`sextractor`¶

Synopsis¶

Means “Source Extractor”
Makes a catalog with positions (“astrometry”) and fluxes (“photometry”) out of your FITS image. Can also be used to fit/subtract the sky.

You need to have the 4 configuration (default.sex/param/nnw/conv) files in the same directory as your FITS image.
Edit them if needed. default.sex and default.param are the only ones you will have to care about. The first one contains general settings, the second one lets you chose the parameters you want to measure.

sex myimage.fits -c default.sex

…will write the catalog file, as configured in default.sex

Official manual

Inofficial (much funnier)