                  The Aperture Photometry Package
                 ----------------------------------

The apphot package contains routines which perform aperture
photometry in circular and polygonal apertures using fractional pixel
techniques. No point spread function fitting techniques are employed.
The photometry routines are most suitable for use on uncrowded
or moderately crowded fields.

The apphot directory structure is listed below. The package organization
is by task, for example the center subdirectory contains routines
specific to the center task or by function, for example the nlfit
directory contains the non-linear least squares fitting routines.
The wphot task shares alot of code with the phot task. Similarly
the polymark task shares some code with the polyphot task.
The .h files are all in lib as many of them are shared by several tasks.

             |-aplib---------apphot routines used by several tasks
             |-aputil--------miscellaneous useful routines
             |-center--------routines specific to centering, the center task
             |-daofind-------routines specific to the daofind task
             |-doc-----------apphot documentation
|-apphot-----|-fitpsf--------routines specific to the fitpsf task
             |-fitsky--------routines specific to sky fitting, the fitsky task
	     |-lib-----------apphot definitions or .h files
             |-phot----------routines specific to the qphot/phot tasks
             |-polyphot------routines specific to the polyphot/polymark tasks
             |-radprof-------routines specific to the radprof task
	     |-wphot---------routines specific to the wphot task
             |-test----------directory of test data


Lindsey Davis
NOAO IRAF GROUP
November 1991
