GROUP: DAOPHOT GROUP Command

Form: GROUP [CRIT=crit]
GROUP
Groups stars according to user specified PSF overlap
OLDGROUP
Groups stars in the old DAOPHOT way, just by distances to neighbors
GROUP splits stars into separate groups for possible use during the PSF-fitting procedure. OLDGROUP (or GROUP with option IGROUP=1) splits stars just on the basis of the distance to the nearest neighbor, and needs a critical separation as input. GROUP (with option IGROUP=0) uses brightness information and information about the PSF as well, and uses a critical brightness ratio as input.

GROUP uses as input an output file from the PHOTOMETRY command. The program will prompt for a critical separation or critical ratio, or it can be specified with the CRIT= keyword. The command will also prompt for an input aperture photometry file, an output group file, and a PSF file (for GROUP IG=0). Alternatively, these files can be specified with the DAOFILES MAG=magfile GRP=grpfile PSF=psffile command.