NAME:
    itool_ppsav
 PURPOSE: (one line)
    Save itool photometry parameters to a file.
 DESCRIPTION:

 CATEGORY:
    Widgets
 CALLING SEQUENCE:
    itool_ppsav, ph_parms
 INPUTS:
    ph_parms : The photometry parameters structure (See itool.pro).
 OPTIONAL INPUT PARAMETERS:

 KEYWORD PARAMETERS:
    ERROR_STR = A string variable in which an error message may be returned.
                A null string is returned, if no errors were encountered.
 OUTPUTS:

 COMMON BLOCKS:

 SIDE EFFECTS:

 RESTRICTIONS:

 PROCEDURE:

 MODIFICATION HISTORY:
    2004, Apr, DWL. adapted from it_ppsav.pro. Added some GUI message
 dialogs.
    2006/5/22 Peter L. Collins, Lowell Observatory
                added the CCD readout noise parameter (rdnoise).