The source measurements are written to a catalogue (which can be of several different formats), so that they can be analysed (possibly by a catalogue handling package like CURSA - SUN/190).
EXTRACTOR, is based on the SExtractor program which is described in the SExtractor's User Guide (MUD/165). Consult this about all the various options that are available and for the rationale behind the program.
Using this parameter you may give two image files. The first image will be used for detection and parameterising and the second will be used to actually measure the data values. Using this method allows you to measure the same objects many images, or to use a high signal to noise image to determine the measurement regions on a low signal to noise image
The measurements made are determined by a list of parameters
in the file
$EXTRACTOR_DIR/config/default.param. Again if you want measurements that are not available by default, you must take a copy of this file and edit it. Remember to also change default.sex to use this file (otherwise you will continue to use the system-wide defaults).
One off modifications of parameters can be made using the KEYWORDS, NAME and VALUE parameters.
EXTRACTOR An Astronomical Source Detection Program