Index: trunk/psphot/doc/notes.20091026.txt
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+
+2009.10.26
+
+  I'm looking into psphot as applied to diff images.  For now, I am
+  running a comparison of a simtest output warp with the convolved
+  version of the same image as generated by ppSub.  
+
+  * we are losing the cores of bright stars, probably to the choices
+    in the FITS output 16-bit conversion (pixel-value -> NAN)
+
+  * errors for the convolved image seem to be smaller for the same
+    instrumental mags than for the warp (check chip).
+
+  * the psf model seems to be quite poor -- a lot of structure in the
+    psf core.
+
+  * (note: not a very good match with the warp image, though better)
+
+  * psfsub images seem to be slightly displaced in X-dir.  perhaps
+    because the convolution kernel has a bit of X-dir tilt in the
+    peak.  Try with PPSUB ISIS orders set to 0.0 
+
+2009.10.27
+
+  I need some psphot options / variants:
+
+  * forced photometry:
+
+    I should be able to do:
+    
+    psphotForced -file input.fits -psf psf.fits -src src.list output 
+    
+    and have it only perform the forced photometry on the sources listed
+    in src.list.
+
+  * psf model creation
+
+    I should be able to do:
+
+    psphotMakePSF -file input.fits -src src.list output
+
+    and have it generate a PSF model using the sources listed in
+    src.list
+