This is a single script that runs all of the steps needed to perorm aperture photometry using apphot. It really beagn as a testbed code for developing my routine(s) for deriving ZP and sky surface brightness estimates using my imgcat0 source catalogs. This routine queries the user for information like the size of the aperture to use or the minimum numer of pixels to allow when gathering sources that are to be photometered.

 
% apphot_interactive --help   
% apphot_interactive ./local_red/FIXUP/20191022T025524.2_acm_sci.fits  

 
20191022T025524.2_acm_sci_apertures.cdfp
20191022T025524.2_acm_sci.boxlims
20191022T025524.2_acm_sci.cdfp
20191022T025524.2_acm_sci.cdfp.reg
20191022T025524.2_acm_sci.fits
The image with the best WSC calibration and the files collect with image_catalogs. 
These files are gathered and sifted (i.e the larger objects extracted) to make the 
files specifying where apertures are to be measured. 

APS.cdfp, APS.parlab, APS.reg, APS.table
 The aperture photometry from apphot in a cdfp (with updated Ra,Dec) and table file.
The value in these: 
% cat APS.parlab
Xpix  X pixels (aperture X center)                   
Ypix  Y pixels (aperture Y center)                   
Xcen  X center, pixels (intensity weighted centroid) 
Ycen  Y center, pixels (intensity weighted centroid) 
Mag30  magnitude (assuming zp=30)                     
MeanAp  Average value per pixel in aperture           
MeanSky Average value per pixel in sky annulus       
Npix    Number of pixels in aperture                   
Fpeak   Peak pixel value (no bkg-sub, image ADU)       
Mtype   marker code (1=circle,2=box,3=ellipse)         

P.cdfp, P.cdfp.reg
  The PS1 (PANSTARRS) cdfp and regions file (the cdfp was originally gathered with DSSBASE routines) 
% head -4 P.cdfp
RA_hrs,DEC_deg,g,r,i,B,V,R,                                                     
  19.738534927  26.168968201    21.114    19.791    19.017    22.050    20.306    19.521
  19.738191605  26.164478302    21.462    19.904    19.106    22.530    20.513    19.630
  19.738920212  26.166263580    20.256    18.707    17.635    21.319    19.313    18.387

photom2_pars.in
  Just one thing now:  the fullpath address of the background image established by image_catalogs.