, number of stars per fine healpix grid cell); default 10 -r radius Deduplication radius in arcseconds; default no deduplication -j jitter Positional error of stars in the reference catalog (in arcsec; default 1) -d dimquads Number of stars in a "quad" (default 4). -p passes Number of rounds of quad-building (ie, number of quads per healpix cell, default 16) -R reuse Number of times a star can be used (default: 8) -L max-reuses Make extra passes through the healpixes, increasing the -r reuse limit each time, up to max-reuses. -E Scan through the catalog, checking which healpixes are occupied. -I id Set the unique ID of this index -M In-memory (don't use temp files) -T Don't delete temp files -t dir Use this temp directory (default: /tmp) -v Add verbosity.
The Astrometry.net team. Principal investigators are David W. Hogg (NYU) and Dustin Lang (CMU).
hpsplit (1), solve-field (1) For a tutorial, see http://astrometry.net/doc/build-index.html
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